LV10820B - Polygonal information encouding article,process and system - Google Patents

Description

LV 10820

POLYCONAL INFORMATION ENCODINO ARTICLE, PROCESS AND SYSTEM 1. Fleld of the Invention

This invention relates to an improved optically read-able label and a reading systera therefor, and, in particular, to an improved optically readable label, attaehed to or printed on a subatrate, for atoring Information vithin a tvo»dimensional data array, comprising a multiplicity of polygona «rranged in a predetermined geometric pattern, and aaid polygons havir.g at leaat two different opticcl propertiea. 2. Statement of Related Art

Merchandiae, varioua component parta, lettera, pack-agea, eontainera and a vhole gamut of related items being ahipped or transported, frequently are reguired to be identlfied with Information aa to origin, flight number, destinaticn, name, price, part number and numeroua other Rinda of Information. In other applicationa, reading encoded information printed on labels af-fixed to auch items permita automation of saies figurēs and m-ventory or the operation of electronic caah registers. Other applicationa for auch encoded labela include the automated rout-ing and aorting of mail, parcela, baggage, and the like, and the placing of labels bearing.manufacturing inatructions on raw matē· riala or component parta in a manufacturing process. Labels for theae types of articlea are conventlonally marked vith bar codea, one of which is the Universal Product Code. Numerous other bar code aystems are alao knovn in the art.

Commercially-availabie bar code systema typieally laek aufficient data density to accommodate the present and increasing need to encoda mora and more information on labels of increas· ingly amaller aize. Attempta to reduce the overall sire and spacing of bara in varioua bar code systema to increase data 2- density have not eolved the problem; optical scanners having suf-ficient reaolution to detect bar codea comprlsing contrasting bars spaced five mils or less apart are generally not economic-ally feasible to manufacture because of the close tolerances in-5 herent in the label printing process and the sophisticated optical apparatus required to resolve bit-encoded bars of these dimensions. Alternatively, to accommodate increased amounts of data, very large bar code labais must be fabricated, with the result that such labels are not compact enough to fit on small 10 articles. Another important factor is the cost of the label medium, such as paper. A.small label has a smaller paper cost than a large label; this cost is an important factor in large volume operations.

Alternatives to bar codes include; circular formāts 15 employing radially disposed wedge-shaped coded elements, such as in U.S. Patent 3,553,438, or concentric black and white bit-encoded rings, such as in U.S. Patents, Nos. 3,971,917 and 3,916,160; grids of rows and columns of data-encoded squares or rectangles, such as in U.S. Patent No. 4,286,146; microscopic 20 spots disposed in celis forming a regularly spaced grid, as in U.S. Patent No. 4,634,850; and densely packed multicclored data fields of dots or elements, such as described in U.S. Patent No. 4,488,679. Some of the coding systems described in the foregoing' examples and other coding systems knovn in the art primarily suf-25 fer from deficiencies in data density, such as in the case of encoded circular patterns and grids of rectangular or square boxes. Alternatively, in the case of the grids comprised of microscopic spots or multicolored elements referred to above, such systems reguire special orientation and transport means, thus 30 limiting their utility to highly controlled reading environments.

Due to the size and speed of modern conveyor systems, (utillzing conveyor belt vldths of 3 to 4 feet, for example) and having belt speeds approaching 100 inches per second or more, carrying packages of varying heights on which Information encoded 35 labels are affixed, and the need to utilizē a small, inexpensive, -3- LV 10820 compact label of about one square inch, great strains ara placed on the optlcal and decoding systema required to locate and read the data encoded labels on these rapidly moving packages and the like. There are difficulties in the optlcal acanner aimply acquiring the label image. Furthermore, once acquired or Identi» fied, the Label image muat be accurately decoded before the next operation on the package in the conveyor system takes place, often in a fraction of a second. These problēma have led to the need for providing a simple, rapid and Low-cost means of signal» ing the preaence of a data-encoded label vithin the field of view of an optical acanner mounted in a manner to permit acanning the entire conveyor belt. Thia feature deairably ia coupled with a high denaity data array, deacribed in more detail below.

Data arraya containing acquiaition targets are known in the art; for example, concentric geometric figurēs, including rings, squares, triangles, hexagons and numerous variations thereof, such as described in U.S. Patents Nos. 3,513,320 and 3,603,728. U.S. Patents Nos. 3,693,154 and 3,801,775 also de-acribe the use of aymbols comprising concentric circies aa Identification and position indicatora, which aymbols are affixed to artlcles to be optically scanned. However, these ayatema employ two separate symbols to determine the identification of the data field and its position, thereby increasing the complexity of the logic circuitry reguired to detect the symbols, as well as reduc-ing the data-carrying capacity of the associated data field.

Also, vhen two symbols are used, damage to one causes problēma in locating the position of the data field and the attendant ability to recover Information from the data field. In the latter system, separate position and orientation markings are utllized at ^pposit-ends of data tracks having data-encoded linear markings of only limited data carrying capability.

The foregoing systems are generally scanned with an optical sensor capable of generatlng a video signal output corres-ponding to the change in intenaity of light reflected off the data array and position and orientation aymbols. The video out- 4- put of euch systema, after it ie digitized, haa a particular bit pattern which can be matched to a predetermined bit secjuence.

These systema, hovever, auffer the dravback of requiring tvo aeparate symbola for firat aacertaining the image and aecondly S determining ita orientation. Alao, the process of having to match the digitized aignal output of the optical aenaor with a prede-termined bit aequence representing both the poaition and orientation symbola, ia more likely to producē erroneoua readinga thai* the process and eystem of thia invention, because the prior art 10 label acquiaition aysteras provide an inflexible characterization of the acquisition target aignal Ievel. U.S. Patent No. 3,553,438 diacloses a circular data array having a centrally-located -acquiaition target comprising a aeries of concentrie circlea. The acquiaition target providea a 15 means of acquiring the circular label by the optical aenaor and determining ita geometric center and thereby the geometric center of the circular data array. Thia ia done through logic circuitry operating to recognize the pulsē pattern representative of the bulla-eye configuration of the acquiaition target. Hovever, as 20 for bar codea, the data array has only a limited data capacity and the syatem requirea a aecond circular scanning process. Use of both a linear and circular acan for a system of such limited data capacity creates undesirable complexity in the system for a alight gain in data capacity over conventional bar codea. 25 To increase the data carrying capacity of data arrays, codea employing multiple high density colored dots have been developed, aa deacribed in U.S. Patent No. 4,488,679. Syatema of the type deacribed in U.S. Patent No. 4,488,679, hovever, require the use of hand-held optical acannera, vhich a„e totally incapable 30 of recording and decoding rapidly moving data arrays on a package being transported on a high-speed conveyor belt. Analogoualy, high denaity coding eyatene employing microacopic data-encoded apota, aa deacribed in U.S. Patent No. 4,634,850, require special tranaport means, thereby enauring that the data array ia moved in 35 a apecific direction, rather than aimply at a random orientation, -5- LV 10820 as might be found with a package being transported on a conveyor belt or the llke. Thus, the coded label must be read track by track, utilizing a linear scanner coupled vith labai transport means to properly dacode the Information ancoded on the label.

Alao, in thia patent, the position of the card in relation to the sensor must be very carefully controlled to be readable.

Multiple colors have also been utilized in the art of produeing bar code systems so aa to overcome the optical problēma of scanning very minūte bars. A bar code utilizing more than two optical properties to encode data in a data array( by for instance, use of alternating black, gray and vhlte bars, is described in U.S. Patent No. 4,443,694. Hovever, systems of the type described, although an improvement over earlier bar code systems, neverthe-less fail to achieve the compactness and data density of the invention described herein.

OBJECTS OF THE INVENTION

In view of the foregoing dravbacks of prior optical coding systeme, it is a principal object of this invention to provide new and improved compact, high-information-density, optically-readable labels.

Another object of the invention is to provide new and improved optically readable labels vhich may be encoded vith abodt 100 highly error-protected alphanumeric characters per square inch of label area.

Stili another object of this Invention is to provide nev and improved compact high-information-density, optically-readable labels vhich may be read by an optical sensor vhen the label is affixed to a package or other llke aiticle being transported on a high speed conveyor system, vlthout regard to the orientation of the package thereon or the variability of the heights of said packages upon vhich the optically«readable label is affixed. A concomitant object of this invention is to provide an optically-readable label and decoding system combination, so that 6 the label is capable of being reliably decoded even if tilted, curled, varped, partially obliterated or partially torn.

An additional object of this invention la to provide methoda for determining the locatlon of a Label passing under an opticai sensor at hlgh speed and decoding sald label vith a high degree of data integrity.

It is a further object of this invention to provide improved methods of encoding compact, high-information-density, improved, optically-readable labele by dividing the Information to be encoded into higher and lower priority messages, to create a hierarchy of messages, which are separately error protected to ensure the integrity of the encoded Information.

It ia yet another object of this-invention to provide improved methods and syatems of encoding and decoding compact, high density, Improved, optically-readable labele vhich include error correction capabilities, so as to restore misread or miss-ing Information and to do so with a preferenee to the high prlor-ity encoded message, A further object of this invention is to producē in-expensive opticaily-readable labels by conventional prmting means and decoding same, with relatively inexpensive logic circuitry.

Further object» and advantages of the invention wili become apparent from the description of the invention vhich follovs.

SUMMA*Y OF THE INVENTION

The present invention comprlsea an optically-readable label for atoring data encoded in bit form, comprising a predeter-mined tvo-dimeneionai data array of a multiplicity of information-encoded polygons arranged contiguously, partially contiguously or noncontiguously in a predetermined two-dimensional pattern and having at least tvo different opticai properties as veli as methods and apparatus for encoding and decoding such optically-readable labels. 7- LV 10820

Optically readable labels of the invention may comprise predetermined tvo-dimenaional geometric arrays of polygons where the geometric centers of euch polygona lie at the vertices of the intersecting axes ae more fully discusaed belov of a predetermined 5 tvo-dimenaional array and where the polygons have one of at least tvo differerrt optical propertiea. The polygona of auch optically readable labela may be regular or irregular polygons and the tvo-dimenaional arrays of polygons on the optically readable labela may have tvo or more equally- or unequally-angularly spaced axea 10 in the planē of the label.

Optically readable labela may be printed vith config-urationa of polygona vhich are totally contiguous, partially contiguous or noncontiguous. The latter tvo configurations in-herentl.y define a multiplicity of interatitial apacea on the 1S optically readable label betveen adjacent polygona. Such interatitial apacea may have the aame or different optical prop-erties aa the tvo or more optical propertiea of the polygons. Tvo-dimenaional arraya of contigruoua polygona having five or more sides are usable as optically readable label configurationa of 20 the invention. Also, tvo-dimenaional arrays of either regular or irregular, and either partially contiguous or noncontiguous, polygons having three or more sides, vhen prearranged on predetermined axes of such arrays, may be encoded and decoded in* accordance vith the processes of the invention. 25 In addition to the foregoing vārieties of geometric polygonal celle, arrangements of such polygonal celis, and geom-etriea of the optically readable labela formed by such arrange-ments of polygonal čella, the optically readable labela of the invention may optionally contain an acquisltion target comprising 30 a seriea of concentric rings to aid in the locating of the optically readable labela on the articles upon vhich they are affixed, particularly in dynamic label reading ayetema.

In a preferred embodiment of the invention, the data ‘ array compriaea a generally equare-ahaped array of about one 35 aguare inch, having contiguously-arranged hexagona forming rove 8 and columns.and a centrally-located acqulsition target having a geometric center whlch defines the geometric center of the data array. The acquisition target may be any of a number of geometrlc shapes having optlcal propertles capable of generatlng an easily recognizable video signal vhen scanned vith an optlcal sensor across a linear scan lir.e passlng through the geometric center of the acquisition target. In a preferred embodiment, the acquisition target is a plurallty of concentric rings of contrast-ing reflectivities, which vill yield a periodic video signal vhen scanned linearly. By uslng analog filter means as part of the method of Locating and decoding the data array, the signal generated by the optical sensor is compared directly vlth a pre-determined freguency, thereby alloving rapid and precise matching of the freguencies and conseguent determination of the location of the data array affixed to a substrāts. The analog electrical signal output from the optical sensor representing the Information· encoded label is then digitlzed and decoded. Utilizing an analog bandpass filtering step permits label acguisition to occur vithout the need for decoding the information-encoded label. By locating the center of the acguisition target a reference point on the data array may be determined. If the center of the acquisition target is located at the center of the label, a simultaneous determination of the center of the acguisition target and the data array may be accompllshed. A central location of the acquisition target on the label is preferred, but not required, in the practice of the subject invention.

The optically-readable data array of the present invention is capable of encoding 100 or up to several hundred or more error protected alphanumerie characters in an area of about one square lnch vhen hexagons are encoded utilizing three reflective propertles, such as the colors black, vhite and gray. For a sensor vith a glven optical resolution, the system of the invention permits a much denser Information packing capability than is possible vith bar code systems. For exaaple, if a high resolution optical sensor is used vith the system of this invention, hundreds -9- LV 10820 of alphanumeric charactera may be encoded ln a square inch. Alternatīvai/, 100 charactera per aguare Inch may easlly be de-tacted with a ralatlvely low raaolution aensor vith the aystem of this invention.

Optlcally-readable labela of the present invention may be produced vith varying data densitiea by utllizing aa fev aa tvo or more contrasting optical properties. Creater data denai-tiea and the incluaion of an acquisition target in the system of this invention require a acanning apparatua of increasing com-plexity and the addition of more elaborate decoding algorithma to read the encoded measage, vhen čompared vith a bar code reading aystem.

In thia invention, data encoding may be accompliahed by encoding a plurality of bita from a binary bit atream into a cluater of contlguous hexagons, each hexagon having or.e of at leaat tvo optical properties, although the encoding could alter-natively be done on a hexagon-by-hexagon baais. The digital bit atream may be generated by a Computer, baaed upon data entered manually or othervise converted into a binary bit atream, or may be provided aa a prerecorded digital bit atream. The data to be encoded ia bit-mapped in a predetermined seguence ar.d vithin pre-determined geographical areas of the data array to increase the number of transitiona betveen hexagons having different optical properties.

In the preferred embodiment of the present invention, the messages to be encoded are divided into high and lov priority messages, vhich are separately mapped in different geographic areas of the data array. The high priority measage may option-ally be duplicated in the lov priority measage area to reduce the possibility of loaing the high priority message due to scanning errora cauaed by smudges, teara, folds and other types of damage to the data array. The high priority message ls encoded in a Central area of the data array, near the acquisition target con-tained in the preferred embodiment, in order to protect the mes-aage from damage vhich is more likely to occur to the peripheral 10- areas of the data array. Error correction capabilitlea are desir-ably lncorporated ln the data array, utilizing the large informa-tion-carrying capacity of the preaent lnvention, to ensure a very high degree of data integrity upon decoding the measage.

In practicing the lnvention, a pixel grld of sufficient density to print the label vith hexagons of differer.t optical propertles ls utilized, although alternatlve printir.g processes may be used vithout departing from the spirit of the lnvention.

The pixel grid le bit-mapped ao that, when the label ia printed, •the optical propertiea of each hexagon are predetermined, ao that they may later be decoded to recover the data desigr.ated by the encoding of the individual hexagona. Thia type of printing pro-ceaa ia well knovn in the art and Standard printera and bit map-ping techniguea may be used to print hexagons having the optical propertiea required by thia lnvention.

The preaent lnvention provides a nev and improved procesa for retrievlng the data encoded in the bit-mapped array of polygons, preferably hexagons, forming the data array. Encoded labais may be paased through a predetermined lllumir.ated area and optically acanned by means of an electronically operated optical aensor or a hand-held scanr.er may be paased over the labela. The optical sensor producēs an output vhich ia an analog electrical aignal corresponding to the intenaity of the individual reflective property of an area of a label, as recorded by the individual pixels of the optical sensor. By means of an analog filter, the analog signal of the optical sensor is first compared to a predetermined frequency value corresponding to that of a predetermined acguiaition target if it ia preaent on the data array. Once a good match la found, the label ia acquired and the center of the aequlsition target is determined, thereby also determlning a refer ence point on the data array. The analog aignal is aimultaneoualy dlgitized on a continuous basia by means of an analog-to-digital converter and atored in an image buffer. The atored digitized data representing the entire label ls available for further Processing in the decoding procesa. -11- LV 10820

By atored program logic circuita, the dlgital data la transformed into a map of the lnterfaces of hexagona having dif-ferent optical propertlea. In a preferred embodiment of the lnvention, thls la done by computlng the atandard devlatlon of the intenaitiea of the reflective propertlea recorded by the op-tlcal aenaor at each pixel and a predetermined group of plxels surrounding that firat pixel. High Standard deviations therefore correapond to tranaition areaa at the lnterfaces of contrasting hexagona.

Further data transformationa, involving filtering pro-grams to determine orientation, dlrectlon and apaclng of the hexa-gona, are performed on the dlgital data. The general steps of thia process are: (1) Filtering the non-linear transformed version of the digitized image. (2) Determining the orientation of the label, prefer-ably by locating the three axes of the image (as lllustrated in Fig. 2) and determining vhich axis la parallel to tvo sides of the label. (3} Finding the center of each hexagon and determining the gray Ievel at each center. (4) Tranaforming the gray Ievels to a bit stream. (5) 0ptionally, applying error correctlon to that bit· stream; and (6) Optionally, converting the bit atream to a pra-determined set of characters.

It la to be noted that. although the process of thia lnvention is described as applied to hexagons having two or more optical propertlea, the process, in particular, the steps for adjuating the optical image for label varp, tear and the like, may be applied to other types of labela and other polygonal celis.

Other objecta and further scope of applicability of the present lnvention vill become apparent from the Oetailed Deacrip-tion of the lnvention. It is to be understood, hovever, that the detailed description of preferred embodimenta of the lnvention la -12 5 given by vay of illustration only and is not to ba eonatrued as a limitation on the scope of variations and modifications falling vithin the apirit of the invention, as made apparent to those skilled in the art.

BRIEF DESCRIPTION OF THE DRAWļŅCS FIC. 1 la a plān view of an acquisition target of concentric rings in accordance with the present invention. FIC. 2 is a fragmented plān view of an optically-readable label having contiguously-arranged hexagons for encoding data in accordance with the present invention. FIC. 3 is a plān viev of a complete optically-readable label having contiguously-arranged hexagons of three optical propertiea 15 for encoding binary data and including an acquiaition target, in accordance vith this invention. FIC. 4 is a plān viev of a three celi by three celi cluster of contlguous hexagons, vhich may serve as the basie encoding unit of the preferred embodiment of this invention. 20 FIC. 5 is a cluster map shoving a graphic representation of a data array comprising 33 rovs and 30 columns, forming a grid of 11 rovs and 10 columns of three celi x three celi cluster coding* units of hexagons. 25 FIC. 6 is a schematic viev of a camera adjusting system in accordance vith the invention for adjusting the position of the optical light sensor in accordance vith the height of package being sensed. 30 FIC. 7 is a detailed outline of the decodlng process of this invention. FIC. 8 is a flov* chart shoving the acquisition target location process. -13 35 LV 10820 FIO. 9 is * flov chart ahovlng the encoding and decoding program atrūcture and data flov. FIO. 10 la a flov chart ahovlng the aequence crf lmage proceaaing steps.

S FIG. 11 is a plān viev of a cluster of contiguous regular hexa-gons arranged vith the geometric centers of adjacent hexagons lying at the vertices of a regular hexagonal array. 10 FIO. 12 la a plān viev of a cluster of contiguous irregular hexa-gons arranged vith the geometric centers of adjacent hexagons lying at the vertices of an irregular hexagonal array. FIG. 13 is a plān viev of a cluster of partially contiguous poly-15 gona aubstantially in the form of hexagona arranged vith the geometric centers of adjacent polygons lying at the vertices of a hexagonal array. FIO. 14 is a plān viev of a cluster of contiguous polygons sub- 20 atantially in the form of hexagons arranged vith the geometric centers of adjacent polygons lying at the vertices of a hexagonal array. FIG. 15 is a plān viev of an optically readable label having con-25 tiguous polygons substantially in the form of hexagons arranged vith the geometric centers of adjacent polygons lying at the vertices of a hexagonal array and including an acqulsition target in accordance vith this invention. 30 FIO. 16 is a plān viev of a cluster of contiguous eguilateral sguares arranged vith the geometric centers of adjacent squares lying at the vertices of a hexagonal array. -14 35 FIO. 17 ie a plān viev of a clueter o£ noncontiguous rectanglea defining interstitial apaces among said rectanglea with the geo-metrlc centera o£ adjacent rectanglee lying at the vertices of a hexagonal array. 5 FIC. 1Θ ia a plān viev o£ a cluater of noncontiguous pentagona defining interatitial apaces among said pentagons vith the geo-metric centera of adjacent pentagons lying at the vertices of a hexagonal array. 10 FIC. 19 ia a plān viev of a cluater of contiguous rectanglea ar-ranged in staggered rovs and columns vith the geometric centera of adjacent rectangles lying at the vertices of a hexagonal array.

1S FIC. 20 ia plān viev of a cluster of partially contiguous octagona defining interstitial apaces among said octagons vith the geometric centers of adjacent octagons lying at the vertices of a rectangular array. 20 2S 30 -15- 35 5 10 15 20 25 30

DETAILED DESCRIPTION OF THE INVENTIONIHS.IABEL LV 10820

The ability to encode Information by virtue of the con-trasting colors of contiguous hexagona or "čella" arranged in a honeycomb pattern in a predetermined sequenee and array permits the Information stored on the label to be recovered by an electro-optical eensor. Polygonal celis, other than hexagons, that are arranged with the geometric centera of adjacent polygona lying at the vertices of a hexagonal or other predetermined array, may likevise be used to encode Information on an optically readable label. Such polygonal celle, when arrayed with their respective centera at predetermined locations on a tvo-dimensional geometric array and when encoded in a predetermined aequence, through asai gning different optical properties to a plurality of auch poly-gonal čella, may be "read" by an electro-optical sensor and sub-sequently decoded in accordance with the procesa of the invention described belov. The polygonal celis of the invention are information eneoding units formed by a closed broken line, which celis are arrayed in a predetermined tvo-dimensional pattern on an opti-cally readable label. Label configurations employing a wide variety of polygonal shapes, and arrays of varying geometries, such as hexagonal, rectangular or sguare arrays, are usable in the practice of the invention. "Adjacent" polygonal celis may be totally contiguous, partially contiguous or noncontiguous on the optically readable labai of the Invention. "Contiguous polygona" are polygons arranged with the geometric centera of adjacent polygons lying at the vertices of a predetermined tvo-dimensional array and vith the bordera of such polygons touching the bordera of immediately adjacent polygons, leaving no interatitial apacea. "Partially contiguoua polygons" are polygona arranged vith the geometric centera of adjacent polygona lying at the vertices of a -16- 35 predetarminad tvo-dimenslonal array and vhich polygons ara sepa-rated somevhera along their respective borders from other surround-ing polygons, thereby causing a multipliclty of interstitial spaces to be interspersed among said polygons on the optically readabla labai. "Noncontiguous polygons" ara lndividual polygons arrangad vith tha geometrlc centers of adjacent polygons lying at tha verticee of a predetermined tvo-dimensional array, and having no contact betveen the borders of an lndividual polygon and poly-gons aurrounding said polygon. Additionally, tha polygonal celis and tha pradatarmined tvo-dimensional grids or arrays upon vhich the centers of adjacent polygons ara located may be irregular, having unequally-spaced axes, or regular, having equally-spaced axes,. in configuration. Such tvp-dimensional array axes may be independent of tha axes of symmetry, if any, of the polygonal čella.

Aa used in the labai of thia invention, hexagons pre-aant certain important advantagas for ancoding Information on a labai. Those advantagas ara: (1) For a given optical resolution, hexagons can be mora denaaly packed than other polygona. For example, at a given resolution, tha corners of squares are more difficult to resolve, so that othervise unnecessary optical resolution is required to "read" squares. Circlas vould be optimal for optical resolution, but tha space betveen adjacent circles vould be vasted and vould complicata tha Processing and printing of the label image, be-causa of tha need to aasign an optical property to the spaces. Hexagona permit optinum packing of Information, compared vith circlas or other polygons including, octagons, squares, triangles and the llke. Squares and triangles ara problems becausa of the sharp cornara they have. Circlas and octagons ara problems ba· causa of tha vasted space betveen adjacent circlas or octagons. (2) A grid of contiguous hexagons has three axes. By using a labai of a sguare or rectangular shape tha major axls of tha hexagon can be located by its predetarmined ralation to a side of tha labai. Thls location of the major axis of a hexagon -17- LV 10820 grid facilitates the reading of the data encoded in the hexagon by ita relation to that major axia.

Aa used herein, "label" lncludea a dlacrate unit, vith a aultabla adheslve backing, to be attached to a package or prod-uct, and the exterior surface o£ a Container or othar object on which optically-readable Information ia imprinted in accordance with thia invention.

Aa uaed herein, "optically-readable data arrayn or "data array" meana a pattern of contiguoue hexagona or other polygonal celle having two or more optical propertiea to encode, in retriev-able form, a body of data by virtue of the reapective optical propertiea of and spatial relationahip of the hexagons or other polygonal celis to each other. The hexagons or polygons imprinted to contain thia recoverable information are' referred to herein aa "information-encoded" hexagona or polygona, because of the manner in vhich the label encodes information.

The pattern of contiguoue hexagona vlth the maximum number of hexagon-to-hexagon interfacea for optimal reading and maximum information atorage denaity ia referred to as a "honey-comb pattern."

The contrasting reflective propertiea utilized to prir.t the individual hexagons or celis of the data array can be varied greatly vithin the apirit of thia invention. Aa used herein, "printing" meana depositing materiāls having predetermined optical propertiea on a substrāts, or changing the optical properties, as when "thermal" printing is used. "Printing" also includea the omisaion to depoait a material having a predetermined optical property on a portion of the substrāts, where the substrāts itself has a diatinct optical property. For example, in printing hexa-gonal celis in black and vhite, if the substrātā is vhite, then only black celis muat aetually be printed. Thus, as used herein, the vhite hexagonal čella are also vithin the definition of the tera "print" or "printed."

Aa used herein, "optical propertiea" meana light ab-sorption, reflection and/or refraction propertiea of čella -18 printed in different media. Where celle ara prlnted ln black (high density black ink), gray (half tonēs of black) and white (no printing on a vhite substrātā), aa la tha case ln the preferred embodiment of tha invention, tha invention ls aald to hava 5 three optical properties.

Aa used herein, and vith reference to Fig. 1, "plural-ity of concentric ringa" or "concentric ringa" 10 means two or mora concentric ringa 12, one of which ia the interior araa of a circular zone 15 defined by the smallest radiua "r" of tha rings. 10 Fig. 2 illustrates a portion of an electro-optically acannable label in accordance with tha principles of this invention. Aa aaen in Fig. 2, the labai comprises a multiplicity of adjacent printed hexagonally-ahaped celis, formed in a honeycomb pattern. Each of the individual hexagons ia designated by numeral 15 20, and comprises 6 equal sidee 22. The interior angles "a" of tha hexagon ara also equal, each of 120 degrees. In tha illus-trated embodiment, the hexagon haa a long vertical axis y-y and a horizontal axis x-x. The x-x dimension of tha hexagon 20 is some-what amaller than the y-y dimension of the hexagon 20 due to the 20 geometry of a regular hexagon.

In a preferred embodiment of the invention, aa ahown in Fig. 3, utilizing a label 30 having dimensions of approximately 1" by 1", there will be approximately 888 hexagons or celis 20 (taking into account the fact that, in the preferred embodiment, 25 the center of the label is occupied by an acquisition target 35 comprised of a plurality of concentric rings). Thesa contiguous hexagons 20 naturally form horizontal rowa "R", defined by imagi-nary lines 31, and vertical columns "C", defined by imaginary linea 33. In this example a one inch by one inch label haa a 30 total of 33 horizontal rowa "R" and 30 vertical columns "C" of hexagons 20. Each individual hexagon has a "diameter" of about 0.8 mm. There are more rows "R" than columns "C" in a sguare perimeter bounding a honeycomb pattern of hexagons, due to the geometric packing of the contiguoua hexagons. -19- LV 10820

Utilizing the hexagons illustrated in Fig. 2, it vill be seen that the hexagons are aligned in etaggered and overlapping vertical columns, with alternate vertically spaced hexagons having co-linear y-y axea. The y-y axes of spaced hexagons 20 are in alignment with an exterior vertical side 22 o£ an intermediate, displaced hexagon. The y-y axes of hexagons 20 are parallel to the two vertical borders 32 and 34 of the label, as depicted in Fig. 3. Horizontal rovs "R" are measured through the x-x axes at the mid-point of the hexagon 20.

As more fully described belov, the hexagons 20 are formed by a printing procesa vhich vill print the hexagons 20 in tvo or more optical properties, for example, contrasting colors. Those colors may be vhite 25, black 26 and also, optionally but prefer-ably, gray 27 aa illustrated in Fig. 3, although other contrasting colors may be utilized. It is possible to use only tvo contrasting colors, such as vhite 25, and black 26 as seen in Fig. 2. In the preferred embodiment of the invention, three contrasting colors are utilized, vhite 25, and black 26, and gray 27, illustrated in Fig. 3. The particular shades of vhite, black, and gray are selected to achieve optimum contrast for ease of identifieation by an electro-optical sensor. The gray Ievel is selected so that its optical properties fall approximately equally betveen the optical properties of the vhite and black being used in creating the label.

The label 30 of Fig. 3 may be formed by using a discrete label, having, in a preferred embodiment, a one square inch area, or, if an acceptable color background is utilized (preferably vhite), the label may be printed directly on a package surface, vithout requiring a discrete label. Secause of the importance of having a controlled optical property background for one of the contrasting colors, it is preferable to use a discrete label, because the color of the label background is more easily controlled.

The alignment of the hexagons printed on the label in relation to the sides of the label is important for subseguently -20- determining the major axia of the label aa doacribed below. The labai la printed ao that the y-y axea of the hexagona forming the honeycomb will be parallel to the vertical aldea of the label, 32 and 34, aa ahown in Flg. 3. 5 In "reading" the hexagonal array, in order to decode the Information contalned in the lndivldual hexagona, it la lm-portant to have a aharp color contraat betveen adjacent hexagona. For reaaona deacribed belov, the fever optical propertiea utilized to encode the hexagons, the aimpler may be the acanning 10 equipment and softvare necesaary to decode the hexagona. Hov- ever, fever optical propertiea alao decreaae the data denaity of the label. In a compromise betveen the amount of decoded Information capable of belng atored on the label and the coat of acanning multi-optical property labela, it haa been found deairable 15 to print the encoded hexagona vith three optical propertiea, namely the colora black, gray and vhite. If the aubatrate or label haa a good vhite background, then vhite hexagona can be created by the absence of ink, and only black and gray hexagons actually need to be printed. 20 In the preferred embodiment of the invention, the gray hexagonal celis are created by printing the čella vith black ink, but only every fifth pixel of the pixel grid of a dot matrix printer is so printed in the illustrative example deacribed herein. Thia is done by the use of a half-toning algorithm, in a 25 manner vhich ia veli knovn in the art. Thia allovs a printer to print a predetermined proportion of the pixels to define a given gray hexagon, vhereas a black hexagon requirea printing every pixel definlng that hexagon. The apecific half-toning algorithm used to print labela of che preferred embodiment ia contalned in 30 the aource code liatinga entitled "LABEL" in the Microfiche Appen-dix, page 29, llnea 39 to 48.

The black hexagonal čella can be formed by printing vith a Standard black ink. Aa deacribed belov, the acanning an-alyaia softvare of the decoding procesa makea groaa determina-35 tiona among black, gray and vhite reflectlvitiea, so that preciee -21 LV 10820 color definition ia not necesaary. On the other hand, if colors other than black, gray and vhite are used, or if various ahadea of gray are uaed, to create four or five color data arraya, the contraat of ink ahadea muat be much more carefully controlled to 5 enaure meaaurable optical property differencea among the various colora. It vill be appreciated that the use of black ink ia the simplest and easiest approach to creating a three optical prop-erty honeycomb array of hexagonal čella, and ia the preferred embodiment of the invention. 10 Becauae of the square shape of the label in the pre ferred embodiment and the nature of the hexagonal čella, the edgea of the honeycomb will contain incomplete hexagona 56; as aeen in Fig. 3 theae incomplete hexagona are not used to convey any use* fui Information. 15 In the preferred embodiment of the invention, the label alao containa an acguiaition target. The acquiaition target 35, aeen in Fig. 3, comprisea a plurality of concentric ringa of con-traating colora (ahovn aa black and white). The black rings are respectively designated 42, 46 and 48, and the vhite ringa are 20 respectively designated 44, 50 and 52. The target is preferably located in the geometric center of the label, to make it less susceptible to being damaged or destroyed, in vhole or in part, if the periphery of the label ia torn, soiled or damaged. Alao, the size of the image buffer (described belov), needed to store 25 the data from the label before the label target is identified, is minimized when the acguiaition target ia in the label center.

The number of concentric ringa uaed in the acguiaition target may be varied, but the aix concentric rings 42, 44, 46, 48, 50 and 52 and their reaulting interfaces aa they vary from 30 vhite to black to vhite, etc. , have been found to be convenient and deairable. A pattern correlating technigue ia used to match a com-puted pattern of what the concentric rings are expeeted to be vith the pattern being read. When the match occurs the acgulsi-35 tion target haa been located aa more fully described belov. The -22- apecific filter created and utilized in connection wlth the pre-ferred embodiment of the invention may be found in the Microfiche Appendix, page 41, linea 51 to 52 page 42, llnea 1 to Θ and page 40, linea 19 to 41 under the file name "FIND.C." 5 The acquiaition target may be of any overall diameter smaller than the data array, to provide an area vhich may be 25%, and ia preferably about 7%, of the area of the data array. Pre-ferably the acquisition target is aizēd aa amall aa poaaible aince the area it occupiea on the label cannot carry encoded Information. 10 In the preferred embodiment the diametera of the imprinted ringa are aelected ao that the outaide' boundary of the external ring 52 ia about 7.45 millimetera. Thua, in Fig. 3 the area of the acqui-aitioņ target 35 occupiea about 7% of the aurface area of the one square lnch label 30. In this vay, a aatiafactory acquiaition 15 target 35 may be imprinted on a one inch aquare label 30 vithout unduly interfering with the amount of information vhich can be encoded in the hexagonal array that aurrounda the acquisition target. Aa la the caae vith the incomplete hexagona at the outer periphery of the label 55, the fractional hexagona contiguous 20 vith the outer boundary of the acquisition target 56 are not utilized for the purpoee of encoding information. The vidth of each ring ia deairably about the aame aa the aide-to-aide (x-x axis in Fig. 1) dimenaion of the hexagona, to facilitate reaolution. SiA ringa are convenient. Thia ia a reasonable number to facilitate 25 location of the ringa in a minimum label area vith a minimum of poaaible falae readlngs from "spurioua" mārks on the label and other "apurioua" marka not on the label, auch aa mārks elaevhere on a conveyor belt.

The acquisition target may take shapes other than con-30 centric ringa. For example, aquares, apirala or hexagona may be used in order to create transitiona of contrasting concentric figurea, ao long aa linear aections through the acquiaition target vill create regular, predetermined and ldentlfiable color tranaitiona, auaceptible of being aenaed by an electro-optical 35 aenaor and meaaured by a aultable filter. It ia to be noted that, -23- LV 10820 although a spiral is not a collection of concentric circlee, de-pending on the size and radius of the spiral, a close approxima-tion of concentric circles can be achieved. A target of concentric rings is preferred, because the^ signal generated by a scan through their center has a frequency which is the same when sec-tions are taken in any direction through the center of the concentric rings. This makes Identification of the center simpler, aa more fully deecribed below, and allows Identification of the location of the acquisition target with a one-dimension search of the analog or digital output of the scar.ner, although the process of the invention may alternatively or subsequently utilizē a tvo-dimensional digital search for increased accuracy when a digital signal is being analyzed.

As used herein, "Concentric Rings" is intended to em-braee complete rings, partial rings in the form of semi-circles, sectors of concentric rings occupying betveen 180 degrees and 360 degrees and concentric spirals which approxlmate concentric rings.

Since each hexagon may be encoded in three different optical properties, in the preferred embodiment, 1.585 "bits" of Information may be encoded in each hexagon (log ^3 ) . 0bviously, if fewer or more optical properties than three are utilized, the number of bits encoded in each hexagon will vary commensurately. The encodlng algorithm is structured to achieve close to maximum data density and to increase the number of cell-to-cell optical property transitions, in order to facilitate the two-dimensional clock recovery process described below.

Figurē 4 illustrates a 3 celi x 3 celi cluster of nine hexagonal celis 60, the basie encoding unit utilized in the preferred embodiment of the invention. This is a desirable encoding approach, but is not essential. Other encoding units are feasible, vithin the purviev of the Invention. As more fully described belov, the 3 celi x 3 celi elusters of hexagons 60 are mapped to encode 13 bits of information if the cluster contains a full complement of 9 hexagons, or less than 13 bits if the cluster is incomplete by having unusable hexagons. In a one inch sguare -24 label vith a data array comprleing about 888 hexagons and an acquisition target occupying about 7 percent of the label area, about 1292 bits of Information may be encoded.

In encoding each cluster, external, bottom hexagons 62 5 and 64 in each cluster 60, as seen in Fig. 4, are limited in their respective optical properties, so that they are determined always to be different from intermediate and contiguous hexagon 66.

Thus, only one bit per hexagon can be encoded in hexagons 62 and 64. In this vay it is possible to encode 13 bits of information 10 in cluster 60 by encoding 11 bits onto the remaining seven hexa-gons, Since mapping 7 hexagons provldes more possible combina-tions than are utilized (ι . e, , 3’=2187 combinationa vs. 2n=2048 combinations), some combinations are rejected as, for example, ali black, ali gray, ali white or subatantially ali black, gray 15 or vhite combinations. The reasons for requiring contrasting colors of hexagons 62 and 64, compared to hexagon 66 are to guar-antee transitions necessary for the clock recovery step and op-tional normalization process step described belov and to assist in determining horizontal alignment of the data array, as described 20 belov. In cases vhere encoding clusters have 7 or 8 hexagons, 7 usable hexagons are encoded vith 11 bits and the eighth hexagon, if available, is encoded vith 1 bit. For ali other partial clusters 3 bits are encoded on every pair of hexagons and 1 bit onto* each remaining single hexagon as more fully described belov. 25 It vill therefore be seen that the label constitutes a particularly efficient, easy-to-read (by means of appropriate scanning eguipment and analytical softvare) label for encoding a very high density of information into a relatively inexpensive, easy-to-print label. As noted, the prefeLred embodiment utilizēs 30 a 33 rov x 30 column packing of hexagona into a one square-inch label, vith an acquisition target representing approximately 7% of the total eurface area of the label. In practice, 13 bits of *

Information are obtained from a cluster of 9 hexagons, so that 1.44 bits of data are derived per celi. This is less than the 35 25- LV 10820 theoretical 1.585 bite per hexagon because of the other con-atraints of the encoding algorithm, since ali 3’ patterns are not used, and some of the least optically desirable cell-to-cell traneitions are eliminated.

For reasons described below, in the preferred embodi-ment of the invention, it is desirable to incorporate a certain amount of error protection into the encoding of the label, so that the actual amount of recoverable Information in the label is reduced in favor of a high degree of data integrity in the decod-ing process.

As may be readily appreciated by one skilled in the art, the foregoing discussion of label embodiments enploying hexa-gonal celis is directly appiicable to optically readable labels utilizlng other polygonal celis. The disclosed methods of "print-ing" optical properties of hexagons apply equally to printing the optical properties of other polygonal celis, vhether in black, white, gray (through half-toning) or other colors. Similar con-straints and advantages as to data density enure to labels printed vith polygonal celis other than hexagons when the optical properties black ar.d white, and optionally gray, are utilized to print the polygonal celis. As vith hexagon-containing labels, labels printed vith other polygonal encoding celis may be "read" vith scanning eguīpment of less complexity vhen only tvo optical prop* erties are utilized to encode Information in the polygonal celis, in particular the colors black and vhite, because of the maximum contrast that is obtained vith these colors.

Information encoding proceduree and the algorithm described for hexagon-containing labels are directly appiicable to labels printed vith different polygonal celis. SimJlar to hexagon-containing labels, incomplete polygonal celis vhich may appear at the border of the optically readable label or that result from partial obliteration by the acquisition target, comprising a series of concentric rings are not used to encode infonnatlon. A "honeycomb pattern" comprises an array of contiguously-arranged hexagons 310, the geometric centers 311 of 26 vhich likevise Īle at the vertices 311A of a "hexagonal grld" or Mhexagonal array" 312, as shovn in Fig. 11. Regular hexagons, 1. e. hexagons having six equal sides and six egual interior an-gles, form hexagonal arraya that are likevise regular ln con-$ figuration, having three equally-spaced axes (AI, A2 and A3) that are spaced 60 degrees apart.

If the hexagons 320 of the label are irregular, but syrrji\etrical, as for instance, if the hexagons are stretched along two parallel sides 321, 322, the geometrie centers 32S of adja-10 cent hexagons will describe an irregular hexagonal array 327, as shown in Fig. 12. Such an irregular hexagonal array will stili have three axes {AI, A2 and A3), hcvever, the three axes will not be equally spaced 1.e. the three axes will not ali be 60 degrees apart. 15 Although the hexagonal array of Fig. 12 is not regular in nature, it is nevertheiess a two-dimensional geometrie grid or array having axes of predetermined spacing. Thus, the locations and spacings of the geometrie eenters of the hexagons located at the vertices of the intersecting axes of the hexagonal array are 20 also predetermined. The geometry of the hexagonal array is then utilized in the decoding process deseribed below. Specifically, the filtration step, performed on the transformed digital data corresponding to the image sensed by the optical sensor, is adjusted to reflect the predetermined label geometry, so that the 25 digital representation of the sensed label can be used to precisely reconstruct the original grid. The reconstruction process further supplies the missing points from the hexagonal grid. The missing grid points occur because optical property transitions did not take plača betveen polygons of like optical 30 properties.

With irregular hexagonal grids of the type disclosed in Fig. 12 it vill be desirable to adjust the major axis deter-mination step, step (3)(e) of Fig. 7 of the decoding process dona after the Fourier transformation step of the process to 35 -27 LV 10820 identify the major axis of the optically readable labai. The major axis o£ the labai will hava the geometric centers of poly-gons lying along this axis at different spacings than on the other tvo axaa. S Labai configurations of the invention approximating the praferred ambodiment containing hexagonal celis as described abova ara possibla using cartain polygonal celis. Figurē 13 il-lustrates a label configuration utilizing polygonal celis 330 which substantially resemble hexagons, but vhich ara 20-sided 10 polygons, rathar than hexagons. Similarly constructad polygcns with mora or lesa than 20 sides could also be printed. Polygor,s * 330 ara partially contiguous unlika the imaginary contiguous hexagonal celis 331 in vhich they are depictad.

The interstitlal spaces 332 of the Fig. 13 labai em-1S bodiment may or may not ba printed with a different optical prop-arty than the ancoded polygons. Interstitial spaces do not carry encoded Information, therefore, their presence leads to a lover data density for a given optical resolution and performance Ievel. Further, if the interstitial spaces dispersed among polygons are 20 of a different optical property than the adjacent polygons, more transitions betveen the optical properties of the polygons and the interstitial spaces could be sensed by the optical sensor ar.d thus a higher clock signal er.ergy vould appear in the transform domain vithin the decoding process described in detall belov. 25 Because the polygons of the Fig. 13 label are arrar.ged on a hexagonal grid having three egually-spaced axes, the gecmet· ric centers 333 of the polygonal celis 330 lie at the vertices of hexagonal array 335. The spacing, location and spatial orientation of the center' of the polygons are predetermined and 30 can be detected in the transform domain of the decoding process. 28- 35

The Fig. 13 label utilizēs polygona substantially in the form of hexagons. Because they so closely approximate a 5 hexagon, the optical sensor at a moderate resolution could "read" them as hexagons. The geometric centers 333 of the polygons 330 do Īle, hovever, at the vertices of the three equally-spaced axes (AI, A2 and A3) of the hexagcnal array 335.

Fig. 14 illustrates a eimilarly shaped (to polygon 330 10 in Fig. 13) polygonal figurē 340 that has been arranged to be totally contiguous. These ’p°iy9°na 340 can be approximated by an imaginary hexagon 341, as in Fig, 13, but no interstitial spaces (332 of Fig. 13) may be found betveen the actual polygons. Such a contiguous arrangement is desirable to aimplify the decoding 15 process, but ls not mandatory, in the practice of the invention. Polygons 340 are shovn vith their respective geometric centers 342 lying at the vertices of a hexagonal array 345. Again, as for the polygons 330 in Fig. 13, polygons 340 are substantia1ly in the shape of hexagons, and at a moderate optical resolution 20 would appear to be hexagons.

Fig. 15 is a blovup of· a label as it vould appear if printed vith a dot matrix printer printing 200 pixels per inch. Polygons 360 of Fig. 15 illustrate the shape of the geometric figurē that vill actually be printed in place of a hexagon vith 25 such a dot matrix printer, because of the pixel density of the printer. Printera vith greater pixel densities should yield closer approximations of a hexagon than the polygons 360 shovn on Fig. 15. Thus, polygons 340 of Fig. 14 and 360 of Fig. 15 are likely resulting shapes, due to the inherent limitations of • 30 certain printera, of the printing process for labais containing hexagonal celis or result from deliberate efforts to print such polygons -29- 35 LV 10820 8ubatantialiy in the form of hexagona in the first instance. Th· shape of such polygons substantially in the ahape of hexagons allov them to function, in a practical sense, as eguivalents of contiguous hexagonal encoding čella.

Aa in the case of Fig. 3, the optically readable label of Fig. 15 also contains an acquisition target 370 compriaing a series of concentric rings 371 through 376. Like the hexagons on the label of Fig. 3, the polygons 360 aubatantially m the form of hexagona in Fig. 15 are arranged in columns "C" and rova "R," as bounded by imaginary lines 361 and 362 and 363 and 364, respectively. Also, as in the case of the hexagons of Fig. 3, the polygons of Fig 15 have their respective geometric centers lying at the vertices of a hexagonal array as defined by equally-spaced axea AI, A2 and A3. Thua, labais of the config-uration ahovn in Fig. 15 are readily encoded and decoded in ac-cordance with the processes discloaed hereinbelov.

If an alternative label geometry is employed such as utilizing a aguare or rectangular array, or the like, adjustments must be made in the tvo-dimensional clock recovery process de-scnbed belov. The difierent geometry of the predetermmed array requires changes to be made in the filters utilized in the filter» ing step of the tvo-dimensional clock recovery process. The fil-tera operate on the transformed digital data correspondrng to the optical properties of the polygons read by the sensor in the image domain. Such minor adjustmenta to the filtration acheme could easily be made by a person of ordinary akill in the art. In situ* ations vhere the predetermined tvo-dimensional array has unequally-apaced axes, or is irregular in configuration, it may be desirable to identify the major axis of the label prior to performing the Fourier tranaformation of the digital data representing the opti-eallV aensed image. This ia beeause the geometric eentera of the polygona are not equally spaced along the axes.

Noncontiguously-arranged polygons can also be utilized to create an optically readable label in accordance vith the -30- present invention. Fig. 16 illustrates a hexagonal array of squarea 420, which are noncontiguously arranged with their respective geometric centers 422 lylng at the vertlcea of a hexa-gonal array formed by the three equally-spaced axes AI, A2 and A3. It is apparent that the configuration ls a hexagonally-based configuration from the grid of imaginary hexagons 421 which can be overlaid upon the polygons 420, thereby forming interstitial spaces 425.

Similar arrays to the šguare 420 shovn in Fig. 16 may be constructed using rectangles. Fig. 17 illustrates a multi-plicity of rectangles 430 arrayed with the geometric centers of adjacent rectangles lying at the vertices of a hexagonal array formed by intersecting axes AI, A2 and A3. Again, visualization of the hexagonal arrangement is aided by the imaginary hexagons 431 in Fig. 17 overlaid upon the noncontiguous rectangles 430, thereby creating interstitial spaces 435 betveen rectangles 430. Fig. 18 likevise ill'ustrates a noncontiguously»arranged label comprising pentagons 440 having the geometric centers 442 of adjacent pentagons 440 lying along the three egually-spaced axes AI, A2 and A3. The geometry of the noncontiguous pentagons is more easily visualized by overlaying the pentagons 440 vith imaginary hexagons 441, thus forming interstitial spaces 445 between pentagons 440.

Alternative hexagonal arrays may be constructed whore the axes of the array AI, A2 and A3 are equally spaced, but do not correspond to the axes of symmetry of the polygcnai figurēs themselves. Instead, the geometric centers of adjacent polygons lie at the vertices of the intersecting axes of the array. Such an arrangement is illustrated in Fig. 19, comprising a series of contiguous rectangles 450, having the geometric centers 451 of adjacent rectangles lying along axes AI, A2 and A3.

Higher order polygons may be similarly arrayed on a predetermined two-dimensional grid. Fig. 20 shovs a series of partially contiguously-arranged octagons 460 defining a multi-plicity of interstitial spaces 461 among said octagons 460. The centers 462 of adjacent octagons 460 are located at the vertices -31- LV 10820 o£ intersecting axes AI and A2, thue formlng an array of octagons 460, whlch may be used in the practice of the invention. Inter-stitial spaces 461 may be printed vith an optical property differ-ent than is used for octagons 460. Hovever, this is not mandatory in the practice of the invention, since it is the location, ori-entation and intensity of the optical property at the center of the octagons 460, lying at a predetermined position on the hexa-gonal array formed by axes Al and A2, that is most important in the decoding process.

It will be appreciated that although a preferred embod-iment of the label has been disclosed and described, many varia-tions of the label are possible vithout departing from the spirit or ecope of this invention. For example, the label need not be one-inch sguare. One square inch was selected as a reasonable size of label, to achieve an acceptable data density of 100 alphanumeric characters of Information vith a high degree of error 32- protection applied thereto, without creating an excessively large size label. It is desirable to have a one square inch label, to reduce the paper and other costs associated vith the printing, shipping and handling of such labels. ConventionaI bar code S labels of aimilar size would have a radically decreased data den-sity. Using 4, 5 or more optical properties or colora to define the hexagons will allow substantially more Information to be packed into a given space of hexagons of pre-determined size, but with a resulting mcrease in the complexity of the softvare and 10 senaitivity of the acanning system required in order to be able to recover that Information. Thus, for practical purposes, a three optical property, black, gray and vhite, encoding ayatem of optical properties is highly desirable. Also, the sizes of the hexagona and acguisition target may be varied widely vithin the 15 epirit and acope of this invention.

Although "clustering" of hexagons in 3 celi x 3 celi cluaters haa been described, other patterna of clusters may be uaed or cluatering may be omitted entirely and the encoding algo-rithm may be directed apecifically to an individual hexagon pat-20 tern. Also, the relative amounts of encoded Information devoted to the message as opposed to error correction may also be varied vithin vide limits vithin the spirit and scope of this invention.

LABEL ENCODING 25 Described belov is the encoding process of this inven tion, as applied to the preferred label embodiment. It vill be understood that the preferred embodiment is being disclosed and that numeroua combihations, variations and permutations are fea-sible vithin the purviev of this invention. 30 The process may begin vith a predetermined series of data desired to be encoded on a label. In a preferred embodiment, the label is a shipping label, and the data is broken into tvo fields, identified as a "high priorlty message" and a "lov pri-ority message." It vill be understood, hovever, that the inven-35 tion is not restricted to tvo different messages or Ievels of -33 LV 10820 priority. Many meesages and Ievels o£ prlority may be created vithin the quantitative limits o£ a labsi of given Bize and num-ber of celle.

For example, where the label is intended as a shipping 5 label, the "high priority message" may constitute nine characters, representing the zip code of the recipient of the intended pack-age, pārcel or letter. Nine digits is referred to because, al-though many individuāls and companies have five digit zip codes, nine digit zip codes are being used vith increasing frequency. Therefore, in handling packages for delivery, the most important piece of Information is the zip code. This determir.es the general destination of the package and allows various scannmg and pack-age control systems to be used to direct the package to the proper destination on trucks, aircraft, in a conveyor system and the 15 like.

The lov priority message may, for example, include the name and shipping address, including zip code, of a recipient of the intended package, as well as billing Information. 20 25 30

The reason for creating a high prionty message and a lov priority message is to protect the high priority message vith extra error correction, to allov the high priority message to be placed (encoded) in a more central area of the label, vhere it is less likely to be damaged or destroyed, and to permit the high priority message to be repeated and distributed in the lov pnorit message so that, even if the high priority message is selectively destroyed, there is a high possibility that the high priority message can be retrieved from the lov priority message. 3y locat-ing the high priority message in a central area, it may only be necessary to decode the high priority meoaage for some purposes, so that only a portion of the label needs to be processed, thus speeding up processing time. This Vili occur, for example, vhen a pārcel is on a conveyor and only the zip code neada to be deter-mined to control vhich of several conveyor paths the pārcel should take in the handling process. 34 35

Becauae it ia of a lower priority, the low priority message ia not presented tvice on the label. Hovever, as describec belov, both the high priority and the low priority meaaages may incorporate various error protection codea and correction capabili-5 ties, in order to maximize the likelihood that both meaaages may accurately be retrieved.

The use of error protecting characters as part of the encoded Information can, in the preferred embodiment of thia invention, in combination with an appropriate stored program and com-10 puter, cauae the system to correct an error during the decoding procesa, in the manr.er described belov. The use of error protecting codea ia veli knovn in the art and ia vithin the purviev of the akilled peraon in the art.

In the practice of the invention an operator creating a 15 label may manually input the data to a suitable Computer termiņai vhich ia deaigned, in the manner described belov, to activate a printer to print a label vith the high priority message and the lov priority message suitably encoded in the hexagona of the label It ia not essential to the invention that a high priority message 20 and a lov priority message be created, but it ia desirable in order to maximize the likelihocd that the most important data to be encoded vill be retrieved. In the preferred embodiment the label ia also printed vith a centrally-located acquisition target compriaing a plurality of conce.ntric rings of tvo alternating 25 contrasting colors, the colors preferably being tvo of the coiors utilized to print the individual hexagons, and moat preferably black and vhite to ensure maximum contrast.

The operator manually inputting thia data vill cauae a suitably programmed compute. to encode each character of the input 30 message and use suitable field designators, in order to create, in the operated Computer, a binary bit atream, representing the characters of the message and suitably encoded by field to desig-nate the high priority and lov priority messages and the relative poaition of each. Thia operation ia carried out by the program 35 "ΤΕΧΤΙΝ.0" vhich may be found in the Microfiche Appendix, page 1, -35- LV 10820 lines 8 to 54; page 2, lines 1 to 54; and page 3, linee 1 to 36; and 19 designated 110 on Fig. 9. A Computer vith the required features may be a Compaq Deskpro 386 (vith a 16-MHz clock and an Intel 80387 math coprocessor chlp).

AlternativeTy, the process may begin vith the Information to be encoded already contained in a binary bit streara, because, for example, it vas received from a storage medium or othervise created. Therefore, the message to be encoded can exist in a form vhich is manually (vith electronic assistance) converted to a binary bit stream or vhich begins as a binary bit stream.

Once the binary bit stream has been created or an error-protected bit stream has been produced by the steps discussed more fully belov, the bit stream must be mapped in accordance vith a predetermined mapping pattern for the encoding of the hexa-gon honeycomb of this invention. Fig. 5 is a "cluster map" vhich shovs the individual hexagonal celis of 3 celi x 3 celi clusters aligned in a grid or honeycomb containing 33 rovs and 30 columns of hexagons. Each rov is nunbered, and each column is numbered. The rov numbers range from 1 to 33, and the columns range from 1 to 30. It can be seen that certain of the hexagons designated along the upper surface and right-hand surface of the region map, and vithin the geometric center of the grid are designated by X's. This indlcates that these hexagons do not contain bit-mapped Information. This is because the exterior X's represent partial hexagons at the edge of the label, thus causing each of these rovs to each have one fever hexagon. The interior hexagons designated by X's represent spaces either occupied by the acquisition target or incomplete hexagons around the perimeter of the acquisi-tion target, so that these interior hexagons indicated by X's are not bit-mapped. Ali of the hexagons vhich are not identified vith X's are capable of recording information. In accordance vith the preferred embodiment, each of these spaces vill be occupied by a black (B), vhite (W) or gray (C) hexagon. As noted above, although various clustering and mapping techniques can be utilized, the application of this invention may use clusters of 9 -36- hexagons in 3 rows of 3 hexagons each to define specific bite o£ Information, and, as also described above, 13 bits of Information are desirably encoded in each such 9-hexagon cluster.

In a data array comprising 33 rows and 30 columns of contiguous hexagons, a grid of 11 rows by 10 columns of hexagon clusters each containing a 3 celi x 3 celi arrangement of contiguous hexagons, is formed and may be visualized in connection with Fig. 5. It vill be appreciated hovever that every row of 3 celi by 3 celi clusters vithin the 11 cluster x 10 cluster grid vill contain a cluster of either 7 or 8 hexagons because of the geometric packing of hexagons, and the number vill alternate from rov to rov. Thus, 6 clusters containing 8 hexagons and 5 clusters containing 7 hexagons result from this arrangement. Also, the centrally located acquisition target creates additional in-complete clusters. Fig. 5 thus provides a graphic representation of usable clusters of hexagons available for encoding vith bits of Information in a 33 rov by 30 column data array of contiguoua hexagons.

With reference to Fig. 4, clusters vith nine usable hexagons are encoded utilizing the folloving algorithm:

Take eleven bits of information and map them into the set of seven hexagons identified as a, b, c, d, e, f and h.

Hexagons g and i are used to represent 1 bit each in such a vay as to guarantee that each of them is different from hexagon h.

Thus, thirteen bits of information are encoded in a complete 3 celi x 3 celi cluster of nine contiguous hexagons.

For partial clusters of 7 or 8 usable hexagonsi

Take eleven bits of information and map them into the set of the first seven usable hexa-gons.

The eighth hexagon, if available, is used to represent one bit.

For ali other partial celis:

Map three bits of information into as many pairs of hexagons as possible. -37- LV 10820

Any remaining single hexagons are used to represent one bit.

Since mapping seven hexagons provides more connbinations than eleven bits (i.e., 3’ = 2187 vs. 2^ = 2048), soma combinations S of the hexagons need to be rejected. The rejected combinations are chosen to be those that provide the ievest number of transi-tions. To implement this, look-υρ tables vēra created to map the clusters in accordance vith Fig. 5. The creation and use of these look-up tables is vithin the capabllities of a skilled 10 programmer. With reference to Fig. 9, the program for creating the look-up tables "BINHEX.LUT" 132 and "ΗΕΧΒΙΝ.LUT" 134 may be found in the Microfiche Appendix, page 4, lines 3 to S2; page 5, lines 1 to 53;. and page 6, lines 1 to 34, and is ider.tified as "MK ΗΕΧ LUT" 130, IS Use of this bit allocation scheme allovs 1292 bits of

Information to be encoded in a 33 row x 30 column data array of contiguous hexagons.

The sequence in vhich the high priority information and low priority information is located throughout the cluster map is 20 predatermined, depending upon: (a) The size of the high priority message; (b) The size of the lov priority message; and (c) The optimum location for the high priority message in a protected place. 25 Utilizing the cluster map as illustrated in Fig. 5 as a template, a stored mapping program "MKMAPS.C" 140 operating on the digital data contained in a storage medium makes a predeter-mination of hov to distrlbute the information -- both the high priority message and the lov priority message -- throughout the 30 cluster map, as more fully described belov. The mapping program is identified in the appended source code listings as nMXMAPS.C" 140 and may be found in the Microfiche Appendix, page 19, lines 3 to 53; page 20, lines 1 to 53; page 21, lines 1 to 53; and page 22, lines 1 to 42. 38 35

In order to minimizē the likelihood of error, and be able to correct errors, the preferred embodiment of the invention desirably includes extensive error protection and correction capa-bilities. For example, in a preferred embodiment having 1,292 bita of information able to be encoded in a one sguare inch array of hexagona having 33 rows x 30 columns of hexagons, and an acqui-sition target occupying about 7¾ of the label area, it is deairable to utilizē 36 high priority message information bits to encode a 9-digit zip code plus one additional alphanumeric character, which may represent a shipping code. In this example, it vould also be deairable to use 120 check bits for the high pnority message.

Thia ia determined by the amount of error correction capability desired. Similarly, in the illustrative embodiment, 560 bita of low prionty message are included; this includes 40 bits of high priority message vhich is incorporated in the low priority message. In the example, 576 low priority message check bits vill be added in order to maintain the security and facilitate recov-ery of the lov priority message. This example illustrates the much more lavish use of check bits in order to preserve and per-mit recovery of the high priority message as opposed to the low priority message. It is to be understood that the foregoing Information is by way of example only and that the high priority message could be longer or shorter, the lov priority message longer or shorter, and the number of check bits greater or iever, depending upon the particular application of the invention. A "systematic code" takes a specific message seguence and adds a distinct error check seguence to the message sequence. A Nnon-systematicn code takes a specific message sequence and incorporates the error check sequence vith the message seguence so that the message is no longer distinct, but is, of course, recoverable. It is vithin the purviev of this invention to use either systematic or non-systematic coding for error protection.

The disclosure belov is of a eystematic code. -39- LV 10820

As defined herein, the step of "interposing error de-tection symbols" includes systematic and/or non-systematic coding aystems.

Varioue systematic linear cyclic error protection codes 5 are knovn in the art, for example, BCH codes, Reed-Solomon codes and Hamming codes. In a preferred embodiment, Reed-Solomon codes are separately incorporated to protect the integrity of the high and low priority messages. Reed-Solomon codes are very efficient and most useful when multi-bit characters are being error-checked. 10 Reed-Solomon codes are well knovn and it is to be understood that this is simply a preferred embodiment, although many other error correcting codes could be utilized in the invention. Reed-Solomon and other coding systems are discussed in, for example, Theorv ar\4 Practice of Error Control Codes. Richard E. Blahut, Addison 15 Wesley, 19Θ3, at pages 174 and 175.

By vay of example, some relevant Information about the Reed-Solomon code is set forth below. Specific characteristics of a Reed-Solomon code can be specified by the folloving param-eters: 20 m = number of bits in each symbol n = number of symbols in the block = 2m-l k = number of message symbols (number of message bits * km) t * correction capability in number of symbols = (n - k)/2 λ nine-digit zip code and single alphanumeric charac-25 ter for further identification purposes requires 36 bits vithout error protection in the example described below. A Reed-Solomon code with the following parameters was chosen for the high priority message. m = 6,(6 bit symbols) 30 n 26 - 1 * 63 t = 10

Therefore, k » n - 2t * 43

Since only six 6-bit symbols are reqfuired to rapresent a 36-bit message, the remalning 37 symbols (43-6) are padding symbols, which are implied betveen the encoder and the decoder, -40 and neēd not be atored on the label. Thus, the total number of bits required on the label for the high priority message is (63 -37) X 6 or 156 bits.

This error coding scheme will be able to correct a maxi-5 mum of up to 60 (10 x 6) bit errors, vhich amounts to 38.5¾ of the bits used. Due to the large number of implied padding sym-bols, the large error detection capability of this Reed-Solomon encoding makes it extremely unlikely that the high priority mes-sage will be read erroneously. 10 The low priority message was encoded vith a Reed-Solomon error protection code having different parameters, namely: m = θο(8 bit symbols) n = 2® - 1 = 255 t = 36 k * n - 2t = 183 15

Since there are 1292 bits available for encoding on the label according to this illustration, a total of 1136 bits (1292 - 156 high priority message bits and check bits) are available for encoding and check bits for the low priority message. Thus, the remaining 904 bits (255 x 8 - 1136) have to be implied padding 20 bits. This allovs 560 .bits ( 183 x 8 - 904) for the Information content of the lov priority message and 576 check bits.

To further ensurs recovery of the high priority message it is also included in the low prionty message. The Reed-Solomon error protection code applied to the lov priority message permits 25 encoding of an additional 86 6-bit alphanumerie charaeters and has a maximum error correction capability of about 25.4%.

Utilizing the foregoing Reed-Solomon error protection encoding, the total number of 1292 bits of Information available on the illustrative label are distributed as follovs: . 30 36 high priority Information bits 120 high priority check bits 560 lov priority Information bits (including 40 bits of high priority message incorporated in the lov priority message) 576 lov priority check bits 35 The bit stre&m of data, including the appropriate check bits for preserving the information, are assigned to individual -41- LV 10820 hexagons on the cluster map of Fig. 5. It will be appreciated that a vide variety of distribution patterns can be utilized, recognizing that the important criterla to be determined are! (1) eafe location of the high priority message prox-imate the acquisition target (if present on the data array); and (2) creating a pattern vhich is reasonably easy to reassemble vhen reading occurs.

The apecific error coding program employed īn the 11-luatrative example ls contained in the Mlcrofiche Appendix under the program "ERRCODE.C" at page 15, llnee 1 to 52 and page 16, lines 1 to 50,

Encoding for Reed-Solomon codea requires multiplication of the message code vector vith a generator matrlx. The matrix multiplication ls done using Calois Fleld ar'ithmetlc. Addition of any tvo elements of the fleld is obtained by performing an excluslve "or" operation betveen the tvo elements. Multiplication is performed via a "log" operation in the Galois Field. The log and antilog are obtained by using look-up tables generated from prime polynomials, specifically for the high priority message: 1 ♦ x*; and for the low priority message: 1 ♦ x* ♦ x* ♦ x* * x‘. With reference to Fig. 9, an auxiliary program "GF.C" 126 generates the look-up tables necessary for the Galois Field arithmetic. Auxiliary program "GF.C” may be found vithin the Mlcrofiche Appendix at page Θ, lines 1 to 53 and page 9, lines 1 to 32. The look-up tables are computed and stored in the file "GF.LUT" 127 for use during encoding and decoding. The generator polynomial g(x) for the Reed-Solomon code is determined by the folloving equation: g(x) » (x ♦ a) (x + a*) ........ (x * a2t) vhere a is the primltive element of the

Galois Field.

The generator matrix for the Reed-Solomon code is formed by performing a long divislon for each of the rovs of the generator matrix. The kth rov of the generator matrlx is given by the 42 remainder obtained from performing a long division of xn"*'** by β(χ>.

Th· computation of the generator polynomials g(x) aa veli as th· generator matrices for both the high priority and low priority messages is implemented according to the auxiliary pro-gram "MXRSLUT.C" 125, vhlch may be foand in the Microfiche Appen-dix, pag· 10, lines 1 to 52; page 11, lines 1 to 53; page 12, lines 1 to 54; page 13, lines 1 to 52; and page 14, lines 1 to 4, The look-up tables for the generator matrices are generated and stored in the file. "RS.LUT" 128.

In a preferred embodiment of the invention, labels con-taining hexagons are printed vith Standard printing eguipment that is readily available and inexpensive. A printer having a 300 x 300 dot matrix per square inch capability viil yield satis-factory results for printing three-color (black, gray, vhite) labels having 888 hexagons plus a centraily-located acquisition target. A printer vith these capabilities is the Hevlett Packard Laser Jet Serles II vith 0.5 megabytes of memory and a 300 dot per inch graphics resolutlon. A 300 x 300 pixel grid having a density of 90,000 pixels per sq\iare inch producēs about 90 plxels per hexagon in the preferred embodiment. Each pixel is assigned a value of 0 or 1, representing a black or vhite pixel. This printer is utilized to print a tvo-color data array of black or vhite hexagons. It may also be used to print a three-color data array of black, vhite and gray hexagons if a half-toning algonth' is utilized to producē gray hexagons, as previously described.

Referring to Fig. 9, by means of a stored program "MKMAPS.C," 140 a reģions look-up table "REĢIONS.LUT" 141 of 34 rovs x 30 column*· vas created, vhich is analogous to Fig. 5, but vhlch vas adapted to designate selection of black or vhite for the acgulaition target rings. Individual hexagons are coded for black, vhite or gray or as unusable. A separate look-up table "ΗΕΧ MAP.LUT" 142 vas created by a stored subroutine of the program "MKMAPS.C" vhich specifies allegiance of each of the 300 X 300 pixels on the pixel grid to specific reģions in the -43- LV 10820 "REĢIONS.LUT" 141, 1.e.. about 90 pixela per hexagon. Pixels be-longing to the finder rings are coded for either black or vhite. Acquisition target rings ara printed by first generatlng a hex-agonal pattern on each reglon row then generatlng the rings.

Reģions partially or completely covered by the finder rings are rendered unusable in the "REĢIONS.LUT" 141. The foregoing program "MKMAPS.C" and subroutines may be found in the appended source code in the Microfiche Appendix, pages 19 through 22.

The error protection encoded bit stream is mapped in accordance vith a predetermined sequence into the 11 x 10 cluster array of hexagons. Stili referring to Fig. 9, the sequence is specified by an order look-up table "ORDER.LUT" 151 generated by an auxiliary stored program entitled "ORDER.C", 150 which may be found in the Microfiche Appendix, page 26, lines 1 to 47 and page 27, lines 1 to 3. A stored program "PRLABEL.C" 160 and found within the Microfiche Appendix at page 17, lines 1 to 54 and page IS, lines 1 to 39, vas utilized to assign values of 0, 1, or 2 to the reģions available for printing on the labei, vhile leaving the reģions vith a value of 3 unchanged. Gray Ievels for each of the hexagons in a 3 celi by 3 celi cluster are assigned in conjunc-tion vith the stored program entitled "CELL CODE.C" 170 found in the Microfiche Appendix, page 23, lines 1 to 53; page 24, lines 1 to 53; and page 25, lines 1 to 43. A preference for storing the high priority message in an area proximate the acguisition target vhere it vlll be less susceptible to labei degradation is built into this auxiliary order program. Program "LA3EL.C" 180 is therefore employed to generate a bit stream suitable for input to the laser printer. Prooram "LABEL.C" 180 may be found in the Microfiche Appendix, page 28, lines 1 to 53; page 29, lines 1-52; and page 30, lines 1-36.

It can be seen that the use of black, gray and vhite permits a simple labei printing procedūra, because only black ink is necessary, vhen a Standard half-toning algorithm is used, in a 44 manner which is veli knovn ln the art. If other color combina-tlons ara used (vhich is feasible), the necessity for pnnting in other colors obviously creates subetantlal complexities when com-pared with the three-color black-gray-white approach or with a tvo-color black-vhite approach.

Thus, when each pixel of the printer has been assigned a black or white value, the labels may be printed to create an encoded format, as illustrated in Fig. 3, in vhich some hexagons are white some are gray and some are black, and in vhich an ac-quisition target region, preferably of black and vhite concentnc rings is formed at the geometric center of the label.

LABEL INTERPRETATION OR DECODING

Having described hov data is encoded in the label and printed, it is necessary to describe the subsequent label inter-pretation or decoding process. It vill be appreciated that it is desirable to perform the label interpretation function at very high speeds, on the order of a fraction of a second, in order to increase the efficiency at vhich the package manipulation (or other manipulation or label reading) process takes place.

There are tvo basie approaches that can be taken for capturing the image in the label reading process. The label can be read at relatively slov speeds, using a hand-held stātie fixed-focus seanner. Alternatively, an electro-optical sensor, having a servo-controlled focusing mechanism to permit dynamic scannlng of rapidly moving packages of variable sizes and heights is highly desirable to aehieve high speed operation. The decoding process and equipment. descrlbed belov vas demonstrated in connection vith a fixed-focus seanner. The process having the general capabili-ties deseribed herein vith respect to a stātie fixed-focus seanner is adaptable to a dynamic seanning system vith certain modifica-tions to the optical system as noted belov. When manipulating packages at high speeds, it is desirable to have a high speed scannlng mechanism vhich can read labels travelllng at a linear speed of about 100 inehes per second or more and pasaing belov a 45- LV 10820 fixed scanner location. The image procesaing function thue com-priaes the folloving steps. Fig. 7 provides an outline of the steps of the decodlng process. 1. I1luminatlon of the label

When a package, pārcel or letter ls traveling on a high-speed conveyor, the area to be illuminated is guite large, be-cause the sizes of the packages to be accommodated cn the con-veyor could be quite large and varlable. For example, a 42 inch wlde conveyor and packages of only several lnches ir. width up to three feet ln vidth (and similar helghts) are not ur.conunon ln package handllng systems. Therefore, the one square inch label may be located anyvhere acrosa the vidth of the conveyor. Packages are also likely to be located at skeved angles vith respect to the axis of movement of the conveyor belt. The pārcels, packages, letters or the like vill have different heights, so that the labels to be scanned may be located, for example, or.e inch or less above the conveyor, on the one hand, or up to 36 inches or more above the conveyor, on the other hand, vith respect to the maximum height packages that the described system can accommodate.

In order to properly illuminate the labels in accord-ance vith this invention, especially considering the vide range of package vidths, heights and the angle of presentation of the labels, it is desirable to use a high-intensity light sourca, vhich vill reflect veli based on the tvo or more optical proper-ties selected for the label. The light might be infrared, ultra-violet or visible light, and the light spectrum of uaable visible light may vary. The technique for sensing the light preferably involves sensing light reflected from the black, vhite and gray hexagons of the.label.

The illumination source must producē enough reflected light at the light sensor (for example a CCD device, as described belov) to permit the light sensor to reliably distir.guish among black, gray and vhite or vhatever optical properties of the hexa-gons are being sensed. In a dynamic scanning system an array of -46 LED's could be uaed to producē an illumination Ievel of about 10 mW/cm1 in the label illumination area at the Ievel of the label. The LED'e may be in an area array( vithout using a focusing lēns, or a linear array, vith a cylindrical focusing ler.s. A laser light source, passed through a euitable optical system to provide a line source of illumination could also be used in the practice of this lnvention.

The selection of the light source and the properties of the light source for the application in guestion are within the purviev of the skilled artisan. It is to be recalled that, since the label to be located is only one square inch in maximum di-mension, located at heights of up to 36 inches on a 42 inch vide belt travelling at speeds up to, for example, 100 linear inches per second, it is very important to be able to illununate the labels properly in order to identify and locate the labels quite promptly.

In the case of the stātie fixed-focus sensor utilized in the illustrative example, an illumination Ievel of about 2 millivatts/cm^ proved suitabie for the practice of the invention. This was accomplished by means of a fluorescent light source. 2. Optical Sensino of the Reflected Label Imace

The second step in the recognition portion of the de-coding process is to optically sense the illuminated area vith an electronically operated sensor. The camera/light sensor used in the illustrative example for a stātie fixed-focus seanning system comprised an industrial quality color CCD television camera, such as modei number WV-CD 130, available from Panasonic Industrial Company, One Panasonic Way, Secaucus, Nev Jersey 07094, fitted vith a 50 mm fl.3 C-mount TV lēns ineluding a 5 mm extension tube, available from D.O. Industries, Inc. (Japan), 317 East Chestnut Street, East Rochester, Nev York 14445 and identified under the brand name NAVITR0N™. The camera vas coupled to an image capture board designated modei number DT-2803-60, available from Data Translation Inc., 100 Locke Drive, Marlboro, Massachu-setts 01752. -47- LV 10820

Optical sensing may involve imaging the entlre label, utilizing an area sensor such as the above-described camera and image capture board or, in the alternative, may be accompllshed with a linear array sensor incorporating a charge coupled device ("CCD") chip, vherein the second dimenslon of the label scanning is performed by the movement of the package (and label). A suit-able CCD chip for thls purpose ls the Thomson-CSF ΤΗΧ 31510 CDZ, 4096 element high speed linear CCD image sensor, avallabie from Thomson-CSF, Division Tubes Electroniques, 38 rue Vautheir B.P. 305 92102 Boulogne-Billancourt Cedex, France. •For dynamic systems involving the movement of label-bearing packages on a conveyor system, it is desirable to have a long optical path betveen the labels being sensed and the light sensor. The primary reason for creating a long optical path is to reduee the change in apparent size or magnification of the label as sensed by a remote light sensor. For example, if the optical path is, say, four feet, the image size for labels one inch above the conveyor will be very different from that for labels three feet above the conveyor. īf a long optical path is used of, say, twenty feet, the image sizes of the same labels are almost the same. This allovs the area being sensed, regardless of height, to fill ali or substantially ali of the area of the light sensor, to achieve consistently high image resolution. If an area sensor rather than a line sensor is used, the same prin-ciple vould also apply. This may be accompllshed by means of a long optical path a's depicted in Fig. 6.

In order to be able to focus on labels of different height packages, a height sensor ls needed. An ultrasonic sensor may be used or a set of light beams may be broker by the package as a sensor. Either of these systems ls usable and may then activate a suitable adjustable focusing mechanism vith an open or closed loop mechanism to sense and adjust the position of the optical sensing elements {e.o.. lenses and sensor) in relation to each other on a contlnuous basie, as seen in Fig. 6.

Fig. 6 is a schematic vlev of a camera focusing and adjusting system operable in accordance vith the invention for -48- adjusting the position of the camera light sensor in accordance vith the helght of the package belng sensed. Fig. 6 demonstrates a view of a suitable lēna 196, coll drīve, helght sensor and feedback loop in accordance vith the invention. In Fig. 6, the helght sensor 206 may be an ultrasonic helght sensor or a light beam vhich is broken by each package travelling on the conveyor, for example. The height sensor output is fed to microprocessor 204 vhich in turn actuates coil driver 202 to move coil 200 on vhich CCD 198 or other suitable light sensor is mounted. A shaft position sensor 208 senses the position of coil 200 and its output to microprocessor 204 completes a feedback loop for sensing and adjusting the position of coil 200.

The sensor must be able to sense the reflected light coming from the illuminated labai, and must also producē an analog signal corresponding to the intensity of the reflectlve propertles of the label as recorded by the individual pixels of the electro-optical sensor. A suitable light source, as described above, may be mounted to a mounting surface above a conveyor to bathe an area extending across the entire vidth of the conveyor vith a light of predetermined quality and intensity. The reflected light from the label may be folded by a series of reflectors and then is sensed by an electro-optical sensor.

The purpose of the folded optical path is to create a compact and therefore more rigid system.

The analog video signal output of the sensor is then filtered. The analog electrical signal is utilized in conjunction vith an analog bandpass filter to detect the presence of an ac-guisition target on the data array. The analog signal is then converted to a digital signal using a conventional analog-to-digital converter incorporated in the image capture board de-scribed belov or by other means knovn in the art. In place of an analog bandpass filter, it is possible to substitute digital filtering circuitry to determine the presence of the acquisition target by comparing the digital data representative thereof to -49- LV 10820 the digitized signal output of the analog-to-digital converter, as more fully described belov.

An example of an area sensor having a CCD chip with a plurallty of detectors and whlch waa used in accordance with the invention is the previously described Panasonic WV-CD 130 color CCD television camera. The analog signal output of the sensor was communicated to the previously described Data Translation DT 2803-60 image capture board, including a 6 bit monochrome video A/D conversion for digitization and later operations. By means of a suitable stored subroutine the sequenced digītal output of the image capture board vas saved in a memory device as an exact replica of the image recorded by the optical sensor. 3. Processing the Reflected Image

The most important part of the invention is to process the optieally sensed image in order to be able to recreate and orient vith accuracy the original labai conflguration and the color (optical properties) of each hexagon. This is done by using the folloving steps, after which the known pattern by vhich the label vas origlnally encoded and bit-mapped may be used to decode the Information contained in the label. (a) Locatlng the Target Center.

Prior to utilizing the above-described CCD television camera and image capture board, as outlined in Fig. 10, an initialization program "DTINIT.C" 250 vas run to put the image capture board into a knovn ready State and to load the output color look-up tables, folloved by the program "DTLIVE.C" 255 to put the image capture board in "live mode." The program "DTGRAB.C" then causes the image capture board to digitize the scene into a 240 rov by 256 column image memory, vith samples stored as 6 bit values right Justified in bytes. The foregoing programs may be found vithin the Microfiche Appendix respectively at page 31, lines 1 to 53; page 32, Lines 1 to 39; page 33, lines 1 to 22; and page 34, lines 1 to 19. Tvo auxiliary programs 50- "DTSAVE.C" and "DTLOAD.C" allov ecreen images to be transferred to and from a atoraga medium. Source code llstinga for the fore-going programs may be found vithin the Microfiche Appendix, re-epectively, at page 35, lines 12 to 33; and page 36, lines 13 to 5 33.

In first acguiring the label image, a conventional analog band pase filter can be used to identify two or more op-tical propertles of the acquisition target Concentric Rings.

These tv© optical properties are preferably the colora black and 10 white because the greatest contrast will create the strongest eignal energy. In order to find a fixed pattern of transition from black to vhite to black, etc., it is desirable that a linear scan across the accfuisition target and passing through the center of the target yield a uniform frequency response regardless of 15 label orientation. Thus, the target rings are optimally com-priaed of contraating Concentric Rings. The sensor output vas then bifurcated and taken through tvo detection paths. One path detects ali of the energy in the output and the other measures the energy at the ring frequency. When the tvo outputs are com-20 pared, the energy in the ring detector most closely approximates the energy in the ali energy detector vhen a scan through the acquisition target center is being sensed. The acquisition target center is located vhen this closest approximation occurs. Source code listings relating to the creation of a digital band· 25 pass filter and filtering process may be found in the Microfiche Appendix under the File Name "FIND.C," pagea 39 through 43. Hov-ever, in the dynamic preferred embodiment of the invention, the firat filtering atep vould preferably use an analog bandpass filter or else a sampled analog bandpass filter, although a 30 1 digital filter is usable.

It is to be noted that the acquisition target locating atep denoted "FIND.C" 280 in Fig. 10 ia indicated as optional in Fig. 7, because a hand-held scanner can be used in the process of the invention, in vhich event the operator could properly place 35 the scanner to assure correct alignment of the aenaor. This is, •51- LV 10820 of course, much slover than the use of an automated sensor and the use of the automated sensor is preferred in a high speed operation. īf an automated sensor (not hand held) is used, locating the target is a reguired step of the process. S As an alternative to an analog filter described above, a digital bandpass filter may be constructed using the Parks-McClellan algorithm supplied with the software package "Digital Filter Designs Softvare for the IBM PC" (Taylor and Stouraitis, Marcel Dekker, Inc., New York, Ν.Υ., 1987). 10 λ one-dimensional digital band paas filter has been utilized in connection vith the present invention to filter a normalized digital bit stream, as described belov, through the folloving filtration sub-routines. The band being filtered is the expected ring frequeney. The one-dimensional digital, band-1S pass filter vas designed for a sampling rāte of 400 pixels per inch and a length of 12S pixels (or 0.3125 inches), and designed to be based upon the size of the printed acguisition target rings, as illustrated in Fig. 3. The frequency vas 300/16 line pairs per inch, yielding a normalized frequency, (vhere 400 line 20 pairs per inch * 1) of 300/16 x 400 or 0.046875. A filter vith a passband extending 5% belov this frequency and 15% above vas chosen because label distortions typieally result in image shrinkage and therefore an increased frequency. Stop bands from 15% belov the frequency dovn to 0 and from 25% above the ring 25 frequency to 0.5 (Nyqulat limit) vere constructed. The filter coefficients vere stored in the file "IMPULSE.LUT" 275, per Fig. 10, for later operations, deleting the first 62 coefficients, because the filter is symmetrical. A flov chart is illustrated in Fig. 8. Further reference may be made to the source code 30 listings in the Microfiche Appendix, under the file name "FIND.C", 280 starting at page 39. A filter of 25 pixels in length vas constructed by sampling the band pass filter at output intervāls corresponding to the measured horizontal magnification. For example, if the 35 horizontal magnification of the image is 80 pixels per inch, every -52- fifth aample of the fllter would be uaed (400/60 * 5 pixela).

For non-integer steps, linear interpolation oi adjacent filter samples la used. A second 25 by 25 pixel two-dimensional filter waa also utilized. Sample values for thia two-dimensional filter were based on the Euclidean distance of each point from the center of the filter, vhich were scaled for appropriate horizontal and vertical magnificationa. Linear interpolation ia then uaed for non-integer sampling intervālā.

The output of the above-mentioned one-dimensional filter was squared and smoothed with a first order recursive lovpass filter, providing an exponential vindov of past history. When the amoothing filter output exceeded a predetermined threshold, an optional two-dimenaional· filtering atep was employed to verify the existence of the target and to accurately determine its loca-tion, aa deacribed belov. The first part of the tvo-dimenaional filtering uaed a reduced filter aize of 10 pixela by 10 pixela to aave computation. Thia filter scana a rectangular area around the location detected by the one dimensional filter. If the maxi-mum two-dimensional correlation exceeds a predetermined threshold, then the final stage of tvo dimensional filtering, vith the full 25 pixel by 25 pixel filter, vas applied to a small square window around the maximum, If the best reault of thia filter exceeded & predetermined threshold, the center vas detected. If any of the thresholds were not exceeded, the program partially Ndischarged'' the amoothing filter and reverted to one dimenaional acanning.

If one dimensional acanning completed vithout detecting the pres-ence of the acgulsition target, the program exited vith an error return. For any fujrther elaboration of the filtering process em-ployed in the illustratlve example, reference ahould be made to the aource code listings in the Microfiche Appendix, pages 39 through 42. -53- LV 10820 (b) Normalization of Sensed Image

Reflected light intensities recorded by the optical sensor employed may vary due to variatlons ln illumir.ation, print density, paper refledtivity, camera sensitivity aod other reasons involving degradation to the label, for example, foldmg, varping, etc. As an optional (but desirable) step, the reflected light sensed by the sensor and communicated to the memory may be nor-malized by conventional procedures. Using techniques kr.ovn in the art, a stored normalization program "NORM.C" 270, depicted on Fig. 10, was used to analyze the intensity Ievels of reflected light from the label, as recorded by blocks of pixels in the scanner, to find the minimum and maximum reflected light intensi-ties recorded for the data array. The seguenced digital output of the above-described scanner and image capture board combina-tion vas loaded from memory to the Computer to be further operated upon by said stored normalization program.

Utilizing an ecfuation y * mx ♦ b, vhere the minimum in-tensity substituted for x vill yield a v^lue of y * C ar.d a max-imum intensity substituted for x will yield a value cf y = 63, the recorded intensities of reflected light for each pixel vere adjusted so that the blackest black and the vhitest vhite present in the stored image vere established as the Standard, ar.d the other shades of black, vhite and gray vere adjusted to those standards. The normalization step thus makes the ser.sed image easier to process. Normalization vas carried out using the stored program "NORM.C1’ found ln the Microfiche Apper.dix at page 37, lines 10 to 52 and page 38, lines 1 to 11. It vīli be appreciated that other, mora sophisticated normalization proce-dures knovn in the art may be applled. (c) Rescallna the Image

For subsequent computations, the stored replicated label image is rescaled to create an image vith equal horlzontal and -S4 vertical magnification. Again, thie is an optional step, but it facilitates the fast and accurate recovery of the encoded Information. The rescaling operation was performed to gļve the image a uniform horizontal and vertical sampling resolution of, for ex-ample, 150 pixels per inch, as used in the illustrative stātie fixed focus embodiment of the invention.

The rescaling operation occurs by computing the frac-tional row and column addresses of sajnples at 1/150 inch, based upon the knovn horizontal and vertical magnification. Each point on the nev uniform rescaled image is then extracted from an ap-propriate set of points on the image replicated in the storage medium. Bilinear interpolation isused to approximate the value of points at fractional addresses. The rescaling places the center of the label at a knovn position in memory. The rescaled image is stored for later use in the searehing step. Ali subse-quent process steps then assume that a rescaled label image is centered on a knovn position on the grid, but it should be noted that this does not indicate the orientation of the label, which may stili be skeved vith resoect to the sensor. The rescaling operation is carned out under the control of a stored subroutine found in the source code listings vithin the Microfiche Appendix at page 42, lines 14 to 52 and page 43, lines 1 to 14. (d) Tvo-Dimensionaļ_Clock Recoverv

The next seguence of steps of the process are referred to collectively as "tvo-dimensional clock recovery." The steps are performed by a suitable stored program and subroutines en-titled "CLOCK.C" 290, depieted on Fig. 10, and found within the Microfiche Appendix at pages 44 through 51. This operation is performed in two dimensions on the rescaled image to determine precisely the position of each hexagon on the original data array. The purpose of clock recovery is to determine the sampling loca-tions and to correct for the effects of varping, curling or tilting of the label, since the label may not be perfectly flat. This is an important part of the process and its application is -55 LV 10820 not limited to hexagonal encoded labele. It may be applied to other processes for decoding an encoded label comprising a regu-lar, two-dimensional grid, such as scjuares, triangles, etc.

One-dimensional clock recovery ls a general concept which is well understood in the signal Processing field. Two dimensional clock recovery is an extension of that process and will be understood, upon reflection, by the skilled technician.

It wi11 be understood that the "clock recovery" term is somevhat confusing to the non-expert, since it does not relate to timing. (i) Edoe Enhancement and Non-Llnear Operation

The first step in accomplishing clock recovery may be performed by various non-linear mapping operations knovn in the art to create signal components at a specified clock frequency that are missing from the digitlzed image output from the optical sensor and image eapture board. The purpose of non-linear mapping is to taka the (preferably) normalized and rescaled image which exists at this point in the process and to form it lnto a two-dimensional non-linear map vhich enhances the transitions be-tween adjacent contrasting hexagons. In the preferred embodiment of the present invention, this is done by Standard deviation mapping. This step can also be performed by filtering vith an image differencing kernel, several means for vhich are knovn in the art, such as La?lace or Sobel kernels, and then an absolute value is determined or sguaring of the results is performed. These procedūras may be found in the text Digital Image Processing, Rafael C. Gonzalez and Paul Wintz, Addison Wesley, 1977.

In Standard deviation mapping, the image vith undif-ferentiated cell-to-cell edges is sto:ed in memory. A Standard deviation map is then created to locate the edges of adjacent contrasting hexagons by determining the Standard deviations of 3x3 groups of pixels (this is different from the 3 celi x 3 celi clusters), to determine the Standard deviations of the pixel intensities. The Standard deviation computations are performed to determine the reģions of pixels having a fixed color (the -56- lovest Standard deviations), representing the interior of a hexa-gon or the interface betveen two like-colored hexagons, as op-posed to the groups of pixels havlng higher Standard deviations, vhich represent transitions from a hexagon of one color to an adjacent hexagon of a contrastir.g color. Because adjacent hexa-gons frequently have the same color, the Standard deviation map will not completely outline every hexagon. Missing borders or edges betveen hexagons will result from the fact that the Standard deviation mapping process cannot distinguish interfaces betveen hexagons of the same color. Further aspects of the clock recovery process are intended to regenerate these missing transitions .

The decoding process of the instant invention may be utilized for any of the previously described label embodiments, as illustrated in the accompanying figurēs. Encoding units of various geometries may easily be accommodated and such optically encoded polygonal celis may be arrayed vith the geometric centers of adjacent polygonal celis lying at the vertices of a knovn, predetermined tvo-dimensional array.

When the optically readable labels of the instant invention are "read" vith optical sensors of the types described herein, the particular gecmetry or shape of the individual encoding units or polygonal celis ls not determined by the optical sensor. Instead, the sensor simply samples the optically readable label at a knovn number of samples per inch and records the intensity of the reflected light corresponding to the optical property of the particular sample area that has been imaged.

These values are then stored in a storage medium for later Processing. In other vords, the electro-optical sensor records the average light intensity sample area-by-sample area across the entire label surface, regardless of vhether or not anything is printed on the label. This is vhat is meant by storing the image vith undifferentiated cell-to-cell edges in memory. For this reason the decoding process is readily adaptable to reading optically readable labels of videly varying configurations, so -57- LV 10820 long as the centera of the polygonal encoding units Īle at a predetermined spacing and dlrectlon on a tvo-dimensional array.

In practice it has been found that alterations of the hexagonal encoding cell-based 3ystem, as in the case of label embodiments employing polygons substantiaily in the shape of hexa-gons as illustrated in Fig. 15, result in negligibie reduction of the eystem's performance. Utilizing polygonal ehapes vith poorer packing characteristics, or arrays of partially contiguous or noncontiguous polygons rather than contiguous packing, will then result in a poorer, but nevertheless, usable system performance for many applications. At some point, hovever, due to the opti-cally unresolvable high frequency components of lover order poly-gonal encoding celis, inefficient celi packing and predetermined tvo-dimensional arrays resulting in large interstitial spaces betveen polygona, the system performance will fail to an unaccept-ably low Information etorage and retrieval capacity.

The aeceptability of the systein depends on the quality of the signai recovered by the electro-optical sensor. By alter-ing the sensing system, as for exampie by increasing the number -58- of samples per unit area across the label surface, one could im-prove the aignal recorded by the sensor and improve the Information storage and retrieval characteristics of such partially contiguous and noncontiguous label configurations.

Such adjustme.nts, in order to make such less desirable label configurations usable, would be vithin the abilities of one of ordinary skill in the art of electro-optics.

The process, therefore, allows a wide variability in terms of the label article, cptical signal acquisiticn means and signal processing. Polygonal celis, of either reguiar or lrreg-ular form may be used as encoding units on the optically readable labels of the invention. Further, so long as the spacing and direction of the centers of the polygons are knovn ir. relation to adjacent polygonal celis, the polygonal encoding celis may lie on a predetermined array, other than a hexagonal array, and the poly-gons may be arranged contiguously, partially contigucusly or even noncontiguously on the optically readable label.

As explained in greater detail below, the nonlinear mapping techr.igues, specifically the Standard deviation mapping technigues disclosed here'in in relation to the preferred embodi-ment, facilitate reconstruction of the missing transitions or edges betveen polygonaI celis of like optical properties. More-over, the sane feature may overcome the lack of transitions betveen polygons and interstitial spaces betveen polygons of like optical properties. This is the situation vhen label configura-tions contaimng partially cor.tiguous or noncontiguous polygons are utilized. This feature is accomplished through the folloving Fast Fourier Transformation, filtering and inverse Fast Fourier Transformation steps.

An optional technique utilized in the preferred embod-iment of the present invention reduces the computations needed to generate the Standard deviation map. Normally, to conpute the sum of the nine pixels in each 3x3 pixel block, eight addition operations vould be needed. Thie may be cut in half by replacing each pixel of the image vith the sum of itself and the pixels -59 LV 10820 immediately to ite left and right. Thie raquiras two additiona per pixel. Then, the same operation ie performed on the new image, except the sum is computed for pixels immediately above and b«low. This requires two more additiona for a total of four.

It can be shovn that, at the end of these steps, each pixel has been replaced by the sum of itself and its eight immediate neighbors.

Standard deviation mapping ia the deaired technique for creating this map of hexagons corresponding to the original data array but vith missing transitions betveen original hexagons of the aame color. The specific Standard deviation mapping tech-niques utilized in conjunction vith the illustrative embodiment may be found vithin the source oode listings in the Microfiche Appendix at paga 45, lines 14 to 53 and page 46, llnes 1 to 4. (ii) Windowlnq

The next subroutine, called vindoving, is optional. Hindoving vas used in the practice of the invention to reduce the iotensity of borders vhich are not associated vith hexagon outlines These borders occur at tvo locations: the target rings and the uncontrolled image surrounding the label. A veighting function is utilized to reduce the intensity of these areas. The details of hov to use vindoving as a precursor to a Fast Fourier Transform is vithin the purviev of the skilled artisan. The vindoving procedūra utilized may be found vithin the source code listings con-tained in the Microfiche Appendix at page 46, lines 6 to 22. (iii) TvanDlmensional Fast Fourier Transformation A tvo-dimensional Fast Fourier Transformation of the digital v.alues corresponding to the (optionally) vindoved Standard deviation map is then performed under the control of a commercially-available stored program. In operation, a Computer performs a Fast Fourier Transform of the image generated by the prior step to yield a tvo-dimensional representation of the spac-ing, direction and intensity of the interfaces of contrasting -60- hexagons identified in the Standard devlatlon mapplng step.

Simp1y stated, the Fast Fourier Transform is a measure of the spacing, direction and intensity of the edges betveen hexagons, where known. Thus, the regular spacing and directionality of the hexagon boundaries wi11 cause certain points in the transform domain to have a high energy Ievel. The brightest point will be at 0,0 in the Transform planē corresponding to the DC component in the image. The six points surrounding the Central point repre-sent the spacing, direction and intensity of the edges betveen hexagona.

It vill be recognized by one skilled in the art that, as for hexagons, a tvo-dimensional representation of the spacing, direction and intensity of the interfaces of contrasting polygons identified in the preceding Standard deviation mapping step can also be computed by performing a Fast Fourier Transform of the digital data corresponding to the non-linearly mapped sensed label image. Thus, the spacing and directionality of the polygon bor-ders vill cause certain points in the transform domain to have high energy. The number of points of higher energy surrounding the center point at the 0,0 coordir.ate of the transform planē vill depend on the geometry of the particular polygonal encoding celi used to make the optically readable label. As for hexagons, hovever, such points surrounding the Central point vill represent the spacing, direction and intensity of the edges betveen polygor.s or the edges betveen polygons and interstitial spaces if the label configuration is either partially contiguous or noncontiguous in nature.

Since the image is real (not complex) valued, the Transform domain is point symmetric about the origin. Thus, only a half planē of the transform domain must be computed, thereby saving nearly a factor of tvo in computation time. Elimination of these computations also reduces the amount of effort required in the subsequent image filtering and Inverse Fast Fourier Trans-formation steps. The Fast Fourier Transform program utilized in connection vith the illustrative embodiment of a stātie fixed -61- LV 10820 focus system waa the commercially-availabie aubroutine R2DFFT from the 87 FFT-2 package from Microway, Inc. of Kingaton, Maaaachusetts. (iv) Filtermo the Imaae A filtering proceaa ia now requlrad to reconatruct the complete outline of ali of the hexagons in the image donain, utilizing the transformed digital data. Thia ia done by elimi-nating any tranaform domam points that do not correapcnd to the desired apacing and direction cf hexagon boundaries identified in the atandard deviation mapping atep. Six prominent pomta ih the tranaform domam arise because of the hexagonal honeyconb atruc-ture of the label. Only three points in the tranaform domain are actually identified, becauae the image ia point aymmetne about the orlgin, and the aecond three pointa may be inferred from the first three. Γη the preferred embodiment, filtering ia performed in three ateps to eliminate tranaitiona from the atandard deviation mapping atep, vhich are too far apart, too close tcgether. and/or in the wrong direction.

First, high pass filtering ia performed by zeroing ali points vithin a predetermined circle around the origin of the Tranaform domain, but at a distance extending outvard from the origin, short of the six prominent points arrayed in the shape o.' a hexagon, in the graphic tranaform domain. These pomta corres-pond to spacinga greater than the hexagon spacinga and thus carry information pertaining to the miaaing tranaitiona in the label image. To recreate miaaing tranaitiona in the label image, it ia necessary to eliminate the information about the miaaing transi-tions in the Fourier Transform domain.

Next, ali points outaide a certain radius-beyond the six prominent points in the Tranaform domain are zeroed. These correspond to spurious transitions that are spaced too close to-gether. Thia operation combines with the first one to form a ring of remaining pointa. Creating this ring ia equivalent to performing spatial bandpass filtering. The inner and outer radii -62- οf the annulus are determined by the expected spacing of the hexa-gon outllnes. Slnce the hexagon "diameter" is expected to be 5 pixels ln the example being described, and for a trar.sform length of 256 pixels, the hexagonal vertices in the Transform domain should be 256/5 = 51.2 pixels away from the center. Accordingly, a rlng with an inner radius of 45 pixels and an outer radius of 80 pixels corresponds to hexagon diameters of 3.2 to 5.69 pixels was used. A filter with a preference for passing higher freguen-cies waa used because label deformations, such as varping and tilting, cause image shrinkage.

After performlng the spatial bandpass filtering des-cribed above, an annulus with six prominent points exists, each point having equal angular spacing vith respect to the center (0,0 point) of the transform domain. To complete the task of re-jecting undesired information in the Transform domain, a direc-tional filtering step is employed. Any point at too great an angular distance from the prominent reģions in the Transform domain is zeroed. This has the effect, in the image domain, of removing any edges that do not occur in one of the three direc-tions dictated by the hexagonal hor.eycomb tiling pattern.

To perform directional filtering it is necessary to find the most prominent point remaining after spatial bandpass filtering. This point is assumed to be one of the six prominent points of the transform domain resembling the vertices of a hex-agon. Five othar prominent points at the same radius from the center and vith angular spacing of multiples of 60 degrees are also evident in the transform domain. Therefore, ali other points vith an angular distance of greater than 10 degrees from any of these points are eliminated. S.'a vedges of the ring re-main. By this directional filtering step, any information of incorrect spacing or direction in the image domain is eliminated. Elimination of this incorrectly spaced information enables the restoration of a complete outline of each hexagon in the image domain. -63 LV 10820

The foregoing filterlng stepe are performed under the control of stored subroutines contained in the source code list-ings within the Microfiche Appendix at page 46, lines 26 to 53; page 47, lines 1 to 52; page 48, lines 1 to 52; and page 49, lines 1 to 46.

The foregoing discussion of the filtration scheme em-ployed for the preferred label embodiment comprising contiguousiy-arranged hexagons requires modification when different predeter-mined two-dimensional arrays ara utilized for the optically readable label. It vill, nevertheless, be appreciated by one skilled in the art that only siight modifications to the filtration scheme are required to aecommodate the different label con-figurations that have been previously described herein, and vhich are illustrated in the- accompanying dravings.

Once the individual polygonal encoding celis are de-cided upon, it is predetermined that their respective boundaries vill have certain angular spacings, and a given number of sides of given length. Next, it is necessary to determine the rela-tionship of adjacent polygons, as for instance, vhether they vill be contiguous, partia-lly contiguous or noncontiguous. Also, the geometric array upon vhich the geometric centers of the polygons vill be arranged needs to be established. Since the foregoing label geometry is predetermined a person of ordinary skill in the art can construct the appropriate filtration scheme to filter the energy points in the transform domain, so that only the brightest points corresponding to the appropriate spacing and direction of polygons boundaries is operated upon by the inverse Fast Fourier Transform subroutine.

Concerning the uctual filters constructed, it vill be appreciated that it is necessary to construct' an appropriately dimensloned spatial bandpass filter based upon the predetermined spacing of the polygonal encoding celis. Then, it is desirable to construct a directional filter to filter out energy points -64 other than the most prominent polnts corresponding to the axes of the predetermined tvo-dimensional array of the polygonal encoding celis. This eliminates any Information concerning the incorrect spacing or direetion of the polygonal encoding celis in the image domain and the interstitial spaces īf present. By eliminating such incorrect Information a complete array of the centers of the polygonal encoding celis can be reconstructed in the image domain by means of inverse Fast Fourier Transformation in accordance with the process step descnbed below. (v) Inverse Fast Fourier Transformation

To ačtually return to the image domain, thereby restor-ing the outline image of the contiguous hexagons of the data array, it is desirable to perform a tvo-dimensional Inverse Fast Fourier Transform {2D-1FFT> on the filtered transform domain data. The inverse transform is implemented by a Standard tvo-dimensional Inverse Fourier Transform subroutine (R2DIFT) available in the 87FFT-2 package from Microvay, Inc. of Kingston, Massachusetts.

Upon completion of the inverse Transform step, the outline of every hexagon is restored in the image domain. In the nev image, the centers of the hexagons have high magnitude. The actual mag-nitude of the spots at the hexagon centers is dependent on hov many edges were in its neighborhood. More edges create greater energy at alloved freguencies and hence high magnitude spots.

Fever edges give rise to lover magnitude spots. The magnitude of the spots is a good measure of the confidence Ievel in the clock restoration at any given point. (e) Malor Axls Eetermlnatlon

The hexagonal image has nov been recreated but its orientation needs to be determined.

The hexagonal honeycomb pattern of the invention has three "axes" spaced 60 degrees apart. The direetion of these axes is established by the brightest points in the transform domain after spatial bandpass filtering. It ls now possible to ascertain vhich of these three axes is the major axis. This step -65- LV 10820 ls optional. If thia step is not performed, the label vould have to be decoded three times, using each of the three axes, with only one axis yielding a meaningful message. The major axis is arbitrarily chosen as the axia which runa parallel to two aides of the label as described hereinabove and depicted in Fig. 2.

If the boundaries of the square label are determined based on the kr.ovledge of the major axis, then most of the energy in the restored hexagonal outllne pattern will be ir.side this square's boundaries..

To determine the major axis, each of the three axes is assumed to be the major axis. The consequent square label out-line is determined for each trial axis, and the total clock restc-ration pattern energy interior to that square, is determined from the digital energy data output from the inversa transform subrou-tine. The correct trial is the one with the most er.ergy. The angle of this major axis is then stored for the initiaiizatior. step and other searching operations. At this juncture, it is not yet knovn vhether the recorded angle is in the correct direction or 180 degrees away from the correct direction. The source code listings in the appended Microfiche Appendix pertaimng to the determination of the major axis may be found at page 49, lines 48 to 54; page 50, lines 1 to 53; and page 51, lines 1 to 5. It will be appreciated that ali three label areas do not need to be> determined iu toto. since the energy in the areas conmon to ali three squares does not need to be determined. (f) Searching A stored program entitled "SEARCH.C" 300, depicted on pig. 10, combines the Transformed and regenerated hexagon center Information with the stored intensity Ievels of the original image so as to determine the gray Ievel value of each hexagon.

The search is performed in such a way as to minimizē the chances of "getting lost" vhile searching. The end result is to obtain a matrix of the gray Ievel value for each hexagon of the data array, The source code listings for "SEARCH.C" may be found vithin the -66-

Microfiche Appendix at page 52 through 60. Four important Information arraya are constructed during the first part of the SEARCH.C program. The array CVAL (clock value) stores a measure of the quality of the recovered clock signal for each hexagon, 5 while the array CVAL stores the grey ievel value (0-63) at the center of each hexagon. The remaining arrays IVAL and JVAL store the row and column locatior.s of the center or each hexagon. ( i ) Initialization Steps 10 From the major axis angle determined in step (e) and the knovn spacing of the hexagons (5 pixels) in the example, the expected horizontal and vertical displacements from the center of one hexagon to the centers of the surrounding six hexagons are computed. 15 Following these computations, the SEARCH.C program operates on the clock recovery signal, retrieved from memory and the rescaled label image, also retrieved from memory. The funda-mental purpose of the initialization subroutine found in the Microfiche Appe.ndix at page 52, lir.es 13 to 54; page 53, lines 1 20 to 43; page 56, lines 47 to 57; and page 57 lines 1 to 35 is to merge and condense the information from these two sources and to generate a data matrix providing the grey scale value for each hexagon.

The initialization step of the search is bounded by a 25 square around the label's center of about 1/3 of an inch on a side. VVithin this area, a good starting point is the point of highest magnitude in the recovered clock signal array is found. Then, the location of this starting point relative to the center of the label is determined. This starting point is a point where 30 the clock signal is strong and distinct, and also a point rela-tively near the center of the label. A strong, distinct signal is desired to ensure that searching begins with a valid hexagon center, and it is desired that the point be near the center of the label so that its absolute location can be determirjed vithout 35 serious influence from varping or tilting. The measure of the 67 LV 10820 quality of a point ln the clock recovery pattern ls the point'e magnitude minus the magnitude of its eight surrounding points.

The rectangular coordinates of the atarting point are converted to polar form, the polar coordinates are adjusted relative to the previousiy determined major axis angle, and this result is converted back to rectangular form. Theae coordinates are scaled according to the expected rov spacing (4.5 pixels) and column apacing (5 pixels) to arrive at the insertion position on the hexagon matrix. The clock quality, grey Ievels and locations corresponding to the atarting hexagon are then inserted in the respective arrays CVAL, CVAL, IVAL and JVAL. (ii) Main Search Loop

The main search loop proceeds to locate the centers of the remaining hexagons. The loop terminates when the expected number of hexagons has been located. The order of the search for hexagon centers is extremely important. The increased reliability of the decoding process ln the face of label degradations comes from the particular search technigue employed, as described belov.

Each iteration of the search loop begins by recalling the location of the highest magnitude clock recovery spot whose neighbors have not been searched for their strongest values.

From this knovn point, the search vill be extended one hexagon ih each of six directions. The effect is to build up the search pattern along a path from better to vorse recovered clock qual-ity. Thus, if there is a veak area of recovered clock, e.o. at the label center or an obliterated area, the search algorithm skirts around it rather than going through it. By outflanking these veak areas and saving them for last, the probability of getting lost on the grid is greatly reduced. Since getting lost is Just as bad as reading a gray Ievel incorrectly, this charac-teristic of the search algorithm is extremely poverful. A subroutine found in the Microfiche Appendix at page 53, lines 50 to 54; page 54, lines 1 to 53; and page 55, llnes 1 to 55, is responsible for searching the neighbors of the best quality clock value found in the main loop. The subroutine loops six times, once for each hexagonal neighbor of the hexagon then under consideration. First, the posltion of a neighbor is com-puted. If this neighbor is outside the label boundary, the loop iteration terminates.. If'not, the neighbor is checked to see if it has already been searched from another direction. The loop iteration vīli terminate if the neighbor has been searched, since the algorithm makes earlier searches more reliable than later ones. If the neighbor gets beyond this tēst, the expected po-sition of the neighbor1s center in the clock recovery pattern is computed, At this point, a gradient search for the highest magni-tude clock signal is performed. The eight pixels surrounding the recovered position are searched to see if a higher clock value is found. If it is, then the best neighboring point has its eight neighbors checked to see if an even better value is found. This gradient search provides a degree of adaptation which is impera-tive if varped and tilted labels are to be read. The subroutine then goes on to the next neighbor or retums when ali neighbors have been checked.

As mentioned above under step (d), as a result of the data transformation processes, the reconstructed grid now carries information regarding the geometrlc centers of the polygonal encoding celis. This grid has more energy in areas vhere more contrasting interfaces origmally existed. The centers vill lie on the predetermined tvo-dimensional array having a predetermined number of equally- or unequally-spaced axes, as the case may be. The information concerning the spatial relationship of the axes of the predetermined tvo-dimensional array may desirably be used in the major axis orientation step.

It vill be appreciated, hovever, that the algorithm could be appropriately modified to have the decoding process determine the actual geometry of the tvo-dimensional array and from that determination proceed to determine the filtration scheme, the eo-called major axij of the label (i.e the axis of the tvo-dimensional array that is parallel to tvo sides of a 69- LV 10820 square optically readable label as discussed heraln) and provide the necesaary coordinates for the searchlng subroutine.

Khether the geometry of the label is determir.ed by such an optional atep as described above or simply entered into the decoding process through appropriate modificatlons to the tvo-dimensional clock recovery process, the variety of label con-figurations disclosed and discussed herein can be easily accommo-dated by one of ordinary skill in the art. It will be appreciated that the number of axes upon which the centers of the individual, adjacent poiygonal encoding celis are arrayed and their respective angular orientatlon, can be substituted in the major ax:s deter-mination step for the three axes of the hexagonal array of the preferred embodiment. Therefore the maJor-axis of the predeter-mined tvo-dimensional array can be determined vithout performing the trial and error analysis described above in step (e).

As for the hexagonal array of the preferred embodiment, the information from the major axis determination step and the knovn spacing of polygons may be used to compute the expected horizontal and vertical displacements from the center of one polygon to the centers of surrounding polygons. Folloving these computations and after making the necessary adjustments to the search subroutine, the searoh, including the initialization step and main search loop step can proceed for the particular label configuration that is being employed. It vill be appreciated that such minor adjustments to the search routine SEARCH.C 30C in the appended source code listings are vithin the abilities of a person of ordinary skill in the art.

After the subroutine completes, the current center lo-cation is marked so that it is not searched agaln. The effect is to delete this position as a candidate for having its neighbors searched. For each loop iteration, from 0 to 6 nev candidates are added and one candidate is deleted. An efficient lmplemen-tation could use a data structure which keeps candidates in magni* tude order as insert and delete operations are performed. One such structure is called a priority queue (Reference! The Peeigņ -70 and Analvsls of Computer Algorithms, Aho, Hopcroft and Ullman, (Addison Wesley, 1974)). It is known that a linear search algo* rithm requlra3 order n‘ operations vhereas an efficiently imple-mented priority queue uslng a balanced tree or heap structure reguires order n log n operations. An order n search algorithm based on bucket sorting could also be used, if recovered clock values are scaled and reduced to a small range of integers. (g) Histogram Ceneration and Thresholding

After the main search loop terminates, the locations of the centers of ali hexagons have been determined and the gray values of the centers of ali hexagons, which have been stored, are completely filled in. The next step is to threshold the dig-itized grey Ievel values in the range 0 * 63 to the discrete Ievels of, for example„ black, grey, and white (for a black, white and grey label). This is done by building a histogram of the label image intensity values from the hexagon centers. Slicing Ievels ean be determined by looking for dips in the histogram.

The specific subroutine utilized to construet the histogram and determine the slicing Ievels may be found in the appe.nded source code listings in the Microfiche Appendix at page 5S, lines 16 to S2 and page 56, lines 1 to 15. (h) Coarse Grid Correction and Flnal Orlentatlon

After thresholding to discrete Ievels, tvo distortions may stili be present. First, the array may be off ce.nter. This can happen if the initial search step does not correctly determine the location of the beet quality clock signal relative to the label center. The second possibility is that the entire label has effectively been read upside down since the major axis angle has an ambiguity of 130 degrees. λ stored subroutine found at page 5Θ, lines 1 to 54 and page 59, lines 1 to 24 vithin the Microfiche Appendix performs the function of determining vhether the label is off center. If the label has been positioned correctly, the coordinates of the -71 LV 10820 center row should pase through the center of the labai. To determinē if a vertical positioning error has been made, rows above the hypothesized center row are checked to see which would form a line passing closest to the label center. If a row above or below 5 is closer than the hypothesized center rov, then the appropriate shift up or dovn is made. If the left justification of short rows has been performed incorrectly, this is adjusted by shifting short rows one position to the right.

Horizontal positioning errors and upside dovn reading 10 are checked using Information embedded in the label knovn as coarse grid information. The Information is distributed in 3 celi x 3 celi clusters of hexagons as described hereinabove. Since the label may be, for example, on a 33 rov by 30 column grid, these clusters form a 11 by 10 grid. The bottom center 15 hexagon of each complete 3 celi x 3 celi cluster has a special property vhich is provided during encoding. There is a guaran-teed transition on either side of this hexagon, as previously described in connect-ion vith Fig. 4. For example, if the bottom center hexagon is black, the bottom left and bottom right hexa-20 gons must be either gray or vhite. A stored subroutine found at page 59, lines 27 to 52 and page 60, lines 1 to 33 of the Micro-fiche Appendix takes advantage of this transition property to remove the final tvopossible distortions. First an array is created vhere each element of the array indicates vhether a 25 transition took plača betveen tvo horizontally adjacent hexagons. Then the array is checked for each of 9 hypothetical slides of the coarse grid arranged as a 3 x 3 pattern around the expected slide of 0. One of these slides vill shov a better match betveen actual and expeoted transitions, and this slide position is re-30 tained. Next, the same hypothesis is checked under the assump-tion that the label vas read upside dovn. This vill happen if the major axis angle actually pointed right to left in relation to hov the label vas printed rather than left to right.

If the label vas simply inverted, 1. e., interchanged 35 higher rovs vith lover rovs and higher columns vith lover col-umns, then the results of slidings should be inverted as veli. 72

Hovever, one lmportant transformation must be performed to cor-rectly lnvert the label. During reading the short (ler.gth 29) rows ars left justified; thus, when the Label is inverted these labels must be right Justified. The adjustment is made, and it is this procedūra vhi-ch will raake the results of the slīde hypo-theses other than a simple inversion. In fact, the best result from the slide tests will be better than any previous tēst īf the label was actually read upside down.

Having determined vhether or not the label was read upside dovn, and vhether there was any slide in the absolūts positioning, the label matrix can nov be decoded. ' With correct determination of the image and slide, the image Processing func-tions are complete and the data decoding processes are started. 4. Decoding A stored program "RD.LABEL.C" 182 on Fig. 9 found vithin vithin the Microfiche Appendix at page 61, lines 1 to 52, and page 62, lines 1 to 28 reads the file generated by the search program and generates a bit stream file vlth, in the preferred embodiment, 1292 bits. It uses a stored subroutine Celi Dec.C 183 on Fig. 9 and contained in the Microfiche Appendix at pages 63 through 66 to mask out unusable hexagons, and to apply decoding vhich is the inverse of the coding program.

The first step in the decoding process is to generate a bit stream from the hexagon Information, using a hexagon-to-bit mapping process vhich is the reverse of the bit-to-hexagon map-ping process used in the encoding operation.

The bit (Information) stream is then bifurcated by the program into a high priority message bit stream and a low priority message bit stream or as many bit streams as are used in encoding the label.

It is then necessary to apply error correction to each bit stream using the error coding techniques vhich vere used in the label encoding process. For example, if Reed-Solomon coding is used, error correction on the bit stream generated by the 73- LV 10820 search program generates an output vhich is in the same format as previously described for the encoding input file. Error correction may be performed in the following sequence (Reference: Theory an<ļ Prastlce of Error Control· Codes, described above.) 5 1. Compute syndromes 2. Compute Error Locator Polynomial using Berlekamp-Massey Algorithm 3. Compute error locations using Chien search 4. Compute error magnitudes using Forr.ey's Algorithm 10

The last step is eKecuted^ only if a correctable number o£ errors has been detected from steps 2 and 3. The number of errors de-tected are also computed. If an uncorrectable number of errors is detected or an error is located in the inplied padding (des-15 cribed above), a flag is set. The specific error coding procedūra utilized in the illustrative example may be found in the Microflche Appendix at page 67 through 75, and is designated as ERRDEC.C 1Θ4 on Fig. 9. 5. Output 20

By tracking the package (by identifying its location on the conveyor) the high priority message, indicatir.g the zip code of the package destination, can be used to activate suitable rout-ing arms or conveyors to route the package to the proper truck, 25 airplane or package carrier to take the package to its destination.

Although the invention may be as used in a conveyor/ diverter system, it will be apparent that it can be used in a vide variety of information gathering, package handling and pro-duction operations in vhich it is desired to read a label on a 30 package, letter, part, machine or the like and cause a system to perform a package handling or manufacturing operation, for example, on the object bearing the label. The Invention allovs these operations to occur vith high speed, high accuracy, dealing vith a substantial amount of label information and even protect-35 ing much of that Information from being lost due to label tears and the like. 74- 10 15 20 25 30·

With reference to Fig. 9, to alternatively display the decoded message on a Computer termiņai, the program ?EXTOUT.C 185 may be employed. Program TEXTOUT.C may be found vithin the Micro fiche Appendix at pagea 76 through 78. -75- 35 LV 10820

ΤΊα. 1

LV 10820

ΤΊα. 3

ΤΊα. 4 LV 10820

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A|A J XG] A- ___ 3 -|G 3 WlW B GļW B Wl3 W 3iB W GiB B W]W B BG G B3X”XC- GX 2 - iB X Gb B G!W B W]G ΧΧ13 3 G!G T.VWB G X>XvXX' G G C- X X! 1 ~'3G 3ΒΧ 3GWGG 5 GG 3Χ7Χ BG3GEG3GG X GVGv.v 113115117119121123125 i 27:231 12 14 16 18 20 22 24 25 23 30 113I5I7I9I1 2 4 6 8 10

Tia.5 LV 10820 LV 10820 -* 200 /<98

LABEl READING PROCESS

ILLUMINATION OF THE LABEL ORTICAL SENSING OF THE REFLECTEDIMAGE PROCESSING THE REFLECTED IMAGE a. LOCATING THE TARGET (OPTIONAL) b. NORMALIZATION OF THE SENSED IMAGE (OPTIONAL) c. RESCALING THE IMAGE (OPTIONAL) 1 TWO-OIMENSIONAL CLOCK RECOVERī

i. EDGE ENHANCEMENT OPERAT10N ii. WINOOWING (OPTIONAL)

iii. TWO-DIMENSIONAL FAST FOURIER TRANSFORMATION

iv. FILTERING THE IMAGE

v. INVERSE FAST FOURIER TRANSFORMATION e. MAJOR AXIS DETERMINATION (OPTIONAL)

f. SEARCHING i. . .

ii. MAIN SEARCH LOOP g. HISTOGRAM GENERATION (OPTIONAL)

COARSE GRID DETERMI NATION AND FINAL ORlENTATION(OPT;Cf DECODING OUTPUT LV 10820

LV 10820

LV 10820

LV 10820

LV 10820

ΈΙ3.14 LV 10820 a 361 ,A| Sc μ^362

Πσ. /5 LV 10820

ΤΊ3.Ι7 LV 10820

Tig. /9 *1

Tia. 20 LV 10820

What is claimed is: 1. An optically readable label for storing encoded Information comprising a multiplicity of information-encoded polygons having at least five sides, said polygons arranged with the geometric centers of adjacent polygor.3 lying at the vertices of a predetermined tvo-dimensional array, said polygcns having one of at least two different optical properties. 2. An artjcle as recited in claim 1, vherein said array is a hexagonal array. 3. An article as recited in claim 2, vherein said hexagonal array has three axes spaced 60 degrees apart. 4. An article as recited in claim 1, vherein said polygons are substantially in the shape of jregular hexagons. 5. An article as recited in claim 1, vherein said optical properties are the colors black, vhite and gray. 6. An artiole as recited in claim 1, vherein said polygons are irregular polygons. 7. An article as recited in claims 1 or 2, further comprising a pluraiity of Concentric Rings occupyir.g ar. area on said article separate from the area occupied by said information-encoded polygons, each Concentric Ring having one of at least tvo different optica-l properties in alternating seguence. 8. An article as recited in claim 7, vherein said Concentric Rings are centrally located on said article. 9. An optically readable label for storing encoded Information comprising a multiplicity of information-encoded triangles, said triangles arranged vith the geometric centers of adjacent triangles lying at the vertices of a predetermined tvo-dimensional array, and said triangles having one of at least tvo different optical properties. 10. An article as recited in claim 9, further comprising a plurality of Concentric Rings occupylng an area on said article separate from the area occupied by said information-encoded triangles, each Concentric Ring having one of at least tvo different optical properties in alternating seguence. -76 11. An article as recited in claim 10, vherein said Concentric Rings are centrally located. Ϊ2. An optically readable label for storing encoded Information comprising a multiplicity of information-er.coded polygons, said polygons arranged with the geometric cer.ters of adjacent polygons lying at the vertices of a two-dimensional hexagonal array, and said polygons having one of at least two different optical properties. 13. An articie as recited in claim 12, vherein said polygons are substantia1ly in the shape of regular hexagons. 14. An optically readable label for storing encoded information comprising a multiplicity of information-er.coded polygcns, said polygons arranged vith the geometric cer.ters of adjacent polygons lying at the vertices of a predetermined tvo-dimensional array, and said polygons having one of at least tvo different optical properties and said array having at least three equally-spaced axes. 15. An optically readable label for storing encoded Information comprising a multiplicity of information-er.coded polygons, said polygons partially contiguously arranged vith the geometric centers of adjacent polygons lying at the vertices of a predetermined tvo-dimensional array, and said polygons having one of at least tvo different optical properties. 16. An optically readable label for storing encoded information comprising a multiplicity of information-er.coded pcly-gons, said polygons noncontiguously arranged vith the geometric centers of adjacent polygons lying at the vertices of a predetermined tvo-dimensional array, and said polygons having cne of at least tvo different optical properties. 17. An article as recited in claims 14, 15 or 16, vherein said polygons are regular polygons. 1Θ. An article as recited in claims 14, 15 or 16, vherein said polygons are irregular polygons. 19. An article as recited in claims 14, 15 or 16, further comprising a plurality of Concentric Rings occupying an 77- LV 10820 area on said article separate from the area occupied by eaid information-encoded polygons, each Concentric Ring having or.e of at least two different optical properties īn alternatlng sequer.ce. 20. An article as recited ln claim 19, vherein said S Concentric Rings are centrally located on said article. 21. An article as recited in claims 15 or 16, vherem said array is a hexagonal array. 22. An article as recited in claim 21, vherein said hexagonal array has three axes spaced 60 degrees apart. 10 23. A process for decoding a stream of digital signāls representing an electro-optically sensed label image correspcr.d-ing to a multiplicity of noncontiguously-arranged polygor.s en-coded in accordance with an encodlng process, said polygons de-fining a multiplicity of interstitial spaces among said poiygcr.s, 15 said polygons arranged with· the gecmetric centers of adjacer.t polygons lying at the vertices of a predetermined tvo-dimer.sicr.al array, and said polygons and said interstitial spaces having or.e of at least two different optical properties, comprising the steps of: 20 (a) performmg a tvo-dimensional clock recoverv on said sensed label image to obtain a recovered clock signal; (b) utilizing said recovered clock signal of step (a) to locate the geometric centers of said polygons to identify the optical properties of said polygons; and 25 (c) decoding said polygons by performing the inverso of said encoding process. 24. A process for decoding a stream of digital signāls representing an electro-optically sensed label image corresponding to a multiplicity of partially 30 contiguously-arranged polygons encoded in accordance with ar. encoding process, said polygons defining a multiplicity of interstitial spaces among said polygons, said polygons arranged with the geometric centers of adjacent polygons lying at the vertices of a predetermined two-dimensional array, and said 35 78 polygons and said interstitlal spacea having one of at least two different optical properties, comprising the steps of: (a) performing a two-dimensional clock recovery on said sensed label image to obtain a recovered clock slgnal; 5 (b) utilizing said recovered clock signal of step (a) to locate the geometric centers of said poiygons to identify the optical properties of said polygons; and (c) decoding said polygons by performing the in-verse of said encoding process. 10 25. A process as recited in claims 23 or 24, vherem said two-dimensional array is a hexagonal array. 26. A process as recited in claims 23 or 24, wherein said polygons are regular polygons. 27. A process as recited in claims 23 or 24, vherein 15 said polygons are irregular pol/gons. 28. A process as recited in claims 23 or 24, vherein said polygons are substantially in the shape of regular hexagons. 29. A process as recited in claim 23, vherem step (a) comprises the steps of: 20 (i) performing a nonlinear mapping operation on said digital signāls to-identify transitions betveen adjacent polygons and betveen po!ygons and interstitial spaces having different optical properties; (ii) performing a Fourier transformation on the 2S nonlinear mapped digital signāls to obtain a tvo-dimensior.al rep-resentation corresponding to the direction, spacing and ir.tensity of optical property transitions of said polygons; (iii) filtering said transformed nonlinear mapped digital signāls to eliminate incorrect direction and spacing of 30 optical property transitions of said polygons; and (iv) performing an inverse Fourier transformation on said filtered transformed nonlinear mapped digital signāls to obtain said recovered clock signal. 79- 35 LV 10820 30. A process as recited in claim 23, further compris-ing the step, prior to step (a), of normalizing the sensed label image to predetermined Ievels for each respective optical property of the image. 31. A process as recited in claim 23, further compris-ing the step, prior to step (a) of rescaling the image to create an image with equal horizontal and vertical magnification. 32. A process as recited in claim 29, wherein step (i) comprises creating a tvo-dimensional map of the transitions betveen adjacent polygons and betveen polygons and said inter-stitial spaces having different cptical properties by computir.g the Standard deviation of the optical properties of said image recorded by each pixel and pixels proximate each pixel of said electro-optical sensor, vherein larger Standard deviation values correspond to transition areas at the interfaces of said polygons. 33. A process as recited in claim 32, further compris-ing the step of thresholding said sensed label image at the ce.nter of each polygon located in step (b) to determine the respective optical properties of said polygcr.s. 34. A process as recited in claim 33, wherein the step of determinlng the thresholds of said sensed label image is per-formed by constructing histograms representing the respective optical properties of said polygcns. 35. A process as recited in claims 23, 29 or 34, vherein step (b) comprises: (i) performmg an initialization step vhieh searches the tvo-dimensional recovered clock signal obtained in step (a) vithin a predetermined area of said signal, to identify the position of greatest intensity; and (ii) performing a search continuation loop step vhieh searches the tvo-dimensional recovered clock signal over the entire recovered clock signal starting from the position of greatest intensity in step (1) and looping to each adjacent position of next greatest intensity, vherein each identified position corresponds to the center of a polygon. 36. A process as recited in jlaim 35, vherein said image sensed by said electro-optical sensor includes an acqui-sition target comprising a plurality of Concentric Rings of different, alternating optical properties and vherein the first step of the process is locating said acquisition target by fil-tering said digita1'signa1s and correlating said digital signāls to a signal of predetermined frequency. 37. A process as recited in claim 24, vherein step <a) comprises the steps of: (i) performing a nonlinear mapping operation on said digital signāls to identify transitions betveen adjacent polygons and betveen polygons and said interstitial spaces havmg different optical properties; (ii) performing a Fourier transformation on the nonlinear mapped digital signāls to obtain a tvo*dimensional rep-resentation corresponding to the direction, spacing and intensity of optical property transitions of said polygons; (lii) filtering said transforned nonlinear mapped digital signāls to eliminate incorrect direction and spacing of optical property transitions of said polygons; and (iv) performing an inverse Fourier transformation on said filtered transformed nonlinear mapped digital signāls to obtain said recovered clock signal. 38. A process as recited in claim 24, further compns-ing the step, prior to step (a), of normalizing the sensed label image to predetermined Ievels for each respective optical prop-erty of the image. 39. A process as recited in claim 24, further comprising the step, prior to step (a) of rescaling the image to create an image vith equal horizontal and vertical magnification. 40. A process as recited in claim 37, vherein step (i) comprises creating a tvo-dlmensional map of the transitions be- -81- LV 10820 tween adjacent polygons and betveen polygons and sald interstitial spaces havlng different optical properties by computing the Standard devlation of the optical properties of said image recorded by each pixel and pixels proximate each pixel of said electro-optical sensor, vherein larger Standard deviation values corres-pond to transition areas at the interfaces of said polygons. 41. A process as recited in claim 40, further compris-ing the step of thresholding said sensed label image at the center of each polygon located in step (b) to determine the respective optical properties of said polygons. 42. A process as recited in claim 41, vherein the step of determining the thresholds of said sensed label image is per-formed by constructing histograms representing the respective optical properties of said polygons. 43. A process as recited in claims 24, 37 or 42, vherein step (b) comprises: (i) performing an initialization step vhich searches the tvo-dimensional recovered clock signal obtamed ir. step (a) vithin a predetermined area of said signal, to identify the position of greatest intensity; and (ii) performing a search continuation Loop step vhich searches the tvo-dimensional recovered clock signal over the entlre recovered clock signal startlng from the position of greatest intensity in step (i) and looping to each adjacent position of r.ext greatest intensity, vherein each identified position corresponds to the center of a poiygon. 44. A process as recited in claim 43, vherein said image sensed by said electro-optical sensor includes an acguisi-tion target compiising a pluralitV of Concentric Rings of different, alternating optical properties and vherein the first step of the process is locating said acguisition target by filtering said digital signāls and cobrelating said digital signāls to a signal of predetermined f/f:equency. -Θ2- 45 A combinatlon optlcal mark sensing and decoding system, comprising: (a) an optically readable labai for storing en-coded Information comprising a multiplicity of information-ancodad polygons having at least five sides, said polygons ar-rangad with the geometric canters of adjacent polygons lying at tha vertices of a predetermined tvo-dimensional array and said polygons having one of at least two different optical properties; (b) means for illuminating a predetermined area; (c) means for optically imaging said predetermined illuminated area through which said label is arranged to pass and ger.erating analog electrical signāls corresponding to the intensities of light reflected from said polygons and strik-ing each pixel of said Imaging means; (d) means for converting said analog electrical signāls into a seguenced digital bit stream corresponding to the intensities of light recorded by said pixels of said imaging means; (e) means for storing said digital bit stream for subseguent decoding of said label; and (f) means for decoding said digital bit stream, said decoding means producing an electrical output representative of the encoded Information. 46. An apparatus as recited in claim 45, wherein said optically readable label further comprises a plurality of Concen-tric Rings, said Concentric Rings having alternating optical properties corresponding to at least tvo of the optical properties of said polygons. 47, A combination optical mark sensing and decoding system, comprising: (a) an optically readable label for storing encoded Information comprising a multiplicity of information-encoded polygons, said polygons arranged with the geometric centers of adjacent polygons lying at the vertices of a tvo- -83- LV 10820 dimensional hexagonal array, and aald polygons having one of at least two different optical properties; (b) means for illuminating a predetermined area; (c) means for optlcally imaging said predetermined illuminated area through which said label is arranged to pass and generating analog electrical signāls corresponding to the intensities of light reflected from said polygons and strik-ing each pixel of said imaging means; (d) means for converting said analog electrical signāls into a sequenced digital bit stream corresponding to the intensities of light recorded by said pixels of said imaging means; (e) means for storing said digital bit stream for subseguent decoding of said label; and (f) means for decoding said digital bit stream, said decoding means producing an electrical output representative of the encoded Information. 43. An apparatus as recited in claim 47, vherein said optically readable label further comprises a plurality of Concen-tric Rings, said Concentric Rings having alternating optical properties corresponding to at least tvo of the optical properties of said polygons. 49. An apparatus as recited in claim 48, vherein said polygons are substantially in the shape of a regular hexagon. 50. A combination optical mark sensing and decoding system, comprising: (a) an optically readable label for storing encoded Information comprising a multiplicity of information-encoded triangles, said triangles arranged with the geometrlc centers of adjacent triangles lying at the vertices of a predetermined two-dimensional array, and said triangles having one of at least two different optical properties; (b) means for illuminating a predetermined area; (c) Tneans for optically imaging said predetermined illuminated area through which said label is arranged to pass and generating analog electrical signāls corresponding to -84- 5 the intensitles of light reflected from said triangles and strik-ing each pixel of said imaging means; (d) means for converting said analog electrical signāls into a sequenced digital bit stream corresponding to the intensitles of light recorded by said pixels of said imaging means; (e) means for storing said digital bit stream for subsequent decoding of said label; and 10 (f) means for decoding said digital bit stream, said decoding means producing an electrical output representative of the encoded Information.

1S 51. An apparatus as recited in claim SO, vherein said optically readable label further comprises a plurality of Concen-tric Rings, said Concentric Rings having alternating optical prop-erties corresponding to at least tvo of the optical properties of said polygons. 52. A combination optical mark senaing and decoding sy5tem, comprising: 20 (a) an optically readable label for storing encoded Information comprising a multiplicity of information-encoded polygons, said polygons nonconticruously-arranged vith the geometnc centers of adjacent polygons lying at the vertices of a predeter-mined two-dimensional array, said polygons having one of at leas. tvo different optical properties; 25 (b) means for illuminating a predetermined area; <c) means for optically imaging said predeter- 30 mined illuminated area through vhich said label is arranged to pass and generating analog electrical signāls corresponding to the irtensities of light reflected from said polygons and striking each pixel of said imaging means; (d) means for converting said analog electrical signāls into a seguenced digital bit stream corresponding to the intensitles of light recorded by said pixels of said imaging means; -85- 35 LV 10820 ring said dlgital bit stream for ; and oding said digital bit stream, electrical output representative cited in claim 52, vherein said comprises a plurality of Concen-having alternating optical ast two of the optical properties (e) meana for eto subsequent decoding of said labai (f) means for dec said decoding means producing an of the encoded information. 53. An apparatus as re optically readable label further trio Rings, said Concentric Rings properties corresponding to at le of said polygons. 54 A combination optical mark sensing and decoding system, compnsing: (a) an optically readable label for storing encoded information comprising a multiplicity of information-encoded polygons, said polygons, partia11y contiguously-arranged with the geometric centers of adjacent polygons lying at the vertices of a predetermined two-dimensional array, said polygons having one of at least tvo different optical properties; (b) means for illuminating a predetermined area; (c) means for optically imaging said predetermined illuminated area through vhich said label is arra.nged to pass and generating analog electrical signāls corresponding to the intensities of light reflected from said polygons and strik-ing each pixel of said imaging means; (d) means for converting said analog electrical signāls into a seguenced digital bit stream corresponding to the intensities of light recorded by said pixels of said imaging means; (e) means for storing said digital bit stream for subsequent decoding of said label; and (f) means for decoding said digital bit stream, said decoding means producing an electrical output representative of the encoded information. 55. An apparatus as recited in claim 54, vherein said optically readable label further comprises a plurality of Concen- 86- tric Rings, aaid Concentric Rings having alternating optical properties corresponding to at least two of the optical propsrties of said pdlygoQ3. 56. An apparatus for decoding a stream of digital sig-5 nals representir.g an electro-optically sensed label image of a multiplicity of noncontiguosly-arranged polygons encoded in ac-cordance with an encoding process, said polygons defining a mul-tiplicity of interstitial spaces among said polygons, said poly-gons arranged with the geometric centers of adjacent polygons 10 lying at the vertices of a predetermined tvo-dimensional array, and said polygons and said interstitial spaces having one of at least two different optical properties, comprising: (a) means for performing a two-dimensional clock re-covery on said sensed label image to obtain a recovered clock 15 signal; (b) means for utilizing said recovered clock signal of step (a), to locate the geonetric centers of said polygcns and identify the optical properties cf said polygons; and (c) means for decoding said polygons by performing the 20 inverss of said encoding process. 57 An apparatus for decoding a stream of digital signāls representing an electro-optically sensed label image of a multlplicity of noncontiguously-arranged polygons encoded in ac-cordance with an encoding process, said polygons defining a multi-25 plicity of interstitial spaces among said polygons, said polygons arranged vith the geometnc centers of adjacent polygons lymg at the vertices of a predetermined two-dimensional array, and said polygons and said interstitial spaces having one of at least tvo different optical properties, comprising: 30. (a) means for performing a nonlinear mapping operation on said digital signāls to identify transitions betveen adjacent polygons having different optical properties; (b) means for performing a Fourier transiormation on the nonlinear mapped digital signāls to obtain a two-dimensional -87 35 LV 10820 representation corresponding to the direction, spacing and in-tensity of optical property transitiona of aaid polygons; (c) means for filtering aaid transformed nonlinear mapped digital signālā to eliminate incorract direction and spacing -of optical property transitiona of aaid polygons; (d) means for performing an inversa Fourier transformatlon of aaid filtered transformed nonlinear mapped digital aignala to obtain said recovered clock signal; (e) meana for utilizing said recovered clock signal to locate the geometric centera of said polygons and to identify the optical properties of said polygons; and (f) means for decoding said polygons by performing the inverse of said encoding process for said polygons. 58. λη apparatua as recited in claim 57, vherein said nonlinear mapping means comprises meana for creating a two« dimensional map of the transitiona betveen adjacent polygons having different optical properties by computing the Standard deviation of the optical properties of said image recorded by each pixel and pixels proximate each pixel of said electro-optical sensor, vherein larger Standard deviation values corres-pond to transition areas at the interfaces of polygons. 59. An apparatua as recited in claim 57, further ccm-prising means for normalizing the ser.sed label image to predeter mined optimums for each respective optical property of the image prior to performing the nonlinear mapping operation. 60. An apparatus as recited in claim 57, further com-prising means for rescaling the sensed label image to create an image vith equal horizontal and vertical magnification prior to performing the nonlinear mapping operation. 61. An apparatus as recited in claim 58, further com-prising means for thresholding said sensed label image at the center cf each polygon located by means (e) to determine the respective optical properties of said polygons. -88- 62. An apparatus as recited ln claim 61, vherein the threaholding means further comprises means for constructing hiatograms representing the respective optical propertiea of aaid polygona. S 63. An apparatua as recited in claima 56, 57 or 62, vherein aaid searching means comprises: (i) initialization meana to aearch aaid tvo-dimenaional recovered clock aignal vithin a predetermined area of aaid aignal, to identify the position of greateat intenaity; and 10 (ii) a aearch contir.uation loop means to search aaid two-dimensional recovered clock aignal over the entire recovered clock aignal starting from the position of greateat in-tensity obtained by means (i) and looping to each adjacent position of next greateat intenaity, vherein-each identified position 15 corresponda to the center of a polygon. 64. An apparatus as recited in claim 63, vherein aaid image sensed by aaid electro-optical sensor includes an acguisi-tion target comprising a plurality of Concentric Rings of dif-ferent, alternatmg optical propertiea and means for locating 20 aaid acquisition target by filtenng aaid digital signālā and correlating aaid digital signāls to a signal of predetermined frequency. 65· An apparatus for decoding a stream of digital signāls representing an electro-optically sensed label image of a 25 multiplicity of partiaily contiguously-arranged polygons encoded in accordance vith an encoding process, aaid polygons defimng a multiplicity of interstitial spaces among aaid polygons, said polygons arranged vith the geometric centera of adjacent polygons lying at the vertices of a predetermined tvo-dimensional array, 30 and aaid polygons and said interstitial spaces having one of at least tvo different optical propertiea, comprising: (a) means for performing a tvo-dimensional clock recovery on aaid sensed label image to obtain a recovered clock signal; -89- 35 LV 10820 (b) means for utilizing said recovered clock signal to locate the geometric centers of said polygons and identi£y the optical properties of said polygons; and (c) means for decoding said polygons by perform-ing the inverse of said encoding process. 66. An apparatus for decoding a stream of digital signāls representing an eiectro-optically sensed label image of a multiplicity of partially contiguously-arranged polygons definmg a multiplicity of interstitial spaces among said polygons, said polygons arranged with the geometric centers of adjacent polygons lying at the vertices of a predetermined two-dimensicnal array, said polygons and said interstitial spaces having or.e of at least two different optical properties, comprising: (a) means for performing a nonlinear mapping operation on said digital signāls to identify transitions betveen adjacent polygons having different optical properties; (b) means for performing a Fourier transiormation on the nonlinear mapped digital signāls to obtain a two-dimensional representation corresponding to the direction, spac-ing and intensity of optical property transitions of said poly-gons; (c) means for filtering said trar.sformed nonlinear mapped digital signāls to eliminate incorrect direction and spacing of optical property transitions of said polygor.s· (d) means for performing an inverse Fourier transformation of said filtered transformed non-linear mapped digital signāls to obtain said recovered clock signal; (e) means for utilizing said recovered clock signal to locate the geometric centers of said pol/gcns and identify the optical properties of said polygons; and (f) means for decoding said polygons by performing the inverse of said encoding process for said polygons. 67. An apparatus as recited in ciaim 66, vherein said nonlinear mapping means comprises means for creating a tvo-dimensional map of the transitions betveen adjacent polygons hav- -90- ing different optical properties by computing the Standard devia-tion of the optical properties of said image recorded by each pixel and pixels proximate each pixel of said electro-optical sensor, vherein larger Standard deviation values correspond to transition areas at the interfaces of polygons. 68. An apparatus as recited īn claim 66, further com-prising means for normalizing the sensed label image to predeter-mined optimums for each respective optical property of the image prior to said nonllnear mapping operation. 69. An apparatus as recited in claim 66, further com-prising means for rescaling the sensed label image to create ar. image vith equal horizontal and vertical magnification prior to said nonlinear mapping operation. 70. An apparatus as recited in claim 67, further com-prising means for thresholding said sensed label image at th'e center of each polygon located by means (e) to determine the respective optical properties of said polygons. 71. An apparatus as recited in claim 7C, vherein the thresholding means further comprises means for constructing his-tograms representing the respective optical properties of said polygons. 72. An apparatus as recited in claims 65, 66 or 71, vherein said searching means comprises: (i) initialization means to search said tvo-dimensional recovered clock signal vithin a predetermined area of said signal to identify the position of greatest ir.ter.sity; ar.d (ii) a search continuation loop means to search said tvo-dimensional recovered clock signal over the entire recovered clock signal from the position of greatest intensity ob-tained by means (i) and looping to each adjacent position of next greatest intensity, vherein each identified position corresponds to the center of a polygon. 73. An apparatus as recited in claim 72, vherein said image sensed by said electro-optical sensor includes an acguisi-tion target comprising a plurality of Concentric Rings of dif-ferent, alternating optical properties and means for locating -91- LV 10820 said acquisition target by filtering eaid digital signāls and correlating aaid digital signāls to a eignal of predetermined freguency. 74. A process for encoding Information in an optically readabla labai comprising a multiplicity of partlally contigtiously-arranged polygons defining a multiplicity of m-terstitial spaces among said polygons, said polygons arranged vith the geometric centers of adjacent polygons lying at the vertices of a predetermined tvo-dimensional array, and said polygons and said interstitial spaces having one of at least tvo different optical properties, comprising the steps of: (a) assigning one of at least two optical properties to each polygon to create a plurality of partially contiguously-arranged polygons having different optical properties; (b) encoding the Information by ordering the polygons in a predetermined seguence; and (c) printing each polygon in its assigned optical property. 75. A process as recited in claim 74, further ccnpris-ing the steps of: (d) assigning a plurality of dots in a dot matrix to define the optical property of each polygon; and (e) printing said plurality of dots. 76. A process for encoding Information in an opticaliy readable label comprising a multiplicity of contiguously-arranged polygons, said polygons arranged vith the geometric centers of adjacent polygons lying at the vertices of a predetermined two-dimensional array, said polygons having one of at least tvo different optical properties, comprising the steps of: (a) assigning one of at least tvo optical properties to each polygon to create a plurality of contiguously-arranged polygons having different optical properties; (b) encoding the Information by ordering the poly-gons in a predetermined seguence; and -92- (c) printing each polygon in lts assigned optical property. 77. A procesa as recited in claim 76, further compris- ing the steps of: (d) assigning a plurality of dots in a dot matnx to define the optical property of each polygon; and (e) printing said plurality of dots. 78. A process for encoding Information in an opticaily readable label comprising a multiplicity of noncontiguously-arranged polygons defining a multiplicity of interstitial spaces among said polygons, said polygons arranged with the geometric centers of adjacent polygons lying at the vertices of a predeter-mined tvo-dimensior.al array, and said polygons and said ir.tersti-tial spaces having one of at least two different optical prcper-ties, comprising the steps of: (a) assigning one of at least two optical prop-erties to each polygon to create a plurality of noncontig\iously-arranged polygons having different optical properties; (b) encoding the information by ordering the poiy-gons in a predetermined sequence; and (c) printing each polygon in its assigned optical property. 79. A process as recited in claim 78, further compns* ing the steps of: (d) assigning a piurality of dots in a dot matrix to define the optical property of each polygon; and (e) printing said plurality of dots. 80. A process as recited in claims 74, 76 or 78, vherein step (b) includes the step of mapping groups of tvo or mora polygons in predetermined geographical areas on said article. 81. A process as recited in claim 80, further comprising the steps of dividing the information being encoded into at least tvo categories of higher and lover priorities, and encoding said higher and lover priority information in separate, predetermined geographical areas. -93- LV 10820 82. A process as recited ln claim 81, further compris-ing the step of separately applying error detection information to said higher and lover priority Information. 83. A process as recited in claims 74, 76 or 78, further compriaing the step of encoding a plurality of selected poiygons with error detection Information and ir.terposing said error-detection-encoded polygons among said polygons. 84. A process as recited in claim 82, further compns-ing the step of utilizing said error detection information to correct errors in the information retrieved from said article. 85. A process as recited in claim 83, vherein said error detection information may be utilized to correct errors m the information retrieved from said article. 86. A process as recited in claims 74, 76 or 78, further comprising the step of structuring said encoding step t'o optlmize the number of polygons having different optical prop-erties. 87 A process of storing and retrieving data, comprising the steps of: {a) printing on a label a multipiicity of par-tially contiguously-arranged polygons encoded in accordance with an encoding process, said polygons defining a multiplicity of interstitial spaces among said polygons, said polygons arranged with the geometric centers of adjacent polygons lying at the vertices of a predetermined two-dimensional array, and said polygons and said interstitial spaces having one of at least tvo different optical properties; (b) illuminating said label; (c) optical.ly sensing light reflected from said polygons with an electro-optlcal sensor; (d) generating analog electrical signāls cor-responding to the intensities of light reflected from said optical properties as sensed by individual pixels of said sensor; (e) converting said analog electrical signāls into seguenced digital signāls; -94- (f) storing said digital signāls ln a storage medium connected to a Computer to form a replica of said digital signāls in said storage medium; (g) decoding said replica of said digital signāls to retrieve the characteri stics cf the intensities, locatior.s and orientations of the individual optical properties of said poly-gons; and (h) generating a digital bit stream output from the Computer representing the decoded information represer.ted by the polygons. 88. A process as recited in claim 87, vherein said label further comprises a plurality of centrally-located Concer.-tric Rings, said Concentric Rings having alternating optical properties corresponding to at least two of the optical properties of said polygons. 89 A process of storing and retrieving data, compris-ing the steps of: (a) pnnting on a label a multiplicity of noncontiguously-arranged polygor.s encoded in accordance vith ar. encoding process, said polygons defining a multipiicity of in-terstitial spaces among said polygons, said polygons arranged vith the geometric centers of ad;acent polygons lying at the vertices of a predetermined tvo-dimensional array, and said polygons and said interstitial spaces having one of at least tvo different optical properties; (b) i1luminating said label; (c) optically sensing light reflected from said polygons vith an electro-optical sensor; (d) generating analog electrical signāls corresponding to the intensities of light reflected from said optical properties as sensed by individual pixels of said sensor; (e) converting said analog electrical signāls lnto seguenced digital signāls;' -95 LV 10820 (£) storing sald digital signāls in a storage medium connected to a Computer to form a replica of said digital signāls in said storage medium; (g) decoding said replica of said digital signāls to retrieve the characteristics of the intensities, locations and orientations of the individual optical properties of said poly-gons; and (h) generating a digital bit otream output from the Computer representing the decoded Information represer.ted by the polygons. 90. A process as recited in claim 89/ vherein said labai further comprises a plurality of centrally«located Con-centric

Rings, said Concentric Rings having alternating optical properties corresponding to at least two of the optical properties of said polygons. 91. A process of storing and retrieving data, compris-ing the steps of: (a) printing on a label a multiplicity of contiguously-arranged polygons encoded in accordance with an en-coding process, said polygons arranged with the geometric centers of adjacent polygons lying at the vertices of a predetermmed two-dimensional array, and said polygons and said interstitial spaces having one of at least two different optical properties, (b) i1luminating said label; (c) optically sensing light reflected from said polygons with an electro-optical sensor; (d) generating analog electrical signāls corresponding to the intensities of light reflected from said optical properties as sensed by individual pixels of said sensor; (e) converting said analog electrical signāls into sequenced digital signāls; (f) storing said digital signāls in a storage medium connected to a Computer to form a replica of said digital signāls in said storage medium; -96- (g) decoding said replica o£ said digital signāls to retrieve the characteristics of the ir.tensities, locations and orientations of the individual optical properties of said poly-gons; and (h) generating a diaital bit stream output from the Computer representing the decoded Information represente d by the polygons. 92. A process as recited in claim 91, vherein said label further comprises a plurality of centrally-located Concen-tric Rings, said Concentric Rings having alternating optical properties corresponding to at least two of the optical proper-ties of said polygons. -97- LV 10820

ABSTRACT Ot THE INVENTION

The article of the invention is an optically readable labai for storing encoded Information, aaid labai comprieing a data array of a multiplicity of information-encoded polyg©n3 5 arranged in a predetermined gaomatric pattarn, and said poly-gons having at least tvo different optical properties. λ process for encoding Information in an optically. readable data array comprised of information-encoded polygons by aeeigning optical properties to individual polygor.s in a 10 predetermined pattern, ordering the polygone in a predetermined sequence, and printing the polygons with at least twc optical properties. A process for retrieving Information by optically scan- ning a data array of information-encoded polygons, preferably 15 hexagons, creating an optical replica of the digital bit stream representative of the optical properties of the information-encoded polygons, decoding that optical replica and retrieving the decoded bit stream. A system for performing the foregoing encoding and 20 decoding processes. 25 30 35

Claims (92)

Formula 1: Optically readable label for storing coded information containing an informally coded polygon set, wherein: the polygons have at least five edges and are arranged so that the adjacent polygonal geometric centers are at predetermined two-dimensional grid vertices, and the polygons have one polygon of at least two different optical characteristics. 2. The label of claim 1, wherein the grid is a hexagonal grid. 3. A label as claimed in claim 2, characterized in that the grid has 3 axes with a 60 degree angle between adjacent axes. 4. A label as claimed in claim 1, characterized in that the polygons are in the shape of a regular hexagon. 5. The label of claim 1, wherein the optical features are black, white and gray. 6. A label as claimed in claim 1, wherein the polygon is irregular. 7. A label as claimed in claim 1 or 2, comprising a set of concentric rings and occupying an area of the label separated from the area occupied by the information coded polygon, the concentric rings alternately having one of the two optical features . 1 8. A label as claimed in claim 7, wherein the concentric rings are placed in the center of the label. An optically readable label for storing coded information containing an informatively coded set of rectangles and arranged so that the geometric centers of adjacent rectangles are located at predetermined two-dimensional grid vertices, and the rectangles have one of at least two different optical characteristics. 10. The label of claim 9, wherein. characterized in that it comprises a set of concentric rings and occupies an area of the label separated from the area occupied by the informatively coded rectangle, the concentric rings alternately having one of the two optical features. 11. A label as claimed in claim 10, wherein the concentric rings are positioned at the center of the label. An optically readable label for storing coded information comprising an informally encoded polygon set, further arranged so that the geometric centers of adjacent polygons are located at predetermined two-dimensional grid vertices, and the polygons have one of at least two different optical characteristics. 13. A label as claimed in claim 12, characterized in that the polygons are in the shape of a regular hexagon. 14. An optically readable label for storing coded information containing an informally coded polygon set, further arranged so that the geometric centers of adjacent polygons are located at predetermined two-dimensional grid vertices, and the polygons have at least two different optical features and the grid has at least three axes at equal angles. 2 LV 10820 An optically readable label for storing coded information comprising an informally coded polygon of partially bound polygons, further arranged so that the geometric centers of adjacent polygons are located at predetermined two-dimensional grid vertices, and the polygons have one of at least two different optical features. An optically readable label for storing coded information comprising an informally coded non-polygonal set, further arranged in such a way that the geometric centers of adjacent polygons are located at predetermined two-dimensional grid vertices, and the polygons have one of at least two different optical characteristics. 17. A label as claimed in claim 14, 15 or 16, wherein the polygon is regular. 18. A label as claimed in claim 14, 15 or 16, wherein the polygon is irregular. 19. A label as claimed in claim 14, 15 or 16, comprising a set of concentric rings and occupying an area of the label separated from the area occupied by the informatively coded polygon, the concentric rings alternately having one of two optical features. 20. A label as claimed in claim 19, wherein the concentric rings are placed in the center of the label. 21. A label according to claim 15 or 16, wherein the grid is a hexagonal grid. 22. A label as claimed in claim 21, wherein the grid has 3 axes with a 60 degree angle between adjacent axes. 23. A method for decoding the flow of digital signals corresponding to a scanned label image of an optical reader formed by a defined coded set of non-polygonal polygons having different distances between polygons and 3 adjacent polygons at predetermined two-dimensional grid vertices, and polygons and gaps having at least one of at least two different optical features, characterized in that: (a) performing two-dimensional synchronous reconstruction of the image to produce a synchronously reconstructed signal; (b) using the reconstructed synchronous signal obtained in step (a) to identify the optical properties of said polygons; (c) decoding said polygons; by inversion of this polygon coding process. 24. A method for decoding the flow of digital signals corresponding to a scanned label image of an optical reader consisting of a set of coded semi-connected polygons that have different distances between polygons and the geometric centers of adjacent polygons at predetermined two-dimensional grid vertices, and polygons and polygons; the gaps between them have one of at least two different optical characteristics. characterized in that: (a) performing two-dimensional synchronous reconstruction of the image to produce a synchronously reconstructed signal; (b) using the reconstructed synchronous signal obtained in step (a) to identify the optical properties of said polygons; (c) decoding said polygons in an inversion of said polygon coding process. 25. A method according to claim 23 or 24, wherein said two-dimensional grid is a hexagonal grid. 26. The method of claim 23 or 24, wherein said polygon is a regular polygon. 27. The method of claim 23 or 24, wherein said polygons are irregular polygons. 4 LV 10820 28. A method according to claim 23 or 24, wherein said polygon is based on a regular hexagon. 29. The method of claim 23, wherein step (a) comprises: (i) a digital signal nonlinear mapping operation for determining transitions between adjacent polygons as well as between polygons and their separating gaps with different optical characteristics; (ii) a Fourier transformation of non-linearly mapped digital signals to obtain two-dimensional nonlinear coordinates corresponding to the direction, position and intensity of the transitions of said polygons; (iii) filtering the modified nonlinear mapped signals to prevent erroneous data on the direction and positioning of said polygon optical properties transitions; (iv) reverse Fourier transformation of filtered nonlinear digital signals to restore the synchronous signal. 30. A method according to claim 23, characterized in that, prior to step (a), each of the optical features of the image of the scanned label is normalized to a predetermined level. 31. The method of claim 23, wherein the step (a) is to adjust the scale of the image to obtain an image with the same magnification in the horizontal and vertical directions. . 32. The method of claim 29, wherein step (i) provides for the creation of a two-dimensional map for transitions between adjacent polygons as well as between polygons and their separating gaps with different optical characteristics, calculating the optical characteristics of the image read by the optical reader. deviations between each pixel and its adjacent pixels, with the largest standard deviations corresponding to transition zones to the polygon boundaries. 33. The method of claim 32, further comprising the step of determining, at a step (b), the threshold of each polygon center corresponding to the scanned image of the label to determine the respective optical properties of said polygon. 34. The method of claim 33, wherein the scanned label image thresholds are determined by creating histograms corresponding to the optical properties of said polygons. 5 35. A method as claimed in claim 23, 29 or 34, wherein step (b) comprises: (i) an initialization step in which, in determining the location of the highest brightness, it browses the steps of (a) in the two-dimensional synchronous reconstruction signals in said area of said polygon set to determine the largest signal intensity location; (ii) a re-browsing cycle that browses the signals defined in step (a) in the two-dimensional synchronous reconstruction across the whole of said signals, starting with the highest intensity site determined in step (i), and browsing each adjacent major brightness location, thereby identifying each polygon center. 36. The method of claim 35, wherein the image scanned by the optical reader comprises a targeting tag comprised of a concentric ring with different alternately spaced optical features, wherein the first step of the method is to find said target by filtering digital signals and comparing said target. said digital signals with a pre-selected frequency signal. 37. The method of claim 24, wherein step (a) comprises: (i) a digital signal non-linear mapping operation for determining transitions between adjacent polygons as well as between polygons and their separating gaps with different optical characteristics; (ii) a Fourier transformation of non-linearly mapped digital signals in order to obtain two-dimensional nonlinear coordinates corresponding to the direction, position and intensity of the transitions of said polygons; (iii) filtering the modified nonlinear mapping signals to prevent erroneous data on the direction and positioning of said polygon optical properties transitions; (iv) reverse Fourier transformation of filtered nonlinear digital signals to restore the synchronous signal. 38. The method of claim 24, wherein prior to step (a) normalizing each optical feature of the scanned label image to a predetermined level. 39. The method of claim 24, wherein the step (a) is to adjust the scale of the image to obtain an image with the same magnification in a horizontal and vertical direction. 40. The method of claim 37, wherein step (i) provides a two-dimensional map for transitions between adjacent polygons as well as between polygons and their separating gaps with different optical characteristics of the LV 10820, the optical readers of the image being read The features of a standard deviation between each pixel and its adjacent pixels, along with the larger standard deviations, correspond to the transition zones to the boundaries of said polygons. 41. The method of claim 40, further comprising the step of determining, at step (b), the threshold of each polygon center corresponding to the scanned image of the label to determine the respective optical properties of said polygon. 42. The method of claim 41, wherein the scanned label image thresholds are determined by creating histograms corresponding to the optical properties of said polygons. 43. A method as claimed in claim 24, 37 or 42, wherein step (b) comprises: (i) an initialization step in which, in determining the location of the highest brightness, it browses the steps defined in step (a) for two-dimensional synchronous reconstruction signals in said area of said polygon set to determine the largest signal intensity location; (ii) a re-browsing cycle that browses the signals defined in step (a) in the two-dimensional synchronous reconstruction across the whole of said signals, starting with the highest intensity site determined in step (i), and browsing each adjacent major brightness location, thereby identifying the center of each polygon. 44. The method of claim 43, wherein the image scanned by the optical reader comprises a targeting tag comprised of a concentric ring with different alternating optical features, wherein the first step of the method is to find said target by filtering digital signals and comparing said target. said digital signals with a pre-selected frequency signal. 45. Combined system for reading and decoding optical features. which includes: (a) an optically readable label for storing coded information containing an informally coded polygon set, with the polygons having at least five edges and arranged so that the adjacent polygonal geometry centers at predetermined two-dimensional grid vertices and polygons have one at least two different optical characteristics; (B) a means for illuminating a previously intended area; (c) means for optical scanning of said area by providing said label to be displaced by said area and generating analog electrical signals corresponding to said light reflected by said polygons and falling on each optical pixel of the optical scanner; (d) means for converting analog signals into a sequential binary number stream for further label decoding; (e) means for storing said binary number flow for subsequent decoding of the label; (f) means for decoding said binary number flow, which provides an outgoing electrical signal corresponding to the encoded information. 46. The system of claim 45, wherein the optically readable label further comprises a set of concentric rings in which each concentric ring alternately exhibits one of at least two optical properties of said polygons. 47. A combined system for reading and decoding optical features. comprising: (a) an optically readable label for storing coded information containing an informally coded polygon set, the geometric centers of adjacent polygons being located at predetermined two-dimensional grid vertices, and the polygons having one of at least two different optical characteristics; (b) a means for illuminating a predetermined area; (c) means for optical scanning of said area by providing said label to be displaced by said area and generating analog electrical signals corresponding to said light reflected by said polygons and falling on each optical pixel of the optical scanner; (d) means for converting analog signals into a sequential binary number stream for further label decoding; (e) means for storing said binary number flow for subsequent decoding of the label; (f) means for decoding said binary number flow, which provides an outgoing electrical signal corresponding to the encoded information. 8 LV 10820 48. The system of claim 47, wherein the optically readable label further comprises a set of concentric rings in which each concentric ring alternately exhibits one of at least two optical properties of said polygons. 49. The system of claim 48, wherein the polygon is substantially a regular hexagon. 50. A combined system for reading and decoding optical features. comprising: (a) an optically readable label for storing coded information containing an informally coded triangle, in addition: the geometric centers of adjacent triangles are located at predetermined two-dimensional grid vertices, and the triangles have one of at least two different optical characteristics; (b) a means for illuminating a predetermined area; (c) means for optical scanning of said area by providing said label to be moved over said area and generating analog electrical signals corresponding to the intensity of light reflected from said triangles and falling on each pixel of the optical scanner; (d) means for converting analog signals into a sequential binary number stream for further label decoding; (e) means for storing said binary number flow for subsequent decoding of the label; (f) means for decoding said binary number flow, which provides an outgoing electrical signal corresponding to the encoded information. The system of claim 50, wherein the optically readable label further comprises a set of concentric rings in which each concentric ring alternately exhibits one of at least two optical properties of said polygons. 52. Combined system for reading and decoding optical features. comprising: (a) an optically readable label for storing coded information containing an informally coded non-polygonal set, wherein: the geometric centers of the adjacent polygons are located at predetermined two-dimensional grid vertices, and the polygons have one of at least two different optical characteristics; (b) a means for illuminating a predetermined area; (c) means for optical scanning of said area by providing said label to be displaced by said area and generating analog electrical signals corresponding to said light reflected by said polygons and falling on each optical pixel of the optical scanner; (d) means for converting analog signals into a sequential binary in a number stream for further label decoding; (e) means for storing said binary number flow for subsequent decoding of the label; (f) means for decoding said binary number flow, which provides an outgoing electrical signal corresponding to the encoded information. 53. The system of claim 52, wherein the optically readable label further comprises a set of concentric rings in which each concentric ring alternately exhibits one of at least two optical properties of said polygons. 54. Combined system for reading and decoding optical features. comprising: (a) an optically readable label for storing coded information containing an informally encoded set of polygons, the geometric centers of adjacent polygons being located at predetermined two-dimensional grid vertices, and the polygons having one of at least two different optical characteristics; (b) a means for illuminating a predetermined area; (c) means for optical scanning of said area, providing for said label to be moved over said area and generating analog electrical signals corresponding to said light intensity reflected from said polygons and each optical pixel of the optical scanner; (d) means for converting analog signals into a sequential binary number stream for further label decoding; 10 EN 10820 (e) means for storing a binary flow of numbers for subsequent decoding of the label; (f) means for decoding said binary number flow, which provides an outgoing electrical signal corresponding to the encoded information. The system of claim 54, wherein the optically readable label further comprises a set of concentric rings in which each concentric ring alternately exhibits one of at least two optical properties of said polygons. 56. An apparatus for decoding the flow of digital signals corresponding to a set of scrambled, non-spaced polygons scrambled by the optical reader, wherein: the polygons have different distances and are arranged so that adjacent polygonal geometric centers are at predetermined two-dimensional grid vertices, and polygons; as well as having gaps therein one of at least two different optical features, characterized in that it comprises: (a) a means for performing two-dimensional synchronous reconstruction of the image to determine the coordinates and brightness of the optical features; (b) a means for performing brightness scanning of the optical properties determined in step (a) to identify polygon optical properties; (c) means for decoding said polygons in an inversion of said polygon coding process. 57. An apparatus for decoding the flow of digital signals corresponding to a scanned coded set of unpolished polygons of the optical reader, wherein: the polygons have different distances and are arranged such that the adjacent polygonal geometric centers are at predetermined two-dimensional grid vertices, and polygons as the gaps between them also have one of at least two different optical features, characterized in that it comprises: (a) a means for performing a digital signal nonlinear mapping operation to determine the transitions between adjacent polygons having different optical characteristics; (b) means for performing a Fourier transformation of non-linearly mapped digital signals to obtain two-dimensional nonlinear coordinates corresponding to the direction, position, and intensity of the transitions of said polygons; (c) means for filtering two-dimensional nonlinear coordinates to prevent erroneous data on the direction and positioning of the transitions of said polygon optical properties; (d) means for performing a Fourier transformation of the filtered two-dimensional nonlinear coordinates to restore digital signals corresponding to the representation of the polygon image obtained by the optical reader; (e) means for browsing the converted digital signals to identify the optical properties of each said polygon center and its location within a polygon set; (f) means for decoding said polygons in an inversion of said polygon coding process. 58. An apparatus according to claim 57, wherein the non-linear mapping means is a means of providing a two-dimensional map for transitions between adjacent polygons, as well as between polygons and their separating gaps with different optical characteristics, read by the optical reader calculating the optical characteristics of an image by calculating the standard deviation between each pixel and its adjacent pixels, while the larger standard deviations correspond to the transition zones to the boundaries of said polygons. 59. The apparatus of claim 57, further comprising a means for normalizing, prior to nonlinear mapping, each optical characteristic of the image of the scanned label to a predetermined optimum level. 60. The apparatus of claim 57, further comprising a means for correcting an image scale prior to nonlinear mapping to obtain an image with the same magnification in a horizontal and vertical direction. 61. The apparatus of claim 58, further comprising a means for determining the threshold of each polygon corresponding to the center of each polygon found in step (e) prior to non-linear mapping to determine the corresponding optical properties of said polygons. 62. The apparatus of claim 61, wherein the means for determining the signal thresholds further comprises means for producing histograms corresponding to the optical properties of said polygons. 12 LV 10820 63. The device according to claim 56, 57 or 62, characterized in that the means for browsing the signals includes: (i) an initializing means for detecting the signals of the two-dimensional synchronous reconstruction in a predetermined signal area to determine the location of the greatest brightness to determine the largest signal intensity site; (ii) means for performing a re-browsing cycle, which browses the signals of two-dimensional synchronous reconstruction across the whole of said signals, starting with the highest intensity location determined by the agent (i) and browsing each adjacent major brightness location, thereby identifying the center of each polygon. 64. The apparatus of claim 63, wherein the image scanned by the optical reader comprises a recognition target consisting of a set of concentric rings with different alternately spaced optical features, wherein the device includes means for locating said target by filtering digital signals and comparing said target mark. said digital signals with a pre-selected frequency signal. 65. An apparatus for decoding the flow of digital signals corresponding to a scanned coded partial bonded polygon set scanned by an optical reader, wherein: the polygons have different distances and are arranged so that the geometric centers of the adjacent polygons are located at predetermined two-dimensional grid vertices, and polygons as well as the gaps therein having one of at least two different optical features, characterized in that it comprises: (a) a means for performing two-dimensional synchronous reconstruction of the image to produce a synchronously reconstructed signal; (b) means for utilizing the reconstructed synchronous signal obtained to identify the optical properties of said polygons; (c) means for decoding said polygons in an inversion of said polygon coding process. 66. An apparatus for decoding the flow of digital signals corresponding to a scanned coded partial bonded polygon set scanned by an optical reader, wherein: the polygons have different distances and are arranged so that the adjacent polygonal geometric centers are at predetermined two-dimensional grid vertices, and 13 polygons and the gaps therein having one of at least two different optical features, characterized in that it comprises: (a) a means for performing a digital signal non-linear mapping operation to determine transitions between adjacent polygons having different optical characteristics; (b) means for performing a Fourier transformation of non-linearly mapped digital signals to obtain two-dimensional nonlinear coordinates corresponding to the direction, position, and intensity of the transitions of said polygons; (c) means for filtering two-dimensional nonlinear coordinates to prevent erroneous data on the direction and positioning of the transitions of said polygon optical properties; (d) means for performing a Fourier transformation of the filtered two-dimensional nonlinear coordinates to restore digital signals corresponding to the representation of the polygon image obtained by the optical reader; (e) means for browsing the converted digital signals to identify the optical properties of each said polygon center and its location within a polygon set; (f) means for decoding said polygons in an inversion of said polygon coding process. 67. The apparatus of claim 66, wherein the non-linear mapping means is a means of enabling the creation of a two-dimensional map for transitions between adjacent polygons with different optical characteristics, calculating the optical deviations of the image read by the optical reader between each pixel and adjacent pixels, and the larger standard deviations correspond to transition zones to the boundaries of said polygons. 68. The apparatus of claim 66, further comprising means for normalizing, prior to nonlinear mapping, the optical character of each image of the scanned label to a predetermined optimum level. 69. The apparatus of claim 66, further comprising means for correcting the image scale prior to nonlinear mapping to obtain an image with the same magnification in the horizontal and vertical directions. 70. An apparatus as claimed in claim 67, further comprising a means for determining, prior to the non-linear mapping, the threshold of each polygon center corresponding to the scanned image of the label in step (e) to determine the respective optical properties of said polygon. 14 LV 10820 71. The apparatus of claim 70, wherein the means for determining the signal thresholds further comprises means for producing histograms corresponding to the optical properties of said polygons. 72. An apparatus according to claim 65, 66 or 71, characterized in that the means for browsing the signals includes: (i) an initializing means for browsing the signals of the two-dimensional synchronous reconstruction in a predetermined signal area to determine the largest brightness location to determine the largest signal intensity site; (ii) means for performing a re-browsing cycle, which browses the signals of two-dimensional synchronous reconstruction across the whole of said signals, starting with the highest intensity location determined by the agent (i) and browsing each adjacent major brightness location, thereby identifying the center of each polygon. 73. An apparatus as claimed in claim 72, wherein the image scanned by the optical reader comprises a recognition target consisting of a set of concentric rings with different alternately spaced optical features, the device further comprising means for finding said target by filtering digital signals and comparing said digital signals with a pre-selected frequency signal. 74. A method for encoding information on an optically readable label containing a partially polygonal set, wherein: the polygons have different distances and are arranged so that the adjacent polygonal geometric centers are located at predetermined two-dimensional grid vertices, and polygons, as well as gaps between them characterized by one of at least two different optical features, characterized in that: (a) each polygon is assigned one of at least two optical properties to produce a partially connected polygon set with different optical properties; (b) encode the information by placing polygons in a predetermined sequence; 75. The method of claim 73, further comprising: (a) determining the polygon of each polygon in a dot matrix assigned to it; 15 (b) prints the set of points. 76. A method for encoding information on an optically readable label comprising a set of polygons in which: the polygons have different distances and are arranged so that the geometric centers of adjacent polygons are located at predetermined two-dimensional grid vertices, and the polygons have one of at least two different optical characterized in that: (a) each polygon is assigned one of at least two optical properties to produce a partially connected polygon set with different optical properties; (b) encode the information by placing polygons in a predetermined sequence; 77. The method of claim 76, further comprising: (a) determining the polygon of each polygon in a dot matrix assigned to it; (b) printing said set of points. 78. A method for encoding information in an optically readable label comprising a set of unrelated polygons, wherein: the polygons have different distances and are arranged so that the adjacent polygonal geometric centers are located at predetermined two-dimensional grid vertices, and polygons as well as gaps between them have one of at least two different optical features, characterized in that: (a) each polygon is assigned one of at least two optical properties to produce a set of unrelated polygons having different optical properties; (b) encode the information by placing polygons in a predetermined order, 16 EN 10820 (c) printing each polygon with its specified optical properties. 79. The method of claim 78, further comprising: (a) determining the polygon of each polygon in a dot array assigned to it: (b) printing said set of points. 80. The method of claim 74, 76 or 78, wherein step (b) comprises positioning two or more polygons at predetermined label locations. 81. The method of claim 80, further comprising the step of splitting the encoded information into at least two major and smaller importance categories and encoding the most important and least important information at separate predetermined label locations. 82. The method of claim 81, wherein the information of the highest and lowest importance is supplemented with error detection information. 83. A method as claimed in claim 74, 76 or 78, further comprising encoding the predetermined polygon set with error detection information and locating the coded polygons between the other polygons. 84. The method of claim 82, further comprising the use of error detection information to correct errors in the information read from the label. 85. The method of claim 83, wherein the error detection information may be used to correct errors in the information read from the label. 86. The method of claim 74, 76 or 78, wherein the coding step is arranged to optimize the number of polygons having different optical properties. 87. A method for storing and reading information, characterized in that it comprises the steps of: (a) printing an information coded polygonal set on the label, wherein: the polygons have different distances and are arranged so that the geometric centers of the adjacent polygons are located the predetermined two-dimensional grid vertices and the polygons as well as the gaps between them have one of at least two different optical characteristics; (b) illuminates the label; (c) detecting reflected light from polygons by an optical reader; (d) generating analog electrical signals corresponding to the intensity of the reflected light from said optical characteristics of each reader pixel; (e) converting analog electrical signals into successive digital signals; (f) storing digital signals in a storage device connected to a computer to produce digital signals; (g) decoding the representation of digital signals to obtain the characterization, orientation and intensity of each of said polygons; (h) generating a binary flow of numbers from a computer corresponding to the information contained in the decoded polygons. 88. The method of claim 87, wherein the label further comprises a set of concentric rings in which the rings alternately exhibit one of the two optical features. 89. A method for storing and reading information, characterized in that it comprises the steps of: (a) printing on a label an informatively coded set of unrelated polygons, wherein: the polygons have different distances and are arranged so that the geometric centers of adjacent polygons are located the predetermined two-dimensional grid vertices and the polygons as well as the gaps between them have one of at least two different optical characteristics; (b) illuminates the label; (c) detecting reflected light from polygons by an optical reader; 1820 (d) generates analog electrical signals corresponding to the intensity of the reflected light from said optical characteristics of each of the reader pixels; (e) converting analog electrical signals into successive digital signals; (f) storing digital signals in a storage device connected to a computer to produce digital signals; (g) decoding the representation of digital signals to obtain the characterization, orientation and intensity of each of said polygons; (h) generating a binary flow of numbers from a computer corresponding to the information contained in the decoded polygons. 90. The method of claim 89, wherein the label further comprises a set of concentric rings in which the rings alternately exhibit one of the two optical features. 91. A method for storing and reading information, characterized in that it comprises the steps of: (a) affixing on the label an informative coded set of polygons in which: the polygons have different distances and are arranged so that the geometric centers of adjacent polygons are located the predetermined two-dimensional grid vertices and the polygons as well as the gaps between them have one of at least two different optical characteristics; (b) illuminates the label; (c) detecting reflected light from polygons by an optical reader; (d) generating analog electrical signals corresponding to the intensity of the reflected light from said optical characteristics of each reader pixel; (e) converting analog electrical signals into successive digital signals; (f) storing digital signals in a storage device connected to a computer to produce digital signals; (g) decoding the representation of digital signals to obtain the characterization, orientation and intensity of each of said polygons; 19 (h) generates a binary flow of numbers from a computer corresponding to the information contained in the decoded polygons. 92. The method of claim 91, wherein the label further comprises a set of concentric rings in which the rings alternately exhibit one of the two optical features. 20