CA2116540A1 - Identification system - Google Patents

Abstract

2116540 9307006 PCTABS00021 An identification system involves the labeling and then tracking of grouped items such as logs, shipping containers, or packets of mail and reporting the current location of identified items during transport, processing and storage. Machine readable labels (400, 500) are provided, adapted for recognition and reading from within a cluttered scene. These labels (400, 500) have bordering indicia - used for locating purposes - distinguishable from inner informative indicia. Typical bordering indicia include either a series of small, substantially similar marks like filled or hollow ovals or one circle or part of a circle, or a sequence of locating symbols or characters. Typical informative indicia include dots, bars, rings or regional text characters. Multiple coding methods and spatial (e.g. Latin Square) replication of indicia are used to minimize errors.

Description

WO 93/07006 PCr/US92/08548 '~

211~40 -IDENTIFICATION SYSTEM . ~

! ~ ~
FIELD .

This patent relates to digital image acquisition and subsequent recognition and decoding of machine-readable characters and/or coded indicia printed onto labels to be affixed to, 10 or printed directly onto fixed or 1ransportable objects.

BACKGROUND

Although a number of systems exist for providing one-by-one identi~lcation of data carried on passing objects or identifying locations of objects and then acting on the -information found, (such as at the point of sale in a supermarket) there is still a need for a system capable of coping in one sLngle capture action with a whole aIray of items that have come together at some point - which may be outdoors - in a storage or distribution -- ne~vork. Preferably analysis and repor~ng are also fully integrated into the system.
For example, there is a need for firstly the identification and secondly the convenient and preferably automatic recording of logs and processed timber at various points during transportation, pr~essing, and storage.

It is an object of this invendon to provide an improved automatic identi~lcation and location-tracking system for objects viewed against complex backgrounds, or at least to provide the public with a useful choice. ~ -In one aspect the invention provides a machine-readable label capable of being applied to an item, said label carrying contrasting indicia compatible with machine vision equipment wherein said indicia include at least one distinctive border marking which constitutes an outer border defining the area covered by an adjoining information-35 holding field, and said information-holding field is capable of containing a plurality of information-carrying indicia.

W 0 93/07006 PC~r/US92/08548 2116~0 - 2 - ~` ~

ln another aspect the invention provides a method of identifying one or more items at a site, comprising the steps of:
labeling each of said one or more items with a machine-readable label, said label 5 carrying contrasting indicia compatible with machine vision equipment, wherein said indicia include at least one distinctive border marking which constitutes an outer border -defining the area covered by an adjoining information-holding field, and said information-holding field contains information-carrying indicia relevant to its respectivc item, 10 recording at least one image of at least one labeled itern at the site, converting the at least one image into a computer-compatible form, applying machine vision algorithms to detect the presence and position of each distinctive label border within each image, computing the location of each adjoining information-holding field, assessing the rotational orientation of each label, ~ -detccting and decoding inforrnation-carrying indicia within the label bordcrs, to identify cachitem.
,~
Thc identificadon labcl or syrnbol of this invention and/or the identification method of .. . . .
20 this invendon arc particularly suited to the labeling and tracking of groups of items such as logs. In the preferred embodiments of this invention logs are preferablyinitially idendfied at one or both cnds with a unique label at a stadon, by ownership, locadon, handlcr, typc, or quality. The uniquc label can carry information acting as an index to a data base. The image capnlre stage may be required during loading of a ship.
Other applications includc the locating of items in a warchouse, from small boxes up to shipping containers, or thc idcntification of passing vchicles from a distance or identificadon of fixed bin arcas in a warchouse. On an item-by~item basis the system can bc applicd to mail at sorting stadons where it can also serve to track mail during 30 distribudon. ---Information derived from such a systcm may be used to categorize shipments, to ~ ;
prepare processing stations, or to pinpoint the whereabouts of cach of many items during transport operations or in storage. Accurate identification can aid in efficient 35 operation and production management and can help reduce stock loss.

WO 93/07006 PCI/US92/08~48 ~ ~

2116~40 The following embodiments are given by way of example only and are not intended tobe limiting on the scope of the invention. Many variations or equivalents will be apparent to those skilled in the ar~. ;
s DRAVVINGS

In the description of the drawings, reference will be made to filled black areas such as black circles, ovals, or triangles. However, the blackness is illustrated in the follo ving figures with shading.

Figure 1: This diagram shows a typical arrangement of mobile camera platform, and a bundle of labeled logs, at the ~me of image capture in a dockside environment.

Figure 2 This diagram shows the contents of a single entire captured image, showing a bundle of bunted logs on a stacking cradle. ; ~;

Figure 3: This diagram shows examples of encoded labels with an outer fixed circular frame, about a concentric foIm of barcode mar~ings. The lower label shows an example of a circular barcode label having information corresponding to that of Figure 4 and Figure ~. Each label has an outer black control ring, a middle black control ring, and a ccntral black point. Black and white lines have equal thickness in the preferred coding scheme.

Figure 4: This diagram shows an cncoded label, which contains alphanumeric identification code, duplicated in a partial Latin Square form, with an orientadon- `
providing row of open circles above the information-carrying indicia, and a surrounding f~ne of circular shape.

Figure 5: This diagram shows an example of an alphanumeric encoded label having a frame of open and closed ovals arranged along straight lines which uniquely locate the " outside of the label and specify the orientadon of the label. The identification code within the label consists of nine alphanumeric characters and the code is repeated three times in a partial Latin Square forrn with spatial redundancy so that within any three columns the complete number appears.

wo 93/07006 Pcr/uss2/08s48 ~ --.
2116540 ~4~ ~

Figure 6: This diagram shows an encoded label which contains alphanumeric codeæ ~ -and also a coded pattern of short and long bars incorporating parity bits and spatial i - `
redundancy within individual codes (each code accompanied by a complement of itself 5 alongside) and with an outer frame of a pattern of symbols around both types of codes.
The code is repeated three times in a partial Latin Square form with spatial redundancy -so that within any three columns the complete number appears.
., ~
Figure 7: This diagram shows an example label containing both alphanumeric codes10 and also patterned dots incorporating parity and spatial redundancy within individual codes and with an outer frame of a pattern of symbols around both types of codes.
Each line contains a rotated set of codes so that within any three character columns the complete number appears.

15 This example - as does Pigures 3, 8 and 9 - also provides a conventional bar code holding the same information, with text, outside the border. This is useful where goods may also need to be tracked with a conventional bar code, as read by a hand reader or in other existing ways. It is also useful where an existing bar code system is to be run in paralld, at least during a transition period.
` 20 `
Figure 8: This diagram shows an encoded label which contains both alphanumeric codes and also a coded pattern of short and long bars incorporating parity and spatial redundancy within individual codes (a complement of the code alongside) and with an outer frame of symbols (triangles in both open and closed styles) around both types of 25 codes. The code is repeated three dmes in a Ladn Square form with spadal redundancy so that within any three columns the complete number appears.

Figure 9: This diagram shows an example of an alphanumer~c encoded label which uses a frame of open and closed ovals which uniquely locate the outside of the label and 30 specify the orientadon of the label. The identificadon code within the label consists of eight alphanumeric characters and the code is repeated eight dmes in a complete Latin Square fonn with spatial redundancy so that within any column and most sub-areascontaining 8 characters, the complete idendficadon code appears.

wo 93/07006 Pcr/Vs92/08548 Figure 10: This diagram shows an example of a user-printablc label having a border, a line forming a circle, and an orientation indicium which is shown as a row of open ovals. This is a pre-prlnted label to which information-carrying indicia may be added by 5 the user at the time of use - such as at the time of item classification.

Figure 11: This diagram shows an example of an alphanumeric encoded label without informative indicia; having a frame of open and closed ovals which su~rounds a blank information-carrying space; this is another pre-printed label. This label also bears 10 registration marks to aid in accurate location of indicia.

Figure 12: This example label illustrates a mixture of two codes; one human-readablc and one machine-readable, mixed together within a 3 x 9 modified Latin square replication. The bar-code marking below may be used to (for example) aid in the 15 transition from an older recording method.
....

PREFERRED EMBODIMENTS

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EXAMPLE APPLICATION USING CIRCULAR ENCODED LABELS

In one embodiment circular encoded labels are used in idendfying objects during or after handling, such as the ends of rods, pipes, bottles or logs which have no normal -~
single positional (rotational) orientation.

In this example we prefer to use fixed-width rings as a representation for a number. An outcrmost set of three rings has preferably the radially second of the three shaded in a color contrasting with the other two rings to provide a frame of reference for locadng the circular encoded label within a complex image.

Optionally, additional control rings can be used for error checking purposes. Por example the black border ring (represented by shading) can be an outer control ring, there can be a middle control ring, and a central control point. The software uses these as checks that the symbol has been scanned correctly.

WO 93/07û06 PCI JUS92/08~i48 2116~40 -6-An application for such a circular encoded label is the identification of logs and subsequent automatic recognition of the log by locating the circular frame and reading the circular encoded label.
S ' As each log is documented on arrival at a marshaling yard a seven digit number is assigned to the log. A computer generases copies of a label, perhaps an 18 cm diameter circular black barcode pattern of the number on a sheet of white plastic. Label indicia are as indicated in Figure 3. In this example individual rings are 3 mm wide. The ~0 plas~ic sheets are then stapled preferably to both ends of the appropnate log.

When a grab subsequently picks a load of logs and carries them across to load on a ship or truck for shipment, the grab is routed across a recording area first. The recording area positively forces the grab to move to the scanning position where the grabber is then 15 stopped by blocks. A set of flood lights is then automatically turned on and one end of the set of logs is scanned with all logs in the jaws of ~e grab being scanned at once. At the end of the scan, the lights are turned off and the blocks are removed. The grab then proceeds to deliver the logs to the truck or ship.

20 Alternatively, and as shown in Figures 1 and 2, a mobile recording platform 13 mounted on a vehicle 10 equipped also with flood lights 15, a power source 16, dual cameralrangefinder units 19, and a computer 17 coupled to a control box 14 may be used to approach a bundle of logs 12, 202, previously placed on a cradle 201 by a grab and preferably bunted by a mobilo ram into approximate alignment. The recording `
25 platform captures an image or a composite image 200 of one end, then moves to the other end and captures a second image. The informadon is transmitted by wireless 18 to a remote analysis station.

A typical image holds a content similar to that of Figure 2, though with more 30 background clutter. The image 200 has sufficient resolution to allow decipherment of each label 204 on each item (here logs, 202). A label of the type used in this drawing is reproduced as Figure 4. Preferably the cradle 201 also bears identifying visual or wireless sensing indicia such as bar codes or radio identification tags 203 in order to locate the whereabouts of the items at the time of recording. Note that the preferred 35 pixel density is much finer ~han the squares included in the pattern used to indicate wood at the end of each log. A typical line-scan camera has a 3456-photodiode CCD

wo 93~07006 Pcr/uss2/o8s48 - 21165~0 ,~"
linear array giYing 3456- pixel columns, and preferably 11,200 rows are assembled for one image. A typical area-capture camera has a 4096 x 4096 photodiode CCD array giving 4096 pixel columns and 4096 rows in each captured image taken of a section of S the cradle and assembled into a full picture of the cradle.

The entire scanned image is analyzed by computer to locate all label frames and identify the logs based on the information within each label. In the case of circular barcodes (300,301), the circularity of the encoded label provides redundancy of 10 information by allowing several alternative values to be calculated from analysis of different radial segments. In the case of alphanumeric codes, the indicia representing the code are repeated several times. A Latin Square replication method is preferred, as it is statistically sound. Multiple redundancy provides safeguards against information loss due to degradation of the encoded label due to dirt or other contamination or CCD
15 element failures. Multiple code types provide safeguards against misinterpretation by a single analysis roudne.

The captured image is compressed and transmitted by radio 18 to a remote computer station (not shown) for storage, subsequent analysis, and later viewing. An analysis 20 computer program automatically retrieves the stored image, analyses the image and generates a f~e of decoded idendficadon codes for the image.

According to this invention, pre-printed labels might be supplied with markings as in the example of Figure 10, and on a preferred type of paper material. One such preferred 25 material is a plastics-filled paper with a matt surface, which tolerates the heat applied during toner fusing during laser printing. This label, 1001, has a line forming a circle, and an orientadon indicium 1002 which is the row of open ovals which is intended to lie above the information-carrying indicia.

Alternatively one might use a pre-printed label 1100 in the style of Figure 11 which has compact indicia 1102 as a border. Again, a row of open ovals 1103 serves as an orientation mark. This label also bears registration marks 1101 to aid in accurate location of the information bearing indicia represented by grid 1101.

wo 93/07006 Pcr/uss2f~8s48 21165~0 -8- .~

EXAMPLE APPLICATIONS USING ALPHANUMERIC AND MARK CODES

Figure 4 shows alphanumeric characters (it is the label shown as 204 in Figure 2) inside 5 a circular frame or border 400. While the border itself does not indicate the orientation of the information, a secondary bor~er comprising a row of open ovals above the text does.

The embodiments as shown in Figures 4 tO 9 and 12 employ labels having 10 alphanumeric identification codes and incorporating spatial redundancy. Those of Figures ~, 7, 9 and 12 are each sur~unded by a f~ne comprising a series of open and closed ovals. Figure 6 uses a border composed of characters, and Figure 8 uses open and closed triangular symbols. Our order of preference for frame indicia in terms of computer recognition suitability is ovals, then triangles, then characters. Figure 12 illustrates a label 1200 containing a mu~ture of code types 1201 within a 3 x 9 modified Latin square spatial replicadon.

Any of the labels of Figures 3 to 9 or Figure 12 are suitable for use in identifying objects during or after handling such as, individual or groups of logs, pallets of timber, 20 and individual or stacks of boxes.

The small repetidve characters preferred for our border indicia are easy to recognise by means of machine-vision algorithms scanning a large array systematically, looking for identifiable labels. The series of indicia - or even arcs or a complete circle - are 25 preferable to straight line frames because they define the whereabouts of theaccompanying information more clearly and because they are easier to locate thanslraight lines. Arcs can be located from the analysis of only two rows or columns; lines require more rows and columns and also end-points to disdnguish them from arcs. For instance, single straight lines are hard to locate, are commonly found in image 30 backgrounds, a~d the site of the informadon is still possibly on one side or the other.
Pattern-matching algorithms, for example, can be used to locate disdncdve characters such as these which are chosen at least in part for their relative rarity in the world outside one or more labels. Ovals and more so triangles intrinsically indicate orientatdon.
In the case of this illustrative example, (and in particular for the case of circular coded wo 93/070~6 Pcr/us92/0854X
J
5 4 0 ::
labels as shown in Figure 3) the attached labels 204 are to be differentiated from growth Angs of the logs 202 by ~a) being within a frame of circles of contras~ng color, and (b) having a greater con~st than ~owth Angs have. -~
The encoded alphanumeAc labels 400, 500, 700 and 900 use a row of open circles or ~
ovals, such as the number '0', above a row containing the identification code. 800 uses ~ -triangles. On the ends of the row containing the identification code, a f~e~ shape such as a filled '0' is preferably used as part of the frame. Except for 900, two additional 10 code lines are pAnted below which contain the identification code in rotated spatial order and with the filled circles or ovals on the end. Below the third iden~fication row, a row of filled symbols (part of the frame) is placed to positionally identify the code positions above. For 900, the row of eight identification characters is repeated with spatial rotation seven additional times to produce a complete Latin Square design. For 15 900 a row of filled symbols are placed below the eighth identification line to complete tbe enclosing ~ame.

Alphanumeric characters are selected from a fixed widtb font of European characters and contain character designs which are all easily distinguished from eacb other.
20 Preferably a font in common use in the region (such as Cyrillic or Katakana in corresponding countries) is used as long as it is compatible with machine recognition.
(ln some fonts, some characters differ little from each other, such as the numeral 1, the lower case '1', or zero and the letter "O", and Q, in even a Courier font, which is prefcrred. These may be modified: for example the character represented as octal 370 in 25 the "Postscript" set is a letter "1" with a cross on its stem, or alternatively at least one set of informative indicia printed in at least one different code helps resolve ambiguity).

The characters, of which there are typically nine, are commonly partially or wholly replicated in an m x n Latin Square design as exemplified in Figures 4 through 8 where 30 m = 3 and n = 9 in these instances. In this format the entire code is replicated in the--three horizontal rows below the locating framc, and is also replicated in any group of three columns. (Pigure 9 shows eight characters in an 8 x 8 complete Latin Square design.) l~pically only a single Latin Square generating rule is used for all labels in a single application.
An application for such an alphanumeric encoded label is the identification of logs and WO 93/07006 PCr/US92/08548

2 1 1 G 5 4 0 1 o subsequent automatic recognition of the log by loca~ng the frame of ovals and reading the alphanumeric encoded label. ~ `
. :
S As each log is received at a marshaling yard, a nine character identiflcation is assigned to the log. Upper case and lower case alphabetic characters as well as digits 0 to 9 are used in the identi~lcation code. In our preferred embodiment, a computer generates copies of a spatially balanced pattern of the iden~ification on sheets of white plastic paper, 18 cm by 13 cm, surrounded by an identifying frame of ovals which also iden~fy 10 orientation. Individual alphanumeric characters are 15 mm high and at most 15mm wide in a 15mm wide space. Preferably a second simultaneously readable code represcntation in marks and spaces is also used in the label with spatial rotation to increase the likelihood of corrcct reccgnition in the later computer analysis. Pigure 7 shows such a coded label with an attached bar-code outside the frame to permit 15 simultaneous use of another parallel method. The plastic sheets are affixed preferably to both ends of the log.

The scanned image after capture and transmission (see above -e g. Figure 1) is automadcally analyzed by computer to locate all label frames and identify the logs 20 based on the encoded label value. The frame of ovals (or indeed a circular frame) allows idendficadon and correction of planar skew (i.e. non-perpendicularity of the object planes to the optical axis) in the label image. The frame also allows easy determination of the rotadonal orientation of the image. The additional copies or repetitions of the idendficadon code which are spadally separated allow reconstrucdon 25 of the identification even after two thirds of the label is obscured due to degradadon of the encoded label due to dirt or other contamination, or damage to the label, or due to CCD element, area, column, or row failures.

The captured image is preferably compressed and transmitted by radio to a remote30 computer station for storage, subsequent analysis, and later viewing. An analysis computer program automatically retrieves the stored image, analyses the image and generates a file of decoded identification codes for the image. A typical delay time between the commencement of image capture and completion of analysis can be as short as 33 seconds with commonplace computing equipment. Of course, image 35 transmission may commence as soon as the first of the scanned data becomes available.

w0 93/07006 Pcr/US92/08548 ~

2116S40 :;
SO~TWARE

The following example shows a typical instruction sequence for control instructions for S the log identification when a fixed location scanning station is available.

Control Instruction Sequence:
1. Wait for a grab with logs to arrive at scanning station, and set up camera.

2. Initiatescanandsavescannedimage.

Then, for circular identification codes:

3. Analyze scan image to find all label frarne circles.

4. Idcntify thc ccnter point of a first circle.
(and optionally idendfy other control rings).

. ~ . . . . . . .
2a s. Rcad the code from outside to center at 0 degrees rotadon as sample 1.
.
6. Rcad thc codc from outside to ccnter at 120 dcg~ees rotadon as sample 2.
7. Read thc code from outside to center at 240 degrees rotadon as sasnple 3.

8. Reconcile samples to form idendficadon number. ~ ~ -9. Transmit idendficadon number to database software.

10. Rcpcat stcps 4 to 9 for all other circles in scan.

11. Opdonally, nodfy grab to proceed away from scan~ing stadon.

- :
- - :

wo 93/07006 Pcr/uss2/o8s48 21165~0 -12- `

12. Go back to step 1. ;

Alternatively, for alphanumeric identification codes~

3. Analyze scan image to f~d all label frames. ;

4. Use the frame as recorded to indicate non-perpendicularity and correct it, removing orientation and rotation distortions.
, ~ :

5. Iden~fy the character at each character position in the triple array of characters inside the frame. ;

6. Reconcile the three samples to form an identification.
, ~

7. Transmit iden~fication number to database software. `;

8. Rcpeat steps 4 to 7 for all other f~nes in scan.

.

9. Notify grab to proceed away from scanning station.

10. Go back to step 1.

:.:

EXAMPLE POSTAL APPLICATION US-ING AI,PHANU~qERIC CODES

This preferred embodiment describes mixed alphanumeric and coded postal identification codes for desdnadons incorporadng spatial redundancy and surroundcd "~
30 by a locadng frame. They have been prepared for use in identifying postal letters, packages, boxes, and sacks.
i The encoded labels may use a replicated sequence of letter groups, such as the set 'USPO' as the frame around a row or rows containing the idendficadon code. One 35 such label is shown in Figure 6. Alternatively other types of symbol sequences providing orientation information may be used such as alternating circles and triangles.

wo 93/07006 Pcr/us92/08548 211654~
On the ends of the rows containing the iden~fication code, the frame code sequence is continued as part of the frame pattern. Two additional code lines are belew in Figure 6 - which contain the identification code in a different code rule (such as "ASCII" code in 5 which "mark" here is black and "space" is white or vice versa,) incorporating within-character spadal redundancy, parity eIror coding, and in rotated spadal order and with the continued frame pattern on each end. Alternatively the continued frame pattern on each end may use other symbols such as circles or triangles. Below the third identification row, another sequence of the same let~er groups completes the frame 10 around the idendficadon codes. Alternatively, other symbols may be used below the third row, such as alternating circles and triangles.
: ' Labels may be affixed to objects with any orientation and still be recognized because of the distinctive outer frame which also provides orientation information. Partially 15 obscured labels can still be recognized because of the spatial duplication of the identification within the frame. Defaced labels can still be recognized since both a readable and a differently coded version of the label are used in the same label.

At the time the Ietter, parcel, or box is mailed, a label with frame may be generated by .
20 computer and affixed to the package automatically or manually. Alternatively the frame may be preprinted separately and the identiflcation affixed inside the frame at mailing time. Guidemarlcs such as fine lines or colored bars may be placed inside the frame to aid in alignment of the idendficadon codes within the frame. Figure 10 illustrates one example of an alphanumeric encoded label baving a border according to this invention 25 but with the information field left bla~lc.

Handling is expected to involve separating each item on a moving belt so that only one -item at a ~me passes a scan station. A line scan camera at the scan station is triggered by an object sensor to take a serios of scans of the object as it passes in front of the ` " `
camera. Once past the camera, the area scan image is analyzed by computer to determine the identification code for the destinadon and the code is passed to a sor~ng machine to provide direcdonal routing for the moving item. Unidentified objects produce a dummy desdnadon code intended to route them to postal staff for manual ~ ~-identification. ~-~ ` `

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W0 93/07006 PCr/US92/08548 :::
2 1 1 6 5 4~ - 14~

CODES
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Vehicle licence plates which provide alphanumeric identi~lcation codes incorporating 5 spatial redundancy and surrounded by a locating frame made according to this invention may be used on or directly applied to vehicles such as cars, trains, planes, boats, and to shipping containers to enable automatic scanning and reading of licence identi~cation.

10 In one preferred format as shown in Figure 5, the encoded alphanumeric labels use a row of open circles or ovals, such as the number '0' above a row containing the identification code. On the ends of the row containing the identificadon code, a filled oval or circle, such as a filled '0' is used as part of the frame. I~vo additional code lines are below which contain the identificadon code in rotated spatial order and with the 15 filled circles or ovals on the end. Below the third identification row, a row of filled circles or ovals is placed posidonally as part of the frame identifying the code positions above.

Plates can be manufactured, distributed and affixed in the same manner as previously 20 but with the new codes and su~rounding frame.

A camera or scanner can be used to take pictures of the items in their normal enviromnent and wtomatically Analyze the picture to identify the one or more vehicles in the picture which can be located from the vehicle label frame and which produce 25 eight dot or more wide single color areas at feature edges. The picture may preferably be printed to provide a permanent record with the identificadon, date, and time, along the edge of the print. Opdonally the numbers may be transmitted by radio to a central machine for use in other applicadon such as traffic coundng, stolen vehicle checks, or licence currency checks.
, EXAMPLE MEASUREMENT LABEL APPLICATION USING `
ALPHANUMERIC CODES

35 For commercial goods which require exterior eoding of content details a label, incorporating spatial redundancy and surrounded by a locating frame, may be made for - -` `

wo 93/07~06 Pcr/uss2/08s48 21165~0 use on large containers, pallets of wood, shipping boxes, and other items.

The encoded alphanumeric labels are generated as required and coded with contentS information such as type, weight, quantities, color, destination, date, and other important information. Optionally the framcs may be preprinted.

The encoded alphanumeric labels, which may be any of from Figure 3 to Figure 9 or Figure 12, prefcrably use a row of open circles or ovals, such as the number '0' above a 10 row containing the identification code. On the ends of the row containing theidentification code, a filled circle, such as a filled '0' is used as part of the frame.
Additional code lines are below which contain the identffication code in rotated spatial order and with the filled circles orovals on the end. Bdow the last identification row, a row of filled circles or ovals is placed positionally as part of the frame identifying the 15 codepositionsabove.

At a special checking stadon the goods are to be categorized, wcighed and measured.
Unique labels incorporating the category, weight, measures, date, and idendfication code are automadcally generated at the stadon (optionally onto preprinted frames) and ~. , ~ .. .. . ......... . .
affixed to the item in one or more places. All labels have the same frame. ` -At transit stations and at the final destination cameras or scanners take pictures of hdividual or groups of items. The area scans are then automatically analyzed to locate ~e label frames and automadcally read the information about each item.
: .
The information read from the label may then be directly printed for sorting, classificadon, or handling use. The information may also be stored in the computer for use in other applications such as dispatch load planning, storage planning, new data entry and registration, and arnval notificadon. The informadon may be also used to verify or Analyze computerized records.

VARL~TIONS IN FRAMED LABEL DESIGN `-" ..' -' 35 The encoded label design may be varied in a number of ways depending on the requirements of the pardcular application.

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wo 93/07006 Pcr/us92/08548 21 I 65~ o 16-The total siæ of the encoded label may be increased or decreased to accommodate the material being labeled. Preferably the frame and the number of identification marks or rings are made to vary appropriately to allow for the required number of distinct units to S be differendated in the scanning procedure or to allow the addition of error checking or correcdng informadon as appropriate to the application requirements. ;~

Designs may be scaled up or down as appropriate to maintain the distinguishability of the frame and identification when increasing or decreasing the field of view to take in - s more or less labels in a single image. --~
In addition to rings or characters or ovals or circles of a single color on a common background color, additional colors may be used to provido addidonal distincdveness to the outside frame or to increase the range of distinct values; for examplet using four 15 colors of rings, including the background, allows use of base four numbering for rings.

Frames may be preprinted separately from the identificadon codes and the identification codes printed later. Figure 10 shows an example of a preprinted label carrying just a border according to this invendon comprising a frame of open and closed ovals which . .
surrounds a blank information-carrying space. Information-carrying indicia of any desired fonn may be added by the user at thc dme of use - more particularly at the dme of item classification. ~ `
..
In addition to thc preferred two dimensional aIray, the inforsnation bearing indicia may `~ `
be organized as a one dimensional array of information (preferably using "Latin ~ `
Square" style linear spadal repeddon). ~ ` ``

Preprinted frames may have guidemarks - like crop marlcs - added to aid later ~ `
posidoning of identification codes within the frame.
` ~ :`
ln addition to standard English alphabedc characters, characters from other symbol sets or icons such as Chinese characters, Ratakana characters, or the C;yrillic alphabet, or the or Gothic character set, could be`used for spadal marking codes. ~ ` ~
,.-.
The oval or circular frames around the alphanumeric identification could be coded in `
other patterns of filled and non-filled ovals or circles to provide addidonal information ..

WO 93/07006 P~/US92/08~;48 `) ' 21165~0 such as identification checksums or manufacturer.

Further design variation may be accomplished by using other shapes for the control S frame of the label. For example, a dashed pattern could be used for an outer control ring on a circular code. Another example could be the use of diamond patterns in the frame around the alphanumeric identification.

Multiple partial or complete Latin Square layout rules may be used for the spatial layout of identification codes and be indicated by, for example, use of a special character in the identification code or by the specific frame being used. A Latin Square spatial distribution can also be applied to a replicated linear a~ray of indicia.

Image capture need not be restricted to a camera of the type described. For example one could equip numerous individuals with photographic cameras on stock-taking day to photograph every item in every company warehouse, and later on, scan the images. XY
CCD camera chips of sufficient resolution are becoming more readily available and then a flash illumination system may be pFferred in field data capture situations Image analysis need not be restricted to computers in which information is represented in digital elec~ical form. The principles of optical computers lend themselves to image ` ~`
processing of this type. ~ `

Finally, it should be noted that a number of other variations upon the principles of this invention or other embodiments of i~ still lie within the scope of this invention as set ~ `
forth in the following claims.

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Claims (9)

We claim:

1 A machine-readable label capable of being applied to an item, said label carrying contrasting indicia compatible with machine vision equipment wherein said indicia include at least one distinctive border marking which constitutes an outer border defining the area covered by an adjoining information-holding field, and said information-holding field is capable of containing a plurality of information-carrying indicia

2 A machine-readable label as claimed in claim 1, in which said distinctive border marking is selected from the group comprising at least one arcuate marking, a plurality of alphanumeric characters, a plurality of ovals, a plurality of triangles, a plurality of marks, or any combination thereof.

3 A machine-readable label as claimed in claim 2, wherein said border marking comprises at least one indicia in the form of a border circle, and said information-holding field contains information-carrying indicia comprising a series of concentric circles concentric with said border circle.

4 A machine-readable label as claimed in claim 2, in which said border marking comprises a plurality of indicia forming at least one distinctive sequence arranged into an enclosing shape.

A machine-readable label as claimed in claim 2, further comprising one or more orientation-indicating indicia.

6 A machine-readable label as claimed in claim 5, in which the orientation indicia comprise one or more compact indicia having an appearance distinct from those used in the border.

7 A machine-readable label as claimed in claim 2, wherein said information-holding field contains an array of replicated information-carrying indicia selected from the group comprising alphanumeric characters, distinctive symbols, marks, and multiple code sets.

8 A machine-readable label as claimed in claim 7, wherein said information bearing indicia is replicated within the array in the form of an at least partial Latin Square.

9 A method of identifying one or more items at a site, comprising the steps of:
labeling each of said one or more items with a machine-readable label, said label carrying contrasting indicia compatible with machine vision equipment, wherein said indicia include at least one distinctive border marking which constitutes an outer border defining the area covered by an adjoining information-holding field, and said information-holding field contains information-carrying indicia relevant to its respective item, recording at least one image of at least one labeled item at the site, converting the at least one image into a computer-compatible form, applying machine vision algorithms to detect the presence and position of each distinctive label border within each image, computing the location of each adjoining information-holding field, assessing the rotational orientation of each label, detecting and decoding information-carrying indicia within the label borders, to identify each item.

A method of identifying one or more items, as claimed in claim 9 further wherein said information-holding field of each label contains an array of information-carrying indicia which is replicated in the form of an at least partial Latin Square, and using the replicated information to verify and, if required, to correct the decoded information from the information-holding field.