Abstract: Methods, systems, and programming for identifying a person are presented. In one example, a first set of candidates is determined based on a fingerprint image acquired from a finger of the person. A second set of candidates is determined based on a finger vein image acquired from the finger. The person is recognized based on the first and/or second set of candidates.

Abstract: A counterfeit paper currency detector includes a casing receiving a delivering device, a driving device, and a paper currency detection device. The casing includes a paper currency inlet at an end thereof and a paper currency outlet at another end thereof and aligned with the paper currency inlet. The delivering device includes a delivering body having two ends intercommunicating with the paper currency inlet and the paper currency outlet, respectively. The driving device is mounted at upper and lower sides of the delivering body and is configured to drive a bill inputted via the paper currency inlet to move through the delivering body and then exit the paper currency outlet. The paper currency detection device is mounted to a rear end of the delivering device and is configured to examine whether the bill passing through the delivering body is a counterfeit bill.

Abstract: An electronic device includes a housing main body having an opening, a transparent plate attached to an outer face of the housing main body so as to cover the opening, a light-emitting diode (LED) that is disposed in the housing main body to face outside via the opening and that illuminates a bar-code with illumination light, and an imaging unit that is disposed in the housing main body to face outside via the opening and that detects reflected light reflected on the bar-code in the illumination light. The housing main body is integrally formed with a shade configured to shade reflected light reflected on the transparent plate in the illumination light illuminated from the LED such that the illumination light does not enter into the imaging unit.

Abstract: Systems and methods are provided, at an accessible electronic device having a visual display with a touch-sensitive surface, for displaying on the visual display a graphic visualization having a plurality of graphic elements, and in response to detecting a navigation gesture by a finger on the touch-sensitive surface, selecting one of the plurality of graphic elements and outputting accessibility information associated with the selected graphic element. Systems and methods are also provided for generating computer code for converting a data set into graphic visualization annotated with accessibility information.

Abstract: An apparatus includes a light emitting diode operative to emit mostly invisible light within an invisible bandwidth, and a scattering surface configured to scatter a first portion of the invisible light from the light emitting diode out of the window. The scattering surface is also partially transparent to allow a second portion of the invisible light from the light emitting diode to pass through the scattering surface and strike the reflector that is configured to reflect at least some of the second portion of the invisible light towards the window. The apparatus further includes a photodetector configured to detect returned invisible light from the target object.

Abstract: An optical recognition pattern for length measurement is mounted on an optical contact surface and includes a plurality of optical recognition units, each of which corresponds to a length value. The sequence of the optical recognition units on the optical contact surface is consistent with that of the corresponding length values in such a way that the optical recognition pattern imitating the conventional measuring ruler can be constituted. Besides, the optical recognition pattern can further work with an optical recognition device to constitute a length measurement system that the optical recognition is applied to.

Abstract: A method and apparatus comprising an imaging system (10) with safety control for imaging target objects having a scanning arrangement (14) including a sensor assembly (22) for capturing an image from a target object. The sensor assembly (22) has a field-of-view focused by an optical arrangement (24) onto a sensor array (28). The imaging system further comprises an illumination assembly (18) having a housing (30), illumination source (38), light pipe (42), and projection lens (36). The illumination assembly (18) provides light energy toward the sensor assembly field-of-view for illuminating the target object to be imaged on the sensor array (28). The light pipe (42) comprises a multi-walled tapered body (52) having an input face (40). The walls of the body (52) create mirrored images of the illumination source (38), together with the projection lens redistribute the amount of light energy directed at the eyes of a human.

Abstract: A beam direction sensor for determining the direction of each beam in an array of light beams. The invention basically consists of a screen positioned to intersect the array of beams and a video camera to record the position of the images of the intersections. The screen can be any of a wide variety of screens that produce an image of the beams when illuminated with the beam. These include frosted glass and various diffusers. A preferred screen is a holographic diffusers.

Abstract: Optical sensor for detecting a code on a substrate which, in use, moves with respect to the optical sensor. The sensor comprises an optical detector for determining a value of a reflective property of the substrate, wherein the optical detector views the substrate along an optical axis, a code analyser for determining the detected code on the basis of a variation of the value of the determined reflective property in time, a first illumination source for illuminating the substrate along the optical axis, a second illumination source for illuminating the substrate in a direction at a non-zero angle with respect to the optical axis, and a control unit having a first operational mode wherein the first illumination source switched on and the second illumination source is switched off, and having a second operational mode wherein the first illumination source is switched off and the second illumination source is switched on.

Abstract: The controller of the present invention includes an optical navigation system which is responsive to movement, velocity of position of a rotatable platter. The optical navigation system is responsive to rotation of the rotatable platter and is further responsive to at least one degree of freedom of tilting of the rotatable platter. The rotatable platter typically includes a textured pattern so that the optical navigation system can acquire sequential surface images of the textured pattern.

Abstract: A system for imaging an object comprising a surface for receiving the object to be imaged and an imaging device. The imaging device comprises a housing and a fixed focusing optical device mounted to the housing, whereby the fixed focusing optics comprises a lens for focusing light reflected from the object. A plurality of independent linear imaging sensors are positioned in the housing at different distances from the fixed focusing lens so that a face of each of the plurality of independent linear imaging sensors is aligned parallel to the surface. A processor is coupled to the plurality of independent linear imaging sensors for receiving an output signal from each of the plurality of independent linear imaging sensors representative of the reflected light. The lens defines a plane parallel to the surface, and the plurality of independent linear imaging sensors are adapted to receive reflected light from the object.

Abstract: The device for the acquisition and automatic processing of data obtained from optical codes comprises a CMOS optical sensor; an analog processing unit connected to the optical sensor; an analog/digital conversion unit connected to the analog processing unit; a logic control unit connected to the CMOS optical sensor, the analog processing unit and the analog/digital conversion unit; and a data-processing unit connected to the logic control unit and the analog/digital conversion unit. The CMOS optical sensor and at least one of the analog processing, analog/digital conversion, logic control and data processing units are integrated in a single chip. The data processing unit processes the digital signals corresponding to the image acquired by the CMOS sensor and extracts the optically coded data.

Abstract: The invention is directed to an arrangement and a method for checking optical diffraction structures (e.g., kinegrams) on documents. The object of the invention, to find a novel possibility for checking optical diffraction structures on documents which permits detection of the presence and authenticity of optical diffraction structures quickly and economically with respect to apparatus, is met according to the invention in that the sensor unit is arranged orthogonally above the support surface of the document, and in that the illumination unit contains at least two monochromatic light sources which are arranged so as to emit light bundles at defined incident angles with respect to a surface normal of the document directed to the diffraction structure and which can be switched on sequentially.

Abstract: In one embodiment, an optical reflective information reading sensor has a single casing that accommodates a light-emitting element portion for emitting light for reading information, an emission-side lens portion for irradiating a target information face of a target with irradiation light, which is the light emitted by the light-emitting element portion, the target being disposed outside the optical reflective information reading sensor, a reception-side lens portion for forming an image of diffusely reflected light, which is reflected light of the light irradiated on the target information face, and a light-receiving element portion for receiving the diffusely reflected light whose image has been formed. The optical reflective information reading sensor detects a target information pattern, which is target information such as a barcode on the target information face.

Abstract: An optical code reader for reading optical codes in any orientation with a preferred depth of field (DOF), the optical code reader including imaging sensor arrays arranged at angles to one another and tilted in accordance with the Scheimpflug principle to allow for omni-directional reading and a preferred DOF. In addition, an optical code reader may also include an optical device to rotate an image as it is projected upon a stationary tilted image sensor array. Still further, an optical code reader may include a rotating imaging sensor array tilted in accordance with the Scheimpflug principle to allow for omni-directional reading with a preferred DOF.

Abstract: The present invention provides a control method for moving and positioning multiple lens of a scanner to their accurate position. The method mainly uses a linear reference image, such as a calibration paper with some marks in the scanning range, taken by a specific lens to a CCD for verifying if the lens is well positioned according to a decision rule. The lens is controlled to move to its correct position by the continuous feedback signals from the CCD, so the accuracy and reliability of the positioning can be kept without being influenced from any worn-out of frequent movements of the mechanism.

Abstract: An optical barrier is provided by an optical barrier unit that is made up of one or more emitter element modules and one or more receiver element modules. The emitter modules present are controlled by a control circuit to emit modulated beams encoded in a particular manner. In this regard, a particular beam of each emitter module is encoded with one of a pair of unique words that both indicate the identity of the module emitting that beam and further indicate a different binary word value depending on which of the pair is used as part of a further code that will identify the barrier unit. If more than one emitter module is part of the optical barrier, a corresponding number of particular beams, one for each emitter module present, are modulated with appropriate ones of other pairs of unique words to both identify those modules and to provide the proper binary word value as a further part of the optical barrier unit's identification number.

Abstract: This optical scanner for testing the validity of a bill transported through a bill validator includes lower and upper members spaced to allow a bill to pass therebetween, at least one member including a light transmissive area. A light emitting element is arranged to direct light through the light transmissive area and a light receiving sensor is arranged to receive light from the light emitting element during passage of bill (B) therebetween. The light transmissive area includes a recessed portion to provide non-contact face portions of the light transmissive area spaced from the bill to preclude the transfer and build-up of dirt and abrasion of these areas.

Abstract: A self-monitored optical sensor having a code plate having a plurality of tracks disposed thereon. Each of the tracks comprises a pattern of reflective and absorptive segments that form a code that is indicative of a discrete position of the code plate. The code plate further includes a monitoring track that encodes a number of expected absorptive or reflective segments in the code plate at each discrete position. A detector circuit compares the number of absorptive or reflective segments detected and the number of expected absorptive or reflective segments in order to determine if there is a fault in the code plate.

Abstract: In an optical character reading apparatus for optically reading a character image to produce a character signal representative of the character image, a collation and judgement circuit (22) compares a modified image with each of predetermined reference images memorized in a dictionary (21). A character detecting arrangement (11, 12) detects the character image to produce a detected image. A deleting arrangement (15, 16) partially deletes the detected image to produce a partially deleted image. A modifying arrangement (17, 18) modifies the partially deleted image into the modified image by the use of a reference signal produced in a reference signal producing arrangement (13, 14). It is preferable that the reference signal producing arrangement produces the reference signal in accordance with the detected image.

Abstract: A robotic arm calibration system is described which comprises a video line scan camera vision system used in conjunction with a plurality of novel "N"-shaped targets in an automated tape storage library. The targeting system of the present invention provides, with a single horizontal video scan of the target, all of the data necessary to enable calculation of a reference point of the robotic arm with respect to each target to thereby obtain precise robotic arm calibration in relationship to the library system workspace. The position of the robotic arm is determined using the vision system in conjunction with calibration targets which are located within the tape cartridge library, in addition to a target located on the robotic arm. The present system functions independently of the spacing between the arm retrieval mechanism and the tape cartridge storage cells.

Abstract: A bar code scanning system having a focusing lens for focusing scanning light beams in a first focal plane includes a slide member supporting a transparent substrate which enables the focusing lens to focus the light beams in a first focal plane through which a coded indicia is moved. When a coded indicia is moved closer to the focusing lens, the intensity of the reflected light beams increases which is detected by a detector member whose output signals operate a drive member coupled to the slide member, moving the slide member to a position removing the substrate from the path of light beams enabling the focusing lens to focus the light beams in a second focal plane which is closer to the focusing lens than the first focal plane.

Abstract: Apparatus that enables an optical transceiver (14) to communicate data as a bar code reader or by way of modulated light. A lens assembly (22) adjusts the focal distance of the optical transceiver (14) to enable it to communicate in these multiple modes. A control circuit (16) and microprocessor (12) are coupled to the optical transceiver (14) and are responsive to the focal distance setting of the lens assembly (22) for selecting the appropriate communication mode. The apparatus is of particular value in low-power, portable environments, such as in calculators or other portable computing devices.

Abstract: Disclosed is a signal processing apparatus comprising a sensor whose impedance varies according to changes in quantity sensed thereby, a power source applying a voltage to the sensor, a current/voltage conversion circuit for converting an output of current flowing through the sensor to a voltage signal, and a feedback means for passing a current corresponding to the output voltage of the current/voltage conversion circuit through the sensor.

Abstract: A method and apparatus for processing an embossed card on which embossed characters are formed. The apparatus performing the method by optically reading embossed characters and producing corresponding electrical signals. The produced corresponding electrical signals are then compared with characteristic data of a predetermined set of characters. From this comparison, identification of the embossed characters is determined.

Abstract: A relative positional relation detecting system has a detector for the recognition of and inspection by use of a predetermined identification mark provided on each of at least two members to be put in a predetermined relative position to each other. The detector comprises an irradiation device for irradiating the identification mark with rays of light, a light detection device for detecting reflected rays of light from the identification mark, and a judging device for judging whether or not the members are put in the predetermined relative position, depending on a detection signal from the light detection device.

Abstract: A pen-type bar code reader uses a reflector formed on a concave lens surface of a convex lens system with respect to a bar code detector, except a region for transmitting a light flux. The convex lens system is mounted so that its optical axis is angled with respect to the light flux from the detector, and a bar code illuminating light source is provided in a position between the detector and the convex lens system and opposite to the light flux from the detector with respect to the optical axis of the convex lens system.

Abstract: In order to meet the requirements for laser radiation safety, namely laser output which can enter the naked human eye indefinitely and cause no discernible damage (Class I emission limit) in a code symbol (bar code) scanner, a mode controller is used for generating a laser enabling the signal so as to turn the laser on in a search mode until the symbols are acquired and in an in-code mode while the symbols are being scanned. When the laser is turned on it operates at a power output which would exceed the Class I emission limits if operated continuously. Circuitry is provided for operating the mode controller so that the laser is not enabled to turn on for a period long enough to exceed Class I limits. Such circuitry may be an integrator or accumulator which responds to the time that the mode controller turns the laser on and which provides an output for inhibiting the mode controller from turning the laser on for a period of time sufficient to prevent the Class I emission limit from being exceeded.

Abstract: In optical mark recognition apparatus the light transmitter has two light sources 11, 12 which can be selectively switched on and which transmit light beams of different spectral compositions. A semi-permeable mirror 15 directs the light beams 13, 14 of both light sources 11, 12 along a common optical path 16 (FIG. 1).

Abstract: A hand-held bar-code reader (bar-code wand) which forms part of an optical reading device and is capable of being led by hand over the bar code, comprises a storage circuit for storing the data pulse train corresponding to the scanning signals, and a photo- or sound-transmitter by which the stored data pulse train is transmitted to a separate equipment, such as a video tape recorder or radio receiver provided with a photo- or sound-receiver and an evaluating circuit. In another example of embodiment, the equipment comprising the evaluating circuit, contains a reader compartment provided with a connector member for connection to the reader which, following the scanning and storing of one or more words of the character code, is returned to its compartment and is automatically read out via the connector contacts.

Abstract: An electrical output signal from an electro-optical code reader is amplified (U1) to develop a first signal which is applied to a positive peak detector (U2D1, C2) and a negative peak detector (U3, D2, C3). The positive peak detector provides a second signal whose voltage level follows that of the first signal as the first signal increases, from the time that the voltage level of the second signal is brought substantially equal to that of the first signal to the time that the first signal begins to decrease, with the voltage level of the second signal thereafter being maintained substantially constant. The negative peak detector provides a third signal whose voltage level follows that of the first signal as the first signal decreases from the time that the voltage level of the third signal is brought substantially equal to that of the first signal to the time that the first signal begins to increase, with the third signal thereafter being maintained substantially constant.

Abstract: A portable instant bar code reader including a hand-held reader unit having a flash type illuminator. The flash type illuminator is triggered to illuminate a bar code label positioned adjacent to a light receiving window of the reader. Reflections from the bar code label are transmitted through the light receiving window and are focused onto a photodiode array by means of a lens. The photodiode array is scanned automatically, and read-out pulses are developed into logic which represents the information contained in the bar code.

Abstract: An adaptive threshold optical reader for detecting optically encoded information when positioned within an optical path, including a light source for producing light energy along the optical path, a light detector responsive to the light energy along the optical path and for producing an ouput signal in accordance with the light energy detected by the light detector, means responsive to the output signal from the light detector and with the means having at least two states and with the means in a first state producing an adaptive threshold signal when there is no optically encoded information positioned within the optical path and with the adaptive threshold signal representative of the output signal from the light detector with a threshold level of optically encoded information and adaptive to optical changes and with the means in a second state for producing an information signal representative of the output signal from the light detector when there is optically encoded information positioned within the opt

Abstract: A bar code reader employs a microprocessor for decoding data contained in a bar code record and a logarithmic converter ahead of the microprocessor for providing to the microprocessor signals indicative of the logarithms of the widths of the scanned bars and spaces. The base of the logarithms used by the logarithmic converter is selected in a predetermined manner to maximize the resolution of the system for the particular microprocessor used, and to reduce the complexity of the system.

Abstract: Signal processing circuitry for a bar-coded data input terminal having a bar-code reading device, such as light pen, for reading bar-coded identity data, from bar-coded identity labels, attached to items to be identified for instance takes an output signal from the reading device and derives a processed signal in which changes of signal level are cleaner than corresponding level changes in the output signal. The signal processing circuitry employs a high gain operational amplifier to an input of which the output signal is passed through a capacitor. The amplifier has a capacitor and two diodes, with their conduction directions opposite, connected in parallel between the input and the output of the amplifier, from which an amplified signal opposite to the reading device output signal is delivered. A threshold detector receives the amplified signal and provides a processed signal in which signal level changes in dependence upon the amplified signal passing through threshold levels.

Abstract: A data card and data card reader combination including a data card incorporating two data tracks consisting of a plurality of perforations spatially arranged to represent encoded data. A card reader incorporates at least one radiant energy source, two radiant energy detectors, and guide means for guiding the movement of the data tracks between the radiant energy source and the radiant energy detectors whereby a first data pulse train and a second data pulse train corresponding to the perforations of said data tracks may be produced. An "OR" circuit receives the first data pulse train producing a clock pulse train, which in turn is fed to a holding shift register. A selector circuit selects the data pulse train exhibiting the first appearing pulse and in turn feeds the selected data pulse train to the holding shift register.

Abstract: Apparatus for storing and reading data in association with a card which has a timing track comprising at least three different kinds of optically-readable timing markings arranged in the timing track in a cyclic sequence, and a data track, the apparatus including three optical timing sensors respectively responsive to the three different kinds of timing markings, and a reading direction detector controlled by the timing sensors.

Abstract: Apparatus for detecting marks or other objects by comparing a decrease in reflected light while the mark or object is moving across optics, to the light reflected before the mark or object was encountered by the optics. A threshold reference voltage level is derived directly from the conductance level of a phototransistor prior to the introduction of the mark or object to be detected. This reference level is developed in such a manner as to cause it to be a dynamic voltage, varying percentage-wise as the conductance of the photo-transistor. The dynamic reference level so determined is thus always directly a portion of the level present before the mark or object to be sensed was introduced.

Abstract: An optical position code detector which senses information that is recorded on a record carrier. The record carrier preferably has scan marks for synchronizing operation of the detector and at least one track with positionally encoded data marks which include one or more imprinted alphanumeric characters. The detector includes photodetectors which sense light that is reflected from the record carrier. The intensity of the reflected light varies in dependence on whether or not data marks are present and also varies due to the presence of spurious marks on the record carrier. When a scan mark appears, a comparison circuit is activated which compares the voltage from each photodetector with a reference voltage which is cycled from a low magnitude to a relatively high magnitude. The comparison circuit distinguishes data marks from spurious marks with a high resolution. A logic circuit is connected to the comparison circuit to indicate whether or not a position code is present on the record carrier.

Abstract: A coincidence testing method for enhancing the reliability of output data from a label reader adapted to read a bar code consisting of a plurality of bars. Each bar in the bar code is scanned at a plurality of points and sets of binary symbols representative of the scanned points along each bar are obtained. Then the binary symbols in each set are ordered to correspond to the order of the scanned points or segments along each bar. Then coincidence tests are performed on successive pairs of binary symbols in each set to determine whether a reliable decision can be made for each bar.

Abstract: A method and apparatus for reading label bar codes in which a photoelectric signal representative of an optically scanned bar code label is differentiated. The positive and negative peaks of the differentiated signal are detected, and the time intervals between the peaks are measured by counter means to produce output signals representative of the bar code label. A multi-level threshold comparison technique is used to detect and predict the occurrence of positive and negative peaks.

Abstract: The method for reading information from a punched carrier, consists of modulating a radiation flux emitted by a radiation source by information holes of the punched carrier and then additionally modulating by an additional modulation means. The double-modulated radiation flux is then reflected by a reflector to a photosensitive input of a main converter which converts the radiation flux into a primary information signal. The primary information signal is then compared to a reference signal which changes according to the law of additional modulation, whereupon the preset signal is discriminated. The proposed device for effecting the method comprises a radiation source optically connected to a reflector through the information holes of the punched carrier, as well as through an additional modulation means. The additional modulation means can performthe functions of the reflector.

Abstract: An apparatus for making distance measurements with a high degree of accuracy and a means for interpreting and displaying the results on a digital readout. A binary encoded scale which exhibits a one to one correspondence with discrete locations on said scale and the coded information at those locations is used in making the measurements. The scale is made using photographic reducing techniques. An optical detection system, comprising a magnifying lens, a plurality of light conducting fibers and phototransistors is used to read digital information from the binary encoded scale. An electronic circuit accepts digital code from the optical detection system, decodes it and displays the resulting information on a digital readout.

Abstract: A novel optically readable message card having columns of marking areas thereon where the vertically adjacent marking areas in a column are horizontally staggered. Also, a template for the message card and having columns of horizontally staggered marking openings therein corresponding to the marking areas on the message card. The horizontal staggering arrangement assures that an unskilled user will make a sufficiently long mark in the marking area on the message card so that the mark can be read by commercially available optical mark reading equipment. Furthermore, the staggered openings in the template assure the structural strength of the template. Also, a structurally strong, easy-to-use template assembly including the template and a base plate designed to hold the message card and accurately align it with the template. Also, a method of economically mass-producing the template assemblies.

Abstract: A stack of documents are transported one-at-a-time, under control of an automatic machine. A machine readable card is inserted between preselected documents in the stack. When the transport detects a passage of the card through the transport system, the machine is commanded to perform a specific function. The exemplary machine described herein is a microfilm camera, and the illustrative functions are two side copying and batch or file marking.

Abstract: A detector for marks having a color which contrasts with the mark background employs a solid state light source projecting a light beam having a plurality of wave length components corresponding to a plurality of colored light wave lengths. The light beam may approach the appearance of white light. A pulse modulated detector or sensor is used for receiving light reflected from colored surfaces having contrasting colored marks thereon, wherein high ambient light level rejection is obtained and high signal to noise ratio is provided in a sensor output. The sensor output is gated to eliminate between pulse noise, and the gated output is integrated to obtain a reference signal to which the gated pulse is continuously compared. An increase or decrease in signal is used to provide a light or dark mark indication respectively as a result of the comparison. Feedback from the output suppresses signal instability which may exist at the edges of the detection threshold.

Abstract: A card on which at least a group of bar-coded information are printed is carried by a motor-driven carrier. The bar-coded information is sensed and converted into a group of parallel digital signals, which is compared with a previously stored data to check coincidence. The same bar-coded information is repeatedly sensed, converted, and compared as above and number of the coincidence times is counted until it has passed a read-in position driven by the card carrier. The card is accepted as readable when the number of coincidence times reaches a preset number. Otherwise, it is rejected by reversing the motor.

Abstract: A bar code is constructed from individual characters that are laid out along a first straight line. Each character is formed by a series of bars and spaces that are parallel to the first straight line and that are laid out along a second straight line which is perpendicular to the first straight line and which passes through the center of the character. The resulting bar code is scanned manually by an operator who propels a hand-held scanner across the bar code in a direction parallel to the first straight line. The hand-held scanner contains a linear photodetector array mounted opposite optical elements in such a manner that a line image of a bar code character roughly perpendicular to the first straight line is projected upon the linear array as the stylus passes over a character.

Abstract: An object-identifying system is described comprising at least one device for remotely identifying a plurality of objects bearing each a characteristic code in the form of a badge which has alternating reflective and non-reflective strip zones. The objects may be moving past the device but could also be motionless. When illuminated by a light source, the badge reflects a part of the incident light beam to an opto-electrical transducer which is formed by a number of diodes in a row. Control means allow the photodiodes to be switched on and off in succession to scan the badge. The length of the row of diodes is generally greater than the length of the code support in the scanning direction to allow for any possible disalignment between the support and the identification device.

Abstract: A photoelectric data card system is disclosed in which the cards are transmissivity-coded, so that light of a particular wave length and intensity is transmitted in varying degrees of different code digit representing areas of the cards, and thus the intensity of the light emerging from each of these code digit representing areas can be photoelectrically interpreted as the value of the digit represented by that area. A laminated card for use in this system is disclosed in which the transmissivity levels of the digit representing areas are provided by halftone printing on an inner lamination of dark-pigmented plastic card stock, and the inner lamination is sealed between two white-pigmented laminations of plastic card stock, the white-pigmented laminations being pigmented to such an extent that neither the location of the digit representing areas nor the values of the digits represented can be determined by casual inspection of the card.