Abstract: A method and apparatus for reading encoded symbols such as bar code labels at any orientation to a raster scanning device. Objects bearing encoded symbols are transported from one conveyor across a relatively narrow gap to a second conveyor, with a linear scanner positioned beneath the conveyors so as to read the encoded symbols through the narrow gap as the objects pass over. A pattern of virtual scan lines is selected over the two-dimensional imaging region according to the specifications of the images to be read. The pattern is generated by defining a family of parallel lines of a certain spacing and rotating the family by a specified angle until the two-dimensional imaging region is covered. In a preferred embodiment, only the data at selected raster locations on the virtual scan lines is stored and processed. One-dimensional signal processing methods are used to detect edges and decode the encoded symbols.

Abstract: A method and apparatus for reading bar codes or other images while reducing or eliminating the need for self-generated illumination. An image reader is preferably embodied as a handheld unit and comprises an efficient optical collection system including an aperture with a high aspect ratio and/or a multi-focal lens or lenses. An optically transmissive spacer affixed to the front of the handheld unit allows ambient light to be collected at close range, and a diffuser may be used to reflect ambient light from the handheld unit to provide additional illumination at close range. A masked CCD detector with rectangular pixels receives collected light and is coupled to an adaptive exposure circuit for preventing saturation of the CCD detector at high illumination levels. A correlated double sampling circuit coupled to the adaptive exposure circuit rejects common mode noise and allows operation in lower light levels.

Abstract: A method and apparatus for conditioning an input signal from an optical detector includes a controller for dynamically modifying adjustable delay elements connected to the input signal, thereby modifying characteristics of the signal conditioning circuitry. The method and apparatus determines the transitions between binary levels of an input signal such as a scanned bar code label by detecting zero crossings of an approximated second derivative of the input signal. Samples of the input signal are obtained by using delay lines, sample-and-hold circuits, an analog shift register or similar device. The first derivative of the signal is approximated by the slope of a straight line between two sampled points on the waveform. The second derivative is approximated by the difference between two first derivatives.

Abstract: A method and apparatus for reading bar codes or other images while reducing or eliminating the need for self-generated illumination. An image reader is preferably embodied as a handheld unit and comprises an efficient optical collection system including an aperture with a high aspect ratio and/or a multi-focal lens or lenses. An optically transmissive spacer affixed to the front of the handheld unit allows ambient light to be collected at close range, and a diffuser may be used to reflect ambient light from the handheld unit to provide additional illumination at close range. A masked CCD detector with rectangular pixels receives collected light and is coupled to an adaptive exposure circuit for preventing saturation of the CCD detector at high illumination levels. A correlated double sampling circuit coupled to the adaptive exposure circuit rejects common mode noise and allows operation in lower light levels.

Abstract: A laser bar code system is described which includes a first scan module releasably affixed to a housing, which scan module is readily interchangeable with and plug compatible with a second scan module which is configured at least partly differently from the first scan module. In addition, a partitioned scan module is described which comprises a first laser diode subsystem, a first scanning subsystem, a first collection subsystem, and a first signal processing subsystem, a selected one of which is releasably affixed to a chassis, and readily interchangeable and plug compatible with a second laser diode subsystem, a second scanning subsystem, a first collection subsystem, and a second signal processing subsystem, respectively, which is configured at least partly differently from the first.

Abstract: An optical system and method for data reading in which a light source generates an optical beam directed toward an object to be read and a variable aperture mechanism positioned in the outgoing light path establishes at least two separate focal planes. The variable aperture device may comprise a variable aperture system in which the size of the aperture is selectively varied about a range within the diffractive limit of the light beam. A preferred aperture mechanism is an electronically actuable mechanism with no moving parts which may include a liquid crystal aperture with one or more aperture regions which are selectively or consecutively activated. The optical system therefore establishes two or more separate waist locations from a single light source resulting in greater depth of field or multiple depths of field.

Abstract: In an optical scanning system, a method and apparatus for decoding labels of single or multiple block formats by stitching together partial label segments obtained from multiple optical scans across the label is provided. Partial scans are decoded into strings of character information which are assembled by locating sub-strings of common elements between two strings. Strings in which the common elements occur at the ends are merged by deleting one set of redundant common characters and joining the remaining characters in proper sequence. The method assembles strings in which the common elements occur in the middle of one or both strings by testing for valid string combinations made by deleting characters adjacent to the common sub-string, on opposing ends of each string, and merging the resulting strings. Feature characters, parity information, checksum digits, and other label structural characteristics are used to verify resulting strings and completed blocks and labels.

Abstract: A method and apparatus for determining the transitions between binary levels of an input signal such as a scanned bar code label by detecting zero crossings of an approximated second derivative of the input signal. Samples of the input signal are obtained by using delay lines, sample-and-hold circuits, an analog shift register or similar device. The first derivative of the signal is approximated by the slope of a straight line between two sampled points on the waveform. The second derivative is approximated by the difference between two first derivatives. Zero crossings of the second derivative indicating transitions of the input signal may be determined either by detecting a signal peak on both sides of the zero crossing, or by comparing the second derivative signal to zero when the first derivative exceeds a positive or negative threshold. The amount of shift in the zero crossings may be estimated by measuring relative amplitudes or widths of the surrounding signal lobes.

Abstract: A method and apparatus for determining the transitions between binary levels of an input signal such as a scanned bar code label by detecting zero crossings of an approximated second derivative of the input signal. Samples of the input signal are obtained by using delay lines, sample-and-hold circuits, an analog shift register or similar device. The first derivative of the signal is approximated by the slope of a straight line between two sampled points on the waveform. The second derivative is approximated by the difference between two first derivatives. Zero crossings of the second derivative indicating transitions of the input signal may be determined either by detecting a signal peak on both sides of the zero crossing, or by comparing the second derivative signal to zero when the first derivative exceeds a positive or negative threshold. The amount of shift in the zero crossings may be estimated by measuring relative amplitudes or widths of the surrounding signal lobes.

Abstract: An interface selection and configuration system for a computer peripheral in which configuration for the peripheral and/or the host interface is at least in part accomplished by the interface connector cable. In a preferred embodiment, the computer peripheral is equipped with one or more hardware interfaces. The interface connector cable has a first end connector for attaching to the computer peripheral. The first end connector of the interface connector cable is typically a multiple pin connector constructed and arranged to be properly physically and electrically connectable only to a specific computer peripheral or class of computer peripherals, the first end connector including at least one electrical connection between two pins for completing a circuit within the computer peripheral thereby enabling the computer peripheral.

Abstract: Method and apparatus for scanning items with a compact scanner which is mountable onto and/or integral with a pointing instrument. The scanner module may be equipped with an aiming beam for additional help in directing the scan line toward the object to be read. The pointing instrument may be a pen or pencil or alternately a pen-based computer stylus for use with an integrated data terminal module operably connected to the scanner module. Security for preventing separation of the module may be provided by a wireless link.

Abstract: A multiple window data reading device and method for reading symbols such as bar codes through each window, data reading being focused to different focal distances in the scan volume with sensors provided to control focal distance setting from each of the windows.

Abstract: A multi-plane scanner having a dual plane scanner with a horizontal window and a vertical window and a load cell/weigh platter weighing apparatus such that the weigh platter itself is a dual plane object with vertical and horizontal sections. The size and orientation of the planes of the weigh platter correspond to the size and orientation of the scan windows of the dual plane scanner, and each plane of the weigh platter has a transparent area (typically central), or "platter window", corresponding to a respective scan windows of the scanner for allowing transmission of scanned optical beams and optical barcode signals through each of the planes of the weigh platter. The platter is sufficiently rigid to permit accurate weighing whether the object being weighed is placed solely on the horizontal section of the platter or in part on the vertical section. The vertical and horizontal sections of the platter are sealed together to prevent passage of debris therebetween.

Abstract: A method and apparatus for reading bar codes or other images while reducing or eliminating the need for self-generated illumination. An image reader is preferably embodied as a handheld unit and comprises an efficient optical collection system including an aperture with a high aspect ratio and/or a multi-focal lens or lenses. An optically transmissive spacer affixed to the front of the handheld unit allows ambient light to be collected at close range, and a diffuser may be used to reflect ambient light from the handheld unit to provide additional illumination at close range. A masked CCD detector with rectangular pixels receives collected light and is coupled to an adaptive exposure circuit for preventing saturation of the CCD detector at high illumination levels. A correlated double sampling circuit coupled to the adaptive exposure circuit rejects common mode noise and allows operation in lower light levels.

Abstract: A method and apparatus are provided for reading bar codes or other images while reducing or eliminating the need for self-generated illumination. An image reader comprises an efficient optical collection system including an aperture with a high aspect ratio and/or a multi-focal lens or lenses. A CCD detector receives collected light and is coupled to an adaptive exposure circuit for preventing saturation of a CCD detector at high illumination levels. A correlated double sampling circuit receives the output of the CCD detector to allow lower light levels to be detected by the system. The correlated double sampling circuit is connected to a signal processing block which uses a derivative based technique for enhanced edge detection. Edge detection information may be provided to a decoder for decoding. Various other embodiments may utilize some but not all of the above elements, or may include additional refinements, while obtaining the benefit of reducing or eliminating the need for self-generated illumination.

Abstract: A bar code scanning system such as for use in retail checkout having a scanner housing; a plurality of surfaces facing a scan volume from different directions; and sets of pattern mirrors positioned adjacent the respective surfaces, the housing being positioned above the scan volume and containing one or more laser beam modules and/or a scanning mechanism for producing scanning beams which are routed to the pattern mirrors and out through the respective surfaces into the scan volume.

Abstract: An optical system and method for data reading. The preferred system is directed to a scanner which includes a multiple beam source, such as a laser diode and a beam splitter which generates first optical beam and a second optical beam, the first optical beam being directed toward one side of a scanning optical element such as a rotating polygon mirror and to a first mirror array, the second optical beam is being simultaneously directed toward a second optical element such as another side of the rotating polygon mirror and then to a second and a third mirror array. The first mirror array is configured to generate a scan pattern through a vertical window and the second and third mirror arrays are configured to generate scan patterns passing through a horizontal window. In combination, the three mirror arrays generate three sets of scan lines so as to scan the bottom and all lateral sides of an object being passed through the scan volume.

Abstract: An interface selection and configuration system for a computer peripheral in which configuration for the peripheral and/or the host interface is at least in part accomplished by the interface connector cable. In a preferred embodiment, the computer peripheral is equipped with one or more hardware interfaces. The interface connector cable has a first end connector for attaching to the computer peripheral. The first end connector of the interface connector cable is typically a multiple pin connector constructed and arranged to be properly physically and electrically connectable only to a specific computer peripheral or class of computer peripherals, the first end connector including at least one electrical connection between two pins for completing a circuit within the computer peripheral thereby enabling the computer peripheral.

Abstract: An optical system and method for data reading in which a light source generates an optical beam directed toward an object to be read and a variable aperture mechanism positioned in the outgoing light path establishes at least two separate focal planes. The variable aperture device may comprise a variable aperture system in which the size of the aperture is selectively varied about a range within the diffractive limit of the light beam. A preferred aperture mechanism is a liquid crystal aperture with one or more aperture regions which are selectively or consecutively activated. The optical system therefore establishes two or more separate waist locations from a single light source resulting in greater depth of field or multiple depths of field.

Abstract: A point of sale (POS) bar code scanner such as in common use in retail stores includes provision for reading bar coded redemption coupons (or other bar coded documents redeemable for value) in a manner secure from a human operator. Integration of functions between the POS scanner and the coupon reader varies with different embodiments described. Through software associated with bar code decoding logic, a comparison is made between information on a validation coupon and information on items presented for purchase, and a decision is made as to whether the redemption coupon is valid and redeemable in this transaction. In one embodiment, the bar code scanner simply receives the redemption coupon face down on the product scanner window, and integrated decode logic of the scanner identifies the bar code as belonging to a redemption coupon, then makes the comparison and validation of the coupon for the particular transaction.