Abstract: A nonvolatile electro-optical read-only memory includes a substrate on which is printed (or otherwise inscribed) a complex symbol or "label" with a high density two-dimensional symbology, a variable number of component symbols or "codewords" per row, and a variable number of rows. Codewords in alternating rows are selected from mutually exclusive subsets of a mark pattern such as a (17,4) mark pattern. The subsets are defined in terms of particular values or a discriminator function, which is illustrated as being a function of the widths of bars and spaces in a given codeword. In the illustrated embodiment, each subset includes 929 available codewords; that, plus a two-step method of decoding scanned data, permitting significant flexibility in defining mappings of human-readable symbol sets into codewords. The memory may be used in conjunction with a scanner and a suitable control system in a number of applications, e.g., robotic operations or automated microfilm searching.

Abstract: A scanning system for orienting bar codes use a first stage made up of a low-resolution scanner and a digital signal processor (DSP), and a second stage made up of a high-resolution scanner and a decoder. The first stage scans the surface of an object to obtain an image, which the DSP analyzes to determine the location and orientation of any bar codes. The DSP does this by dividing the image into windows and finding the windows which contain part of a bar code. The second stage receives the results from the DSP and scans the bar code on the object.

Abstract: A method for decoding an analog waveform corresponding to a symbol comprises detecting the extrema locations of the waveform, and creating a feature vector from these extrema locations. The feature vector is compared to stored reference arrays corresponding to each symbol from an alphabet of possible symbols using statistical pattern recognition techniques to decode the waveform. The invention also features an analog waveform decoder that has reference storage for holding reference arrays, and a processor that creates and decodes a feature vector for the analog waveform.

Abstract: A holographic grating element is provided which enables tracing different scan lines. The element is divided into a plurality of sectors. A first grating pattern is provided which diffracts a beam in one direction, and a second grating pattern is next to the first and diffracts the scan beam in the reverse direction. Sectors can be produced with different sector sizes to enable scanning at different rates in the reverse direction, or in successive scans in the same direction. Angle relationships are described to produce diffraction patterns for a desired relationship between disc rotation and the angle of the scan line.

Abstract: A portable, conveniently usable, and inexpensive non-contact bar code verifier permits testing of bar code labels at some arbitrary but constant distance from the verifier. Means are provided for analog analysis of bar code label contrast levels, and for derivation of new, instructive indices characterizing the readability and print quality. Additionally, a new method for determination of absolute bar code label dimensions is disclosed. The method of calibration for arbitrary scanning distance and angle standardizes not only the verifier's ability to measure absolute dimensions at unknown distances, but also its ability to discern contrast under arbitrary lighting conditions and scanning equipment. This is accomplished by employing calibration standards of known characteristics. Bar code verification information may be stored and/or employed for a variety of control and analytical functions as recognized in the art.

Abstract: Optical scanning of one- and two-dimensional barcode symbols is carried out first in an aim mode wherein the symbol is scanned using a first scan pattern that is relatively small and dense so as to be visible to the user and thereafter using a second, larger and more robust scan pattern for decoding. During aiming, the symbol is partially decoded to determine type and orientation, and this information is applied to control the angle of the scan pattern produced, the rate at which the scan pattern is increased for optimum decoding, and the ultimate pattern size. Preferred scan patterns, as well as unique scan mechanisms, are described.

Abstract: A scanning system has a plurality of optical scan units. Each optical scan unit includes means for emitting light toward an item bearing an indicia. Each optical scan unit also includes means for receiving light reflected from the indicia and generating signals corresponding to the intensity of the reflected light. Also provided is a central control unit which includes means for combining together signals corresponding to the signals generated by at least two of the scan units to fully decode information contained on the indicia.

Abstract: A numbering and reading system with record having two-dimensional erasable bar code or a removable label with a two-dimensional bar code is disclosed. The bar code can be PDF417.

Abstract: An optical scanner module for directing a light beam to scan an optically encoded symbol includes an optical element mounted for oscillatory motion to scan the light beam in one direction by a flex element capable of torsional flexure. This oscillatory motion is induced by the interacting magnetic fields established by a permanent magnet mounted to the flex element and an electromagnetic coil driven by an AC current. Bidirectional light beam scanning is achieved by mounting an assembly of the flex element, optical element and permanent magnet to one or more additional flex elements for oscillatory motion to scan the light beam in a second direction. This oscillatory motion is induced by the inclusion of an additional permanent magnet and/or electromagnetic coil.

Abstract: A scanner for reading indicia having portions of differing light reflectivity has means for directing a light beam from the scanner towards the indicia and collecting reflected light returning from the indicia. The scanner includes a scanning arrangement with a scanner component, such as a mirror. First and second vibratory means support the scanner component for angular oscillatory movement to scan the light beam in first and second orthogonal scan directions. The scanning arrangement includes read-start means for moving the scanner component to simultaneously scan the light beam in the first and second scan directions.

Abstract: A scan head is adjustably mounted in a ball-and, socket joint on a scan module or housing of an electro-optical system for reading coded indicia. The scan head is movable about three mutually orthogonal axes intersecting within the scan head, thereby steering a light beam emitted from the head and/or steering a field of view of a sensor.

Abstract: A packet data transmission system is used to link a number of remote hand-held data-gathering units such as bar code readers to a central computer which maintains a database management system. Data packets are sent from the remote units by an RF link to intermediate base stations, then sent by the base stations to the central computer by a serial link. Direct sequence spread spectrum modulation is used for the RF link. The remote hand-held units initiate an exchange using RF transmission to and from the base stations, receiving only during a rigid time window following a transmission from the remote unit. The base stations cannot initiate communication to the remote units, but instead send data to the remote units only as part of the exchange.

Abstract: A symbol scanning system which adaptively changes scanning system parameters including light beam pattern and focus to improve barcode readability. The scanning system including; a scanner, responsive to coordinate control signals, for directing a light beam in a pattern at a symbol at a predetermined location, detecting a reflected portion of the light beam, and generating a feedback signal corresponding to the detected portion of the reflected light beam, a microprocessor, responsive to the feedback signal, for generating pattern control signals, and a pattern generator for generating the coordinate control signals in responsive to the pattern control signals and for determining the light beam pattern.

Abstract: A wall-mounted, hands-free scanner capable of having its field of view adjusted using a pivot structure with a position-holding mechanism. The spacing of the field of view from the wall can be quickly adjusted to accommodate different size objects and different placement of indicia on objects. The scanner includes a base member configured to be installed on a vertical surface, a scanning unit including a light scanning source directing a light beam across a field of view toward an indicia located within the field of view, a pivot structure connecting the scanning unit to the base member (the pivot structure having a generally horizontal axis of rotation about which the scanning unit rotates relative to the base member), and a position-holding mechanism within the pivot structure.

Abstract: In an optical scanning module, for reading indicia with portions of differing light reflectivity, having a light emitter assembly for emitting a light beam towards the indicia, and a detector for receiving light reflected back from the indicia and producing an electrical signal corresponding to the differing light reflectivity of the indicia, an optical scan module component is provided which includes two circuits on respective circuit boards which are angularly mounted, and preferably orthogonally mounted, to each other. An electrical cable connects the circuits to each other so as to operate together to produce signals to drive the emitter assembly and to process the electrical signal produced by the detector.

Abstract: A scanning arrangement in a scanner incorporating a scan element which is capable of the repetitive high-speed scanning of indicia having parts of different light reflectivity; for example, such as barcode symbols, and more particularly, pertains to the operation of a scanning arrangement of the type which, at high scanning speeds, will enable the scanning of indicia in variable and specified omni-directional scanning patterns. The variable omni-directional scanning pattern is attained through control over the electrical energy input to a read-start device for activating the scan element of the scanner for vibratory motion between first and second pairs of scan end position, in which the energy input is controlled and varied, and the scan element is rotated, in a manner so as to enable the scan element to implement the aforementioned omni-directional scanning patterns over the indicia.

Abstract: An optical system for use in a scanning system for reading symbols. The scanning system includes a head for containing the optical system. The optical system comprises a light source for generating a beam of light. A scanner is provided for directing the beam of light towards the symbol and scanning the beam of light across the symbol. Further, in accordance with the present invention, a dead zone-reducing optical system is provided in the head for lengthening the optical path length between the light source and the scanner to reduce the length of the dead zone exterior of the head. A collector collects light reflected from the symbol and directs it to a detector. The collector includes at least two sectors each having different focal lengths. The detector detects the variable intensity of the returning portion of the reflected laser light over a field of view, and generates an electrical signal indicative of the detected variable light intensity.

Abstract: A handheld data entry terminal includes a housing and a scanning head mounted to the housing for pivotal movement between at least first and second reading positions. The scanning head, when actuated, optically scans an encoded symbol and detects light reflected from the encoded symbol while in either of the first and second reading positions. As desired, a terminal user can establish either one of first and second trigger switches mounted to the housing as a scanning head actuating switch, leaving the other of the trigger switches to be established as a shift key for determining the type of characters entered by alphanumeric data entry keys of a keypad also mounted to the housing in conjunction with an LCD display.

Abstract: A record contains a graphic image and an information area which are interrelated to discourage misuse of the record. The information area can overlay the graphic image and include information encoded in a error-correctable, machine-readable format which allows recovery of the information despite distortion due to the underlying graphic image. The record may also represent the image by words similar in form to words in the information area. Both the information and graphic words can then be altered when an action regarding the record takes place.

Abstract: A miniature high speed bar code scanning element is housed within an industry standard PCMCIA card for implementation in personal computing devices. In one embodiment, the scan element is mounted on the exterior of the card for pivotal movement about vertical and horizontal axes.