CA2375577C - Optoelectronic document reader for reading uv / ir visible indicia - Google Patents

Optoelectronic document reader for reading uv / ir visible indicia Download PDF

Info

Publication number
CA2375577C
CA2375577C CA 2375577 CA2375577A CA2375577C CA 2375577 C CA2375577 C CA 2375577C CA 2375577 CA2375577 CA 2375577 CA 2375577 A CA2375577 A CA 2375577A CA 2375577 C CA2375577 C CA 2375577C
Authority
CA
Canada
Prior art keywords
document
indicia
light
light sources
visible
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CA 2375577
Other languages
French (fr)
Other versions
CA2375577A1 (en
Inventor
Sivasamy Premjeyanth
Michael Robert Balderston
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Canadian Bank Note Co Ltd
Original Assignee
Canadian Bank Note Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Canadian Bank Note Co Ltd filed Critical Canadian Bank Note Co Ltd
Priority to CA 2375577 priority Critical patent/CA2375577C/en
Publication of CA2375577A1 publication Critical patent/CA2375577A1/en
Application granted granted Critical
Publication of CA2375577C publication Critical patent/CA2375577C/en
Application status is Active legal-status Critical
Anticipated expiration legal-status Critical

Links

Classifications

    • GPHYSICS
    • G06COMPUTING; CALCULATING; COUNTING
    • G06KRECOGNITION OF DATA; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K7/00Methods or arrangements for sensing record carriers, e.g. for reading patterns
    • G06K7/10Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
    • G06K7/10544Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation by scanning of the records by radiation in the optical part of the electromagnetic spectrum
    • G06K7/10712Fixed beam scanning
    • G06K7/10722Photodetector array or CCD scanning
    • G06K7/10732Light sources
    • GPHYSICS
    • G06COMPUTING; CALCULATING; COUNTING
    • G06KRECOGNITION OF DATA; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K19/00Record carriers for use with machines and with at least a part designed to carry digital markings
    • G06K19/06Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
    • G06K19/06009Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code with optically detectable marking
    • G06K19/06037Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code with optically detectable marking multi-dimensional coding
    • GPHYSICS
    • G06COMPUTING; CALCULATING; COUNTING
    • G06KRECOGNITION OF DATA; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K7/00Methods or arrangements for sensing record carriers, e.g. for reading patterns
    • G06K7/10Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
    • G06K7/12Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation using a selected wavelength, e.g. to sense red marks and ignore blue marks
    • GPHYSICS
    • G06COMPUTING; CALCULATING; COUNTING
    • G06KRECOGNITION OF DATA; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K9/00Methods or arrangements for reading or recognising printed or written characters or for recognising patterns, e.g. fingerprints
    • G06K9/20Image acquisition
    • G06K9/2018Identifying/ignoring parts by sensing at different wavelengths

Abstract

A document reader for optoelectronically illuminating, reading and interpreting (i.e. processing and analysing) indicia appearing on a document in a machine readable zone thereof, wherein the indicia is made visible only under illumination by non- visible light (i.e. UV or IR). UV (or IR) light sources (LED's) of the reader are rapidly switched to a stable, peak UV (or IR) illumination frequency or frequency range to illuminate and render visible such covert UV-visible (or IR-visible) indicia. An optoelectronic image sensor (CCD) captures the document image, which includes the indicia rendered visible by the UV source illumination, and the covert indicia is identified from the captured image. An optical path, being folded by two mirrors so as to provide a compact geometry for the reader, extends between a reading surface on which the document is place and the image sensor. A lens configured for focussing light defining an image onto the sensor is provided in the optical path. The reader may also include bank(s) (array(s)) of visible light sources (LED's), for illuminating visible indicia, in addition to UV and IR LED arrays and any IR light sources may also be used for illuminating visible OCR characters according to ISO 1831. A controller is provided to sequentially activate each different light source bank.

Description

s OPTOELECTRONIC DOCUMENT READER FOR READING UV I IR VISIBLE INDICIA
Field of the Invention This invention relates generally to the field of security equipment and, more particularly, to an optoelectronic document reader for reading matter which is visible only 1 o in the presence of illumination outside of the visible light spectrum i.e.
ultraviolet (UV) or infrared (1R) light, such matter being in the form of text, images or other indicia printed onto a document or surface-visible matter embedded within a substrate of a document.
Background of the Invention 15 Some known methods for improving the security of a document, such as a passport or other identity document, utilize materials which are visible only in the presence of ultraviolet (UV) light. Such materials have been added to certain inks used for security printing to print UV-visible indicia onto a document, whereby the average person viewing such document would be unaware that such indicia is present on the document but a

2 o knowledgeable person (e.g. a customs officer) would inspect such document under UV
illumination to identify such indicia for purposes of assessing the authenticity of the document. The known devices used in the identification of such covert UV
printed indicia comprise UV fluorescent tubes which emit UV illumination. In use, a document to be inspected is placed under the UV illumination emitted by such a device so that any covert 2 s UV-visible indicia on the document is caused to fluoresce with a visible light (i.e. is made visible to an inspector's eye). Disadvantageously, however, such devices are passive only, in that they simply serve to illuminate a specific area; they are themselves unable to read (i.e. via an automated process so as to interpret) invisible indicia which has been printed by means of a UV fluorescent ink. Instead, a user of such known devices is required to manually view and personally interpret the resulting image in order to determine whether the document comprises any covert indicia. Moreover, UV fluorescent tubes have a lengthy stabilization time and, therefore, they are unable to accommodate any high speed 1 o processing application such as would be required by an automated device for reading UV-ink printed indicia. Moreover, such tubes are inherently unstable (and, thus, unreliable) because the peak wavelength of the illumination they produce typically varies over time.
There is a need, therefore, for a document reader which operates on an automated basis for relatively high speed processing of security documents having matter associated therewith which is visible only when illuminated by UV or IR light. Further, there is a need for a document reader which is able to read such covert UV-ink (or IR-ink) printed indicia on a full-page basis. There is also a need for such a reader which is able to illuminate one or more predetermined surface areas of a document with light whose frequency or 2o frequency band is/are within one of the infrared, visible and ultraviolet light frequency bands, depending on the particular indicia on such areas of the document which is to be read, and to switch rapidly from one such frequency or band to another. Still further, there is a need for a document reader which is able to automatically read and interpret such indicia. Moreover, there is a need for such a document reader comprised of solid state components enabling a reduction or elimination of moving parts.

Summary of the Invention In accordance with the invention there is provided an optoelectronic document reader and method for automated reading of first indicia in a machine readable zone of a document, the first indicia being invisible when illuminated with visible light and visible 1 o when illuminated with invisible light of a predetermined frequency range.
A reading surface is provided for placement of a document comprising the machine readable zone to be read by the reader. A plurality of first light sources are spaced apart from the reading surface and configured for illuminating the machine readable zone of a document on the reading surface with invisible Light of the predetermined frequency range (e.g. UV
fight having a peak wavelength of 370nm) when the first light sources are activated so as to cause the first indicia to become visible. An image sensor is configured for capturing an image defined by light focussed thereon and producing electronic data representative of the captured image. An optical path extends between the reading surface and the image sensor and comprises a lens configured for focussing light defining an image onto the 2 o sensor. A document image comprising the first indicia defined by light emitted and/or reflected by the machine readable zone of the document on the reading surface when the first light sources are activated, is transported to the sensor via the optical path and captured by the sensor. A document controller is configured for identifying the indicia from the captured image and outputting the identified indicia for display andlor processing;

- 3 -The first light sources may be UV LED's configured for emitting light of a predetermined ultraviolet frequency range whereby the first indicia comprises UV
fluorescent matter configured for emitting visible light when illuminated by the light of the predetermined ultraviolet frequency range. Preferably, the optical path is folded by a plurality of reflecting surfaces within the optical path.
The document reader is also preferably configured for automated reading of second indicia in the machine readable zone, the second indicia being visible when illuminated with visible light. A plurality of second light sources (e.g. visible LED's) are spaced apart from the reading surface and configured for illuminating the machine readable zone with visible light (e.g. having a peak wavelength of 650nm) when activated. Upon activation of the second light sources the document image comprises the second indicia defined by light emitted andlor reflected by the machine readable zone. In addition, the document reader is preferably further configured for automated reading of third indicia in the machine readable zone, the third indicia comprising characters configured according to OCR
2 o standards specification. A plurality of third light sources (e.g. 1R
LED's) are spaced apart from the reading surface and configured for illuminating the machine readable zone with light of a predetermined infrared frequency range according to the OCR
standards specification when the third light sources are activated. Upon activation of the third light sources the document image comprises the third indicia defined by light emitted and/or 2 s reflected by the machine readable zone.

- 4 -A controller configured for controlling activation of the light sources (e.g.
on a sequential basis in the order of IR, visible and UV), an optical filter positioned within the optical path between the lens and image sensor, the optical filter configured for removing reflected light of the first light sources, and a document controller configured for identifying the indicia from the captured image and outputting the identified indicia for display and/or 1 o processing may be provided.
The light sources are arranged in such a manner that a first bank comprises the first fight sources, a second bank comprises the second light sources and a third bank comprises the third light sources, the light sources of each the bank being arranged to provide uniform illumination of the machine readable zone. In addition, the illumination produced by each bank of light sources is of comparable intensity to avoid saturation of the image sensor.
Description of the Drawings 2 o The present invention is described in detail below with reference to a preferred embodiment and the following drawings pertaining thereto in which like reference numerals refer throughout to like elements.

- 5 -s Figures 1 (a) and 1 (b) are schematic diagrams illustrating the optical principles of operation, and the optical paths, respectively, of a document reader in accordance with the invention;
Figure 2 is a schematic diagram of a plan view of an illustrative document as s o contemplated for use with a document reader in accordance with the invention, this illustrative document comprising five distinct fields (areas) on which different types of identification indicia are printed using an ink which is visible only under illumination outside of the visible light spectrum;
15 Figure 3 is a schematic diagram illustrating the relative numbers of IR, visible and UV LED's used in a preferred embodiment of a document reader according to the invention;
Figure 4 is a schematic block diagram showing the components of a preferred 2o embodiment of a document reader according to the invention; and, Figure 5 is a flow chart showing the steps performed by exemplary software run on the document reader of Figure 4.
2 s Detailed Descrilotion of a Preferred Embodiment

- 6 -s Figure 1 of the drawings illustrates the optical principles of operation which are applied by a preferred embodiment of a document reader in accordance with the invention.
A document 10 is illuminated, on a controlled and rapid basis, with light emitted from an array of light sources 35 comprising banks of three different types of LED's, namely, IR
LED's which emit light in the infrared frequency band, visible LED's which emit light in the to visible frequency band (the visible spectrum) and UV LED's which emit light in the ultraviolet frequency band. The different types of LED's (i.e. 1R, visible and UV) are illuminated on a sequenced basis in the preferred embodiment whereby the LED's are illuminated sequentially according to the type of LED, for example in the order of IR
illumination first, visible illumination second and UV illumination third.
Optionally, the user 1 s may select a frequency or category of frequency (e.g. UV) to correspond to one of the LED
types used in order to rapidly illuminate and read a specific image of interest.
Many security documents, such as machine readable travel documents (MRTD's), contain printed information which must conform to both the International Standards 2 o Organization ISO 1831 standard governing the reading of characters by means of an optical character recognition (OCR) specification as well as the specification for travel documents set by International Civil Aviation Organization ICAO (document 9303, paragraph 7.2.1) requiring that such characters be visible. As defined in ISO
1831, any security feature appearing in the machine readable zone (MRZ) of a document is not to 2s interfere with accurate reading of any OGR characters at the B900 range i.e. in the near infrared (900t50nm) portion of the spectrum.

Optionally, the IR LED bank may be used for either or both of two purposes, one being for character reading according to the OCR standard noted above, and a second being for illuminating a covert IR-visible indicia so as to render such indicia visible and, thus, readable. In such an embodiment, covert indicia would be printed onto the document using a material (i.e. ink) which fluoresces under IR illumination of the frequency emitted to by the IR LED's. In this manner, such covert IR-visible indicia would function in the same manner as the covert UV-visible indicia of the embodiment described herein.
A transparent window (not shown) provides a reading surface for placement of the document 10 and a protective housing surface for the reader, the window being located between the document and the optical components of the reader shown in Figure 1.
The LED-emitted light waves provide a uniform (i.e. even) illumination of the whole machine readable zone (MRZ) of the document which is to be read under such illumination and this allows the document to be read quickly, on a page-by-page basis. The light 2 o waves emitted by and/or reflected from the document 10 are transmitted to and reflected by a lower mirror 20 to an upper mirror 25 where they are reflected downwards, first through a lens 30, which collects and focuses photons of the document-emitted/reflected light waves, then through an optical filter 32, and then onto an optoelectronic image sensor 40.
_ g _ s As shown, the optical characteristics and mechanical positioning of the lens 30 and mirrors 20, 25 are chosen so that the entire MRZ (being up to 120mm x 80mm in the embodiment described herein) is focussed onto the optoelectronic image sensor 40 (being 6.91 mm x 4.6 mm in the embodiment described herein) without incurring significant distortion and so that the longer optical path folds into a compact arrangement inside the 1 o reader.
The printed fluorescing matter on the document 10 which is excited by the UV
LED
illumination emits a broader frequency spectrum of light waves than is required to produce a sharp image on the sensor 40 and the optical filter 32 (which has a cut-off wavelength 1 s at 420nm) reduces that broad spectrum. The optical filter 32 does not affect the visible or near-IR light but does eliminate the reflected, unwanted UV electromagnetic waves (to which the CCD image sensor is sensitive and which can make the image appear too light and hazy), and some visible light waves in the violet frequency band so that such light waves do not reach the image sensor 40. Advantageously, the elimination of unwanted 2 o UV spectrum components improves the visible and near-IR band images.
The image sensor 40 selected for use in the document reader described herein is a CCD (charge coupled device), specifically a sensor sold underthe product identifier KAF-401 E manufactured or supplied by Eastman Kodak Company of the U.S.. Other sensors 2 s which may suitable for use in a different embodiment include a CMOS
sensor, such as that provided by Kodak under product identifier KAC-1310, and a CIS (Contact Image Sensor).

s A MRZ (viewing area) of 120mm x 80mm (see the area 50 of the document 10 shown in Figure 2) is captured by the image sensor 40 for extraction of a particular feature, such as a portable data file (PDF) image, a visible image such as a photograph, OCR text, UV printed matter, etc., and the extracted feature, and optionally the captured image also, are transmitted by the sensor 40 to a host computer by means of an RS-232 port, a parallel 1 o port or an Ethernet interface device. Advantageously, the CCD 40 and associated hardware captures the image in the form of digital data having a resolution of 768 pixels x 512 pixels for this viewing area (if desired, a higher resolution can be obtained by selecting a different sensor).
1 s The optical path of the reader is shown by Figure 1 (b). The geometry of the optical path is dependent upon the magnification (being 0.058 in the embodiment described herein), the field of view (FOB and the focal length (being 10.3mm in the embodiment described herein) of the lens 30. The two mirrors 20, 25 shown by Figures 1 (a) and 1 (b) are used to fold the path and thereby minimize its size so as to fit into the compact reader.
2 o The F-number of the lens (selected to be 2.8 for the embodiment of the described embodiment) is selected on the basis of the illumination, depth of focus, diffraction and abberation effects.
Previously, it was thought by persons skilled in the art that a high resolution 2 s automated imaging reader according to that of the present invention could not be made operative due to the effects of chromatic aberration when using multiple spectral bands - to -and the foregoing performance deficiencies associated with the UV light tubes.
Visible/invisible light LED devices which emit peak frequencies extending close to or below the visible spectrum have become known for use in laser technologies.
Surprisingly, the applicants have determined that an array of similar solid state LED devices, configured to emit UV light, may be used successfully and advantageously in a document reader to 1 o achieve automated UV image reading.
The applicants have found that use of an appropriate UV fluorescent printing material together with an appropriate UV illumination, combined with use of a lens 30 having a sufficient depth of focus, reduces the effects of such chromatic abberation to a level which is acceptable. In addition, since the UV fluorescent material of the document acts a light source under UV illumination, unlike visible printed characters/images which absorb light, for purposes of accuracy on reading the UV ink printed matter, it is necessary that the document substrate, as well as any protective covering placed over the document, be UV dead (meaning that it should not contain superfluous UV excitable matter which 2 o would interfere with the correct image to be read) and that the background area of the UV
ink printed areas be absorbing (i.e. dark) and non-interfering. Additionally, it is necessary to avoid saturating the image sensor. This is avoided by ensuring that the intensities of the light emitted/reflected by the document on illuminating the different LED
banks are matched (i.e. by appropriately controlling the activation levels of the LED's).

The use of UV LED's (as compared to tubes) enables the exposure time for UV
illumination to be closely controlled and rapidly switched. Specifically, when using an LED
having a stabilization time of 50 nanoseconds, UV illumination may be switched on and off within a few milliseconds. The choice of UV light frequency to be used for illuminating the document is dependent upon the UV LED to be selected and, this, in turn, is dependent to upon the exciting material of the ink or substrate which is used as the hidden security material to be read by the reader. For the preferred embodiment, UV LEDs supplied and/or manufactured by Nichia Corporation, under the product identifier NSHU550E, were selected for use in the UV light source array. This UV LED product emits a narrow band illumination having a peak wavelength at 370nm and provides a short stabilization time (i.e.
the time needed from activation to achieve peak wavelength illumination) of 50ns. This UV
LED also has built into it a Zener Diode providing protection against electrostatic discharge (ESD). The applicants have found that selection of a UV fluorescent printing ink which, when excited by a predetermined UV frequency light (i.e. of wavelength 370nm in the preferred embodiment), emits an appropriate frequency (i.e. in the preferred embodiment 2 o being a blue light of approximate wavelength 423nm) of visible light, combined with use of a lens 30 having sufficient depth of focus and less chromatic aberration to reduce chromatic aberration effects to a level which is acceptable with the use of software as described herein, results in a capturing of a usable image of the UV-ink printed indicia.
Undesirably, some unwanted light frequencies are caused to be reflected onto the lens 30.
To block these unwanted UV light frequencies an optical filter 32 is included in the optical path prior to the sensor 40, the filter 32 being a high pass UV filter having a cut-off at , e..w.~~", ~..,Inl~~.l.,r,~ I.

420nm (supplied and/or manufactured by Edmund Industrial Optics under the product identifier GG420).
UV fluorescent inks are well-known in the art and one skilled in the art will be readily able to make an appropriate selection of a UV fluorescent ink for use for printing the covert matter onto the document for any given application. For example, for a thermal transfer printing application the ink described in U.S. Patent No. 6,155,168 assigned to Alps Electric Co., Ltd. of Tokyo, Japan may be selected for use. A further source of suitable UV
fluorescent inks is Angstrom Technologies Inc. of Kentucky, U.S.A. For laser printing applications, a suitable UV fluorescent electrostatic toner is available from this company.
The document reader is able to detect and process different types of covert matter including different types of hidden images printed with UV fluorescent ink, including machine-readable character lines of text, two dimensional barcodes and security device images such as those produced by the assignee of this application, referred to a Pixelplex images, using overlaid deflection and encrypted images, based on a source image (as described in detail in said assignee's PCT Application No. WO 01/80512, published on 25 October, 2001, and republished on 14 August, 2003).

s Optionally, the optical path may include an electrostatic mirror (not shown in Figure 1 ) with reflection and transparent states to authenticate optically variable devices applied to the document such as holograms or kinegrams.
Figure 2 of the drawings shows a plan view of a sample layout of a document 1 o namely, the identification page of a passport, whereby five independent security fields comprising UV fluorescent material are provided. Fields 1 and 3 each comprise machine readable text (alpha-numeric characters) printed with a suitable fluorochrome material which fluoresces when illuminated by a predetermined UV frequency corresponding to the frequency band of the selected UV LED's. The UV-illuminated text images are detected 15 by the image sensor 40 and then interpreted using a conventional OCR-B text algorithm (such algorithms being well-known to persons skilled in the art and readily available in the marketplace). Preferably, to increase the security provided by these fields, the text is scrambled and encrypted using an appropriate software algorithm (such algorithms being readily available in the marketplace). In the preferred embodiment the contents of Field 2 0 3 is numbers corresponding to the passport number such that this field is used as a cross-check against a visibly printed passport number appearing on the document.
Field 2 of the sample document shown in Figure 2 comprises encoded indicia which represents text, the text having been encoded using deflection images so that it appears, 2 s in UV fluorescent material, as a series of vertical lines. This indicia is also detected by the image sensor 40 and interpreted (i.e. decoded) by suitable software in the reader.

Field 4 comprises a two dimensional barcode in the form of a portable data file (PDF) 417 image which is printed in UV fluorescent material. As is well-known by persons skilled in the art, the two dimensional barcode image may comprise any combination of images) and alphanumeric text as permitted by the particular resolution used.
The PDF
image is detected by the image sensor 40 and interpreted by suitable software in the 1 o reader. Optionally, the barcode is broken up into several pieces and those pieces are distributed over the document page in a predetermined manner (being information which is known or learned by the reader's software systems). Since none of the barcode is visible to the user under ordinary light the fact that the barcode is fragmented does not affect the user. It does, however, provide another security feature to the document since 1 s the specific arrangement of the fragments read by the reader must coincide with the predetermined arrangement known by the reader. If the barcode fragment arrangement read by the reader is found not to correspond to the known arrangement, the reader identifies the document as having failed the authentication assessment process performed by it.
Field 5 comprises a security device Pixelplex image printed in UV fluorescent material. As shown in Figure 2, the encrypted source image represented by the covert Pixelplex image is preferably the passport holder's photograph as it appears on the identification page at the time the passport is issued to the authorized holder, whereby the 2 s photograph of the passport holder is revealed upon decryption of the Pixelplex image.

A further security feature (not shown on Figure 2) is provided by the substrate material of the document page and is not limited to any of Fields 1-5, namely, a random distribution of UV-fluorescent pulp fibres within the sheet of paper which comprises the document page. It is known that a small number of such fibres are introduced during the normal manufacturing security papers and that their resulting location within the finished 1 o paper substrate is randomly determined. The random nature of these fibres is used to advantage to provide security by identifying their location on the page at the time the document is created or issued and associating those specific locations with that particular document. The document reader detects and reads these fibres, including their location on the page, and compares this information with the known information pertaining to the fibre locations at the time of the creation or issuance of the document. If the two sets of information do not coincide the reader identifies the document as having failed the authentication assessment process.
Figure 3 of the drawings illustrates the arrangement of LED banks 35 in the 2 o preferred embodiment of the document reader. The LED's are mounted on a substrate 36 in the form of a strip of thermoplastic material having two mounting tabs 34 for installation within and across the reader as shown in Figures 1 (a) and (b). The pattern (arrangement) of LED's in each LED bank is configured to provide sufficient and uniform illumination to the document 10 taking into account the following factors: (i) the directivity (viewing angle) of the LED's; (ii) non-linear human visual perception of image (i.e. unit changes in luminance do not correspond to unit changes in visual sensitivity); (iii) the dynamic range s of the image sensor (CCD), to avoid saturation; (iv) the varying response of the image sensor (CCD) to wavelength changes in that the sensor's quantum efficiency (QE) is higher at red and lower at blue; and (v) required compactness to fit onto the substrate. As shown by Figure 3, the UV LED's 37 are laterally distributed over the substrate with a greater number of the UV LED's 37 positioned towards each end of the substrate 36.
Similarly, to near-IR LED's 38 and visible LED's 39 are laterally distributed over the substrate 36 with a higher concentration of each occurring at the ends of the substrate 36.
The three banks (sets) of LED's are activated in sequence for a period of time 15 determined on the basis of the brightness of the printing material (i.e.
the ink), this activation period typically being between 10 milliseconds and 2 seconds. For a normal operating mode of the preferred embodiment the preferred sequence order for activating the LED banks is !R LED's, visible LED's and then UV LED's. The near-IR LED's emit light at a peak frequency within the range of 900t50nm to meet the ISO 1831 standard.
a o The visible LED's emit light within the range 400nm-660nm and the UV LED's emit light within the range 360nm-380nm, and having a peak frequency at 650nm and 370nm, respectively. However, any or all of the LED's may be activated at a given time, for a given application, in order to illuminate the particular printed images) of interest to the user. For example, the IR LED's may be activated when it is desired to read text printed on the 2 s document using optical character recognition processing in accordance with the ISO 1831 standard. Likewise, the visible LED's may be activated to illuminate the visibly printed s subject matter on the page being read by the reader and/or the UV LED's may be activated to illuminate the images printed with UV fluorescent ink. The illuminated images are focussed onto the image sensor 40 and interpreted by the host computer's software systems to produce a display of the result (i.e. of the read image) for the user.
z. o Figure 4 shows, in block diagram form, the components of the preferred document reader and their interaction. The image sensor 40, being a CCD in the preferred embodiment, captures the image which is visible under the applied illumination in the form of digital data which is transferred to an image Random Access Memory (RAM) 45. Flash memory chips 47 are provided to store firmware and configuration data. A
Digital Signal 15 Processor (DSP) performs processing functions on the digitized image information, the DSP selected for use in the preferred embodiment being supplied by Texas Instruments under product identifier TMS320C32. A reader controller 60, in the form of a field-programmable Gate Array (FPGA) logic chip, is used in the preferred embodiment to perform various controller functions as shown by Figure 4, including the transfer of data 2 o from the CCD 40 to the image RAM 45, controlling the data bus between the DSP 110 and the image RAM 45, controlling the peripheral interface (including controlling the LED arrays 35) and image enhancement. The resulting document image is transferred to a host computer (not illustrated) by means of a serial, parallel or Ethernet interface 70.
2 s A document detector 80 detects the presence of a document 10 on the reading surface of the reader using a combination of photodetector and IR sensor circuits. User - m -s Interface LED's (U1 LED's) 90 are provided to show the status of operations.
The LED's of the LED array banks 35 are solid state devices which are rapidly controllable by software running on the document reader. A magnetic reader 100, able to read up to four tracks of data, is also provided to read data contained on magnetic strip applied to the document, if any.
Figure 5 is a flow chart showing the steps performed by document controller firmware run by the document reader. The document controller software controls the activities performed by the document reader and, in doing so, it determines which software components are run in order to process input an produce the required output.
As such, the functionality of the document reader is limited to documents which have a configuration falling within the scope of the controller software (i.e. to those which can be processed thereby) and, thus, the document reader is effectively matched to a predetermined type of document.
2 o When the presence of a document is detected by the document detector 80 of the reader, the document is scanned by exciting the IR, visible and UV LED bank so as to illuminate the MRZ with one or more of visible, IR and UV illumination, respectively. As stated above, these differing illumination frequency LED banks are normally excited on a sequential basis but can be excited on a directed (individual) basis as desired. For each 2 s scanned (i.e. visible) image appearing in the MRZ of the document as a result of the applied illumination, the image is captured by the image sensor (i.e. the CCD
40 in Figure 4) of the reader and forwarded to a host computer for processing by one or more applications running on the host computer (as desired). A feature locator component of the document controller software locates and identifies the individual features (indicia) of the document image. Specifically, with reference to Figure 2, it locates and identifies the following indicia of the machine readable zone of the document: the visible photograph 51;
to the barcode 52; the OCR text 53, 54; and, the UV visible fields 1-4.
Different types of features are processed differently by individual software components configured appropriately to take the desired processing steps. An OCR
software component 120 processes the OCR features 53, 54 according to conventional 15 processing steps whereby the lines of OCR-B characters of these features are recognized and interpreted. As is known to persons skilled in the art, the OCR software component preferably includes processing steps for context and format checking to determine possible errors in the identified characters. The OCR software component 120 outputs the interpreted character set determined by it and this output is forwarded to a host computer 2 o for display on a monitor and/or further processing as desired. Optionally, the output characters could instead be directly forwarded to an electronic display (such as, for example, if associated processing by other software applications is not desired).
A PDF software component 130 isolates, analyses and decodes the PDF417 2 s barcode feature 52. A UV field software component 140 determines the images of the UV
fields 1-5 and, where applicable, processes these images using the foregoing OCR and s PDF software components. A magnetic card reader software component is also preferably provided for processing data read by a magnetic card reader 100 of the reader.
As for the output of the OCR component, the outputs of each of these software components is forwarded to the host computer for further processing and/or display on a monitor.
1 o The individual optoelectronic system and software processing functions utilised in the foregoing described embodiment are well understood by those skilled in the art. 1t is to be understood by a person skilled in the field of optoelectronics and image processing that a variety of other implementations may be devised for substitution and such persons are expected to be able to apply the present invention to implement various applications 1 s of the same.
Consequently, it is to be understood that the particular embodiment described herein by way of illustration is not intended to limit the scope of the invention claimed by the inventors which is defined by the appended claims.

Claims (20)

WHAT IS CLAIMED IS:
1. An optoelectronic document reader for automated reading of first indicia in a machine readable zone of a document, said first indicia being invisible when illuminated with visible light and visible when illuminated with invisible light, said reader comprising:
(a) a reading surface for placement of a document comprising said machine readable zone to be read by said reader;
(b) a plurality of UV LED first light sources spaced apart from said reading surface and configured for illuminating said machine readable zone of a document on said reading surface with invisible light of a predetermined ultraviolet frequency range when said first light sources are activated so as to cause said first indicia to become visible, said first indicia comprising UV
fluorescent matter configured for emitting visible light when illuminated by said invisible light of said predetermined ultraviolet frequency range;
(c) an image sensor configured for capturing an image defined by light focussed thereon and producing electronic data representative of said captured image;
(d) an optical path extending between said reading surface and said image sensor and comprising a lens configured for focussing light defining an image onto said sensor;
(e) an optical filter within said optical path and configured for removing reflected light of said first light sources; and, (f) a document controller configured for identifying said indicia from said captured image and outputting said identified indicia for display and/or processing;
wherein a document image comprising said first indicia, defined by light emitted and/or reflected by said machine readable zone of said document on said reading surface when said first light sources are activated, is transported to said sensor via said optical path and captured by said sensor.
2. An optoelectronic document reader according to claim 1 wherein said optical filter is positioned between said lens and said image sensor.
3. An optoelectronic document reader according to claim 1 wherein said optical path is folded by a plurality of reflecting surfaces within said optical path.
4. An optoelectronic document reader according to claim 2 wherein said optical path is folded by a plurality of reflecting surfaces within said optical path.
5. An optoelectronic document reader according to claim 3 and further configured for automated reading of second indicia in said machine readable zone, said second indicia being visible when illuminated with visible light, said reader further comprising a plurality of second light sources spaced apart from said reading surface and configured for illuminating said machine readable zone with visible light when said second light sources are activated, wherein upon activation of said second light sources said document image comprises said second indicia defined by light emitted and/or reflected by said machine readable zone.
6. An optoelectronic document reader according to claim 5 and further configured for automated reading of third indicia in said machine readable zone, said third indicia comprising characters configured according to OCR standards specification, said reader further comprising a plurality of third light sources spaced apart from said reading surface and configured for illuminating said machine readable zone with light of a predetermined infrared frequency range according to said OCR standards specification when said third light sources are activated, wherein upon activation of said third light sources said document image comprises said third indicia defined by light emitted and/or reflected by said machine readable zone.
7. An optoelectronic document reader according to claim 5 wherein said second light sources are visible LED's.
8. An optoelectronic document reader according to claim 7 wherein said third light sources are IR LED's.
9. An optoelectronic document reader according to claim 8, and further comprising a controller configured for controlling activation of said first, second and third light sources.
10. An optoelectronic document reader according to claim 9 wherein said controller is configured for activating said first, second and third light sources in a sequential manner.
11. An optoelectronic document reader according to claim 10 wherein said light sources are activated in the order of said third light sources, said second light sources and said first light sources.
12. An optoelectronic document reader according to claim 10 wherein said light sources are arranged in such a manner that a first bank comprises said first light sources, a second bank comprises said second light sources and a third bank comprises said third light sources, said light sources of each said bank being arranged to provide uniform illumination of said machine readable zone.
13. An optoelectronic document reader according to claim 12 wherein said illumination produced by said banks is of comparable intensity to avoid saturation of said image sensor.
14. An optoelectronic document reader according to claim 10 wherein said illumination of first light sources has a peak wavelength of 370nm.
15. An optoelectronic document reader according to claim 14 wherein said illumination of said second light sources has a peak wavelength of 650nm.
16. An optoelectronic document reader according to claim 15 wherein said illumination of said third light sources has a peak wavelength of 850nm.
17. An optoelectronic document reader according to claim 1 wherein said first indicia comprises encoded information.
18. A method for automated reading of first indicia in a machine readable zone of a document, said first indicia being invisible when illuminated with visible light and visible when illuminated with invisible light, said method comprising:
(a) providing a reading surface for placement of a document comprising said machine readable zone;
(b) providing a plurality of UV LED first light sources spaced apart from said reading surface and configured for illuminating said machine readable zone of a document on said reading surface with invisible light of a predetermined ultraviolet frequency range when said first light sources are activated so as to cause said first indicia to become visible, said first indicia comprising UV
fluorescent matter configured for emitting visible light when illuminated by said invisible light of said predetermined ultraviolet frequency range;
(c) providing an image sensor configured for capturing an image defined by light focussed thereon and producing electronic data representative of said captured image;
(d) providing an optical path extending between said reading surface and said image sensor and comprising a lens configured for focussing light defining an image onto said sensor;
(e) providing an optical filter within said optical path, said optical filter configured for removing reflected light of said first light sources; and, (f) providing a document controller configured for identifying said indicia from said captured image and outputting said identified indicia for display and/or processing;
whereby a document image comprising said first indicia defined by light emitted and/or reflected by said machine readable zone of said document on said reading surface when said first light sources are activated, is transported to said sensor via said optical path and captured by said sensor.
19. A method according to claim 18 whereby said optical filter is positioned between said lens and said image sensor.
20. A method for automatically reading first indicia in a machine readable zone of a document, said first indicia being invisible when illuminated with visible light and visible when illuminated with invisible light, said method comprising:
(a) illuminating, with invisible light of a predetermined ultraviolet frequency range, said machine readable zone of a document placed on a reading surface, whereby said illuminating comprises activating a plurality of UV LED first light sources spaced apart from said reading surface so as to cause said first indicia to become visible, said first indicia comprising UV fluorescent matter configured for emitting visible light when illuminated by said invisible light of said predetermined ultraviolet frequency range;
(b) optically filtering light within an optical path extending between said reading surface and an image sensor, for removing reflected light of said first light sources;
(c) focussing light defining a document image, within said optical path, onto said image sensor; and, (d) identifying said indicia from said document image focussed onto said image sensor, for display or processing;
whereby said document image comprising said first indicia is transported to said sensor via said optical path when said first light sources are activated.
CA 2375577 2002-03-07 2002-03-07 Optoelectronic document reader for reading uv / ir visible indicia Active CA2375577C (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CA 2375577 CA2375577C (en) 2002-03-07 2002-03-07 Optoelectronic document reader for reading uv / ir visible indicia

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
CA 2375577 CA2375577C (en) 2002-03-07 2002-03-07 Optoelectronic document reader for reading uv / ir visible indicia
DE2003109659 DE10309659A1 (en) 2002-03-07 2003-03-06 Optoelectronic document reader has light sources to illuminate machine readable zone with fixed frequency causing indicia to become visible, and sensor to produce electronic data of captured image
JP2003061594A JP2004127235A (en) 2002-03-07 2003-03-07 Optoelectronic document reading apparatus and method for reading indicia
AU2003200909A AU2003200909B2 (en) 2002-03-07 2003-03-07 Optoelectronic Document Reader for Reading UV / IR Visible Indicia
CN 03106900 CN1288892C (en) 2002-03-07 2003-03-07 Photoelectric file reader for reading UV/IR visual mark
HK03109275A HK1056941A1 (en) 2002-03-07 2003-12-20 Optoelectronic document reader and reading method for reading uv/ir visible indicia

Publications (2)

Publication Number Publication Date
CA2375577A1 CA2375577A1 (en) 2003-09-07
CA2375577C true CA2375577C (en) 2006-05-02

Family

ID=27810537

Family Applications (1)

Application Number Title Priority Date Filing Date
CA 2375577 Active CA2375577C (en) 2002-03-07 2002-03-07 Optoelectronic document reader for reading uv / ir visible indicia

Country Status (6)

Country Link
JP (1) JP2004127235A (en)
CN (1) CN1288892C (en)
AU (1) AU2003200909B2 (en)
CA (1) CA2375577C (en)
DE (1) DE10309659A1 (en)
HK (1) HK1056941A1 (en)

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20070138295A1 (en) * 2005-12-21 2007-06-21 White Daniel F Method for authenticating an item
CN101443692B (en) 2006-05-12 2012-11-21 克瑞尼股份有限公司 Micro-optic film structure that alone or together with a security document or label projects images spatially coordinated with static images and/or other projected images
US8780206B2 (en) * 2008-11-25 2014-07-15 De La Rue North America Inc. Sequenced illumination
US8265346B2 (en) 2008-11-25 2012-09-11 De La Rue North America Inc. Determining document fitness using sequenced illumination
US8749767B2 (en) 2009-09-02 2014-06-10 De La Rue North America Inc. Systems and methods for detecting tape on a document
DE102009044124A1 (en) 2009-09-29 2011-03-31 Pharmacontrol Electronic Gmbh Method and device for detecting information applied to packaging
WO2011088590A1 (en) 2010-01-21 2011-07-28 Metrologic Instruments, Inc. Indicia reading terminal including optical filter
US8408468B2 (en) 2010-12-13 2013-04-02 Metrologic Instruments, Inc. Method of and system for reading visible and/or invisible code symbols in a user-transparent manner using visible/invisible illumination source switching during data capture and processing operations
RU2444064C1 (en) * 2011-02-04 2012-02-27 Общество С Ограниченной Ответственностью "Конструкторское Бюро "Дорс" (Ооо "Кб "Дорс") Device for viewing security marks on document
KR101109610B1 (en) * 2011-04-25 2012-01-31 주식회사 네오랩컨버전스 A film recorded with code, reader used therefor, electronic device equipped with display covered with the film
DE102011082174A1 (en) 2011-09-06 2013-03-07 Bundesdruckerei Gmbh Device for mobile recognition of a document
US9053596B2 (en) 2012-07-31 2015-06-09 De La Rue North America Inc. Systems and methods for spectral authentication of a feature of a document
AT514659A1 (en) * 2013-07-16 2015-02-15 Ait Austrian Inst Technology Method for testing an article for authenticity

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6269169B1 (en) * 1998-07-17 2001-07-31 Imaging Automation, Inc. Secure document reader and method therefor

Also Published As

Publication number Publication date
JP2004127235A (en) 2004-04-22
CA2375577A1 (en) 2003-09-07
CN1288892C (en) 2006-12-06
AU2003200909A1 (en) 2003-10-02
AU2003200909B2 (en) 2007-11-01
DE10309659A1 (en) 2004-01-15
HK1056941A1 (en) 2007-03-16
CN1458618A (en) 2003-11-26

Similar Documents

Publication Publication Date Title
US7427030B2 (en) Security features for objects and method regarding same
US6470093B2 (en) First-order authentication system
EP2110776B1 (en) Optical authentication
JP5398889B2 (en) Authenticity verification
US6347163B2 (en) System for reading two-dimensional images using ambient and/or projected light
KR101168001B1 (en) Authenticity verification methods, products and apparatuses
US6385352B1 (en) System and method for reading and comparing two-dimensional images
JP5654541B2 (en) Method and apparatus for creating and subsequently verifying authentic printed articles
US5739518A (en) Autodiscrimination for dataform decoding and standardized recording
US6985607B2 (en) System and method for authenticating objects
US20040081332A1 (en) Apparatus and method for document reading and authentication
CN1295642C (en) Validation and verification method
US9224258B2 (en) Image reading device
DE60112890T2 (en) Method of monitoring documents
US5574790A (en) Fluorescence authentication reader with coaxial optics
US20120075442A1 (en) Handheld portable device for verification of travel and personal documents, reading of biometric data and identification of persons holding these documents
US7687271B2 (en) Covert authentication method and apparatus
US20150312440A1 (en) Apparatus and methods for computerized authentication of electronic documents
US7092583B2 (en) Apparatus and method for detecting the authenticity of secured documents
US7885428B2 (en) Automatic microparticle mark reader
US20130306728A1 (en) Systems and methods to read machine-readable symbols
US9378404B2 (en) Machine-readable symbols
US6269169B1 (en) Secure document reader and method therefor
EP1295263A1 (en) Use of communication equipment and method for authenticating an item, unit and system for authenticating items, and authenticating device
EP0721717B1 (en) Authentication system and method

Legal Events

Date Code Title Description
EEER Examination request