Abstract: There is described an imaging apparatus having an imaging assembly that includes an image sensor. The imaging apparatus can capture a frame of image data having image data corresponding to a first set of pixels of the image sensor. The imaging apparatus can capture a frame or image data having image data corresponding to a second set of pixels of the image sensor.

Abstract: A reader for electro-optically reading a target in the presence of ambient light to be suppressed, includes a laser for emitting a laser beam, a scan component for scanning the laser beam across the target, a photodetector for detecting return laser light from the target to generate an information signal bearing information related to the target, and for concomitantly detecting the ambient light to generate an ambient light signal, and signal processing circuitry for measuring the ambient light signal, for processing both the information signal and the ambient light signal in one mode of operation when the measured ambient light signal is below a threshold, and for suppressing the ambient light signal and for processing only the information signal in another mode of operation when the measured ambient light signal at least equals the threshold.

Abstract: A reader for electro-optically reading a target in the presence of ambient light, includes a scan component for scanning a laser beam across the target, a first filter for passing return laser light from the target and the ambient light to a first photodetector system for generating a first output signal constituted of an information signal and a first ambient light signal, a second filter for passing the ambient light to a second photodetector system for generating a second output signal constituted of a second ambient light signal, and signal processing circuitry for measuring a difference between the first and second ambient light signals, for equalizing the first and second ambient light signals when the difference exceeds a threshold, and for subtracting the second output signal from the first output signal to obtain a receiver output signal substantially constituted only of the information signal.

Abstract: A method for noise removal from color barcode images includes acquiring a barcode image using a color imaging array and separating the barcode image into color channels. Weighting factors are associated with the color channels and at least one weighting factor is reduced. The weighting factors are applied to the color channels to produce a first transformed image. A portion of the first transformed image is analyzed to produce a first set of decoded data from the barcode.

Abstract: A system and method of scanning machine-readable symbols with a signal source modulated by a local oscillator to create by heterodyne mixing upconverted signals at the sum and difference frequencies of the local oscillator frequency and the frequency of the time-varying reflectance off the scanned symbols is disclosed. The reflected heterodyned signal is detected by a receiver. Ambient noise is filtered out from the reflected signal, and the received signal at the sum and difference frequencies is processed.

Abstract: An imager in an imaging reader captures light from a target, generates image data from the captured light, and generates a pixel clock signal having a pixel clock frequency in synchronism with the image data. A controller is connected via an electrical conductor to the imager, and controls the imager to transfer the image data, receives the image data, and processes the image data. A circuit suppresses electromagnetic radiation generated by the conductor during the image data transfer, and includes a spread spectrum modulator for modulating the pixel clock signal to generate a variable spread spectrum signal having a spread spectrum frequency that periodically varies above and below the pixel clock frequency, and a buffer having a plurality of registers for receiving and temporarily storing the image data, and for varying as a function of the spread spectrum frequency how much of the image data is being temporarily stored.

Abstract: A bar-code reading apparatus includes a differential processor which generates a differential signal from an electric signal corresponding to an intensity of light reflected from a bar code, an extreme value detector which detects each extreme value of the differential signal and generates extreme value information including at least an electric signal value of the detected extreme value, a voltage difference calculator which calculates a voltage difference in electric signal between a target extreme value and at least one of extreme values adjacent thereto for each extreme value in the extreme value information, and an extreme value verifying unit which compares the voltage difference with a predetermined threshold value and determines the validity of the extreme value corresponding to the voltage difference for each voltage difference. Information encoded as the bar code is decoded by using extreme value information of the valid extreme value.

Abstract: A method for processing a digital signal obtained in a barcode reading operation comprises a step of applying a wavelet transformation to the digital signal. The noise threshold at each level of the wavelet transformation is determined from a total transfer function in the analogue processing stage, and the coefficients are set to be zero if less than the noise threshold.

Abstract: Systems and techniques for using signal to noise ratio information to enhance bar code scanning accuracy. Noise information affecting bar code scanning operations is stored and a scan signal is monitored. Upon detection of a scan of a bar code, the signal strength of the scan signal is evaluated and signal to noise ratio values are computed. Signal to noise ratio information is used to favor or disfavor candidate decoding results. In addition, signal to noise ratio thresholds are set according to appropriate criteria. Decoding results are evaluated using the signal to noise ratio thresholds and accepted or rejected depending on whether the thresholds are met. In addition, thresholds for recognition of transitions based on peaks may be set based on expected noise affecting the scan signal, and allowed or excluded based on whether a rise from a negative peak, or fall from a positive peak, meets the threshold.

Abstract: Systems and techniques for eliminating or compensating for noise affecting a bar code scanner. A scanner is operated in a learning mode under conditions designed to insure that a scan signal will take on predictable characteristics and noise affecting the scan signal will be easily detectable. During the learning mode, information relating to noise affecting the scan signal and the conditions under which the noise occurs is stored. During normal operation of the scanner, the stored noise information is used in controlling operation of the scanner so as to eliminate or compensate for noise under conditions in which noise has been shown to be susceptible to occur.

Abstract: A scanning device includes a laser source emitting a laser scanning beam, a movable scanning mirror reflecting the laser scanning beam towards an on object to be scanned, a mirror moving element moving the movable scanning mirror and a controller receiving an input corresponding to a range estimate from the scanning device to the object and adjusting a setting of the scanning device based on the range estimate.

Abstract: An imaging-based bar code reader that includes an imaging and decoding system. When used on a stand to image documents, typically neither the stand or document is moving. Therefore blurring due to motion is not an issue. A sensor detects when the scanner is mounted to a stand. When commanded to take an image the scanner electronics and software modifies an auto-exposure process to minimize gain and lengthen exposure. This modification results in the scanner that is effective for scanning bar codes and yet also takes excellent pictures when mounted to a stand.

Abstract: A linear sensor array for imaging coded indicia includes an analog front end and a digital back end integrated on a single CMOS chip. A real-time, correlated double sampling circuit is used for noise suppression.

Abstract: A barcode sensor package has an optical emitter circuit and an optical detector circuit which are formed as one or more integrated optical circuits disposed in a housing which has a reading surface and one or more apertures located between the optical emitter and detector circuits. The optical emitter circuit has an emitter die, such as a vertical cavity surface emitting laser (VCSEL), for emitting a light beam and a diffraction optical element disposed on the emitter die for focusing the light beam to a bar code. The optical detector circuit has a photodetector die, such as a phototransistor, for detecting reflective light and another diffraction optical element disposed on the photodetector die for guiding light reflected from the bar code to the detector. The diffraction optical elements are fabricated by patterning optical layers, deposited on respective emitter and detector dies, using photolithograph or a direct write process.

Abstract: An image input system includes a solid state image pickup device and a preprocessor for performing correlated double sampling amplification on an output of the image pickup device and outputting a video signal. The preprocessor has a correlated double sampling amplifier for outputting signal information corresponding to a difference voltage between the black level in a feedthrough period of the image pickup device and a signal level in a charge signal output period; and an offset cancelling circuit for cancelling an offset voltage corresponding to the difference voltage in a state where the image pickup device is optically interrupted to the input terminal of the correlated double sampling amplifier. The correlated double sampling amplifier cancels out the offset voltage and the offset cancelling voltage as signal components of polarities opposite to each other, so that circuits following the correlated double sampling amplifier are not influenced by the offset voltage.

Abstract: A low pass filter that approximates a Gaussian transfer function filters the analog bar code signal prior to digitization is used to smooth the bar code signal. The Gaussian filter has a transfer function that compensates for beam distortion close in to the bar code scanner. The smoothed bar code signal is provided to the digitizer to improve the efficiency with which the bar code signal can be digitized.

Abstract: A scanning device or alight beam is moved for reciprocal scanning with respect to an image carrier, which carries image information thereon, and in a main scanning direction. The scanning device or the light beam is also moved with respect to the image carrier and in a sub-scanning direction intersecting with the main scanning direction. Light, which comes from the image carrier, is photoelectrically converted into an electric image signal. Smoothing operation processing is performed on forward scanning image signal components and backward scanning image signal components, which have been acquired respectively in a forward scanning stage and a backward scanning stage consecutive in the reciprocal scanning, and with respect to the sub-scanning direction.

Abstract: A signal obtained by optically scanning a bar code is subjected to differentiation to obtain differential data. Peak-to-peak distances are calculated from the differential data. When a peak-to-peak ?Tx distance is y times of a basic width, frequency f(x,y) will be, f(x,y)=y/?Tx. A frequency map is prepared from the frequencies calculated. Transition routes in which one frequency each is selected. from each of the peak-to-peak distances, are formed. A transition route for which an error in frequencies is the least is taken as the most suitable transition route. An average of the frequencies included in the transition route is taken as a frequency f0 of the basic width.

Abstract: A planar light illumination and imaging system for illuminating an object and forming an image thereof. The planar light illumination and imaging system which comprises an image formation and detection module having a field of view (FOV) focused at an image detecting array. A planar light illumination array (PLIA) constructed from an plurality of planar light illumination modules (PLIMs) is arranged in rectilinear manner.

Abstract: A system and method to binarize the bar code image in the presence of noise in order to render bar codes more detectable in the presence of noise. The method of this invention includes the steps of applying a gradient detecting filter to the bar code image, obtaining a filtered image, and then, adaptively binarizing the bar code image utilizing the corresponding filtered image to obtain an adaptive threshold. A system that implements the method is also described.

Abstract: An optical information reading apparatus applies light to an object to be read such as a bar code symbol, photoelectrically converts by a photodetector element a light image formed by the reflection light, and processes the obtained electric signal to output code data. Among the portions performing the signal processing, at least a data converter (13) for converting a photoelectrically converted electric signal into a digital signal, a digital signal calculation unit (17) for calculating the digital signal and generating code data indicating information of an object to be read, an input accumulation unit (20) for accumulating the code data, and a timing control unit (12) for controlling operation timings of these components are arranged on a single substrate as a multipurpose processing circuit block (10).

Abstract: Signal processing performance in electro-optical readers is improved by changing filter characteristics and/or digitizer thresholds during successive scans.

Abstract: The method for compensating undesired variations in an electrical signal generated by a sensor of an optical code reader comprises the steps of generating an envelope signal starting from the electrical signal generated by the sensor and normalizing the electrical signal with respect to the envelope signal. Preferably, the envelope signal is filtered with a low-pass filter before being normalized so as to eliminate steps and edges which may cause distortions during normalization, and the normalized signal is amplified in a controlled way so as to supply an output signal ranging between two values having preset amplitudes. Normalization is carried out by dividing, point by point, the electrical signal by the envelope signal, in the case of continuous analog processing; alternatively, in presence of discrete-time signals, normalization is carried out by subtracting the envelope signal from the electrical signal.

Abstract: An image input system includes a solid state image pickup device and a preprocessor for performing correlated double sampling amplification on an output of the image pickup device and outputting a video signal. The preprocessor has a correlated double sampling amplifier for outputting signal information corresponding to a difference voltage between the black level in a feedthrough period of the image pickup device and a signal level in a charge signal output period; and an offset cancelling circuit for cancelling an offset voltage corresponding to the difference voltage in a state where the image pickup device is optically interrupted to the input terminal of the correlated double sampling amplifier. The correlated double sampling amplifier cancels out the offset voltage and the offset cancelling voltage as signal components of polarities opposite to each other, so that circuits following the correlated double sampling amplifier are not influenced by the offset voltage.

Abstract: A method for operating a code reader and a code reader. According to the method, laser light is transmitted from a laser light source to illuminate an object having a code, wherein the laser light is amplitude-modulated to reduce the speckle noise of the light illuminating the object. Reflected or re-emitted light from the object is received by a light receiver. According to the code reader, the code reader includes a light transmitter having a laser light source adapted for transmitting laser light to illuminate an object having a code. The code reader also includes a light receiver arranged for receiving reflected or re-emitted light from the object and for producing electrical signals corresponding to the received light. The code reader also includes a modulation apparatus that modulates the laser light source such that amplitude-modulated light can be transmitted from the laser light source to the object.

Abstract: A planar laser illumination and imaging (PLIIM) based system employing wavefront control methods for reducing the power of speckle-pattern noise within digital images acquired by the system. The system comprises a housing having a first light transmission aperture, a second light transmission aperture, and a third light transmission aperture, wherein the first and second light transmission apertures are optically isolated from said third light transmission aperture spatially aligned on opposite sides thereof. A pair of planar laser illumination arrays (PLIAs) are mounted within the housing, for producing and projecting a first and second planar laser illumination beams (PLIBS) through the first and second light transmission apertures respectively, thereby producing a composite planar laser illumination beam (PLIB) outside of the housing, and illuminating an object therewith as the object is transported past the first, second and third light transmission apertures.

Abstract: Various techniques for reducing the size of bar code scanner modules are disclosed including embodiments having miniature moving mirror elements employing spiral tape springs and micro machined structures. Other embodiments employ VCSELs and relatively small collection areas, while minimizing speckle noise through beam shaping and signal processing techniques.

Abstract: The effects of paper/substrate noise are significantly reduced in multi-focal zone laser scanning systems by processing analog scan data signals with a scan data signal processor having a plurality of pass-band filters and amplifiers that are automatically selected for passing only the spectral components of an analog scan data signal produced when a bar code symbol is scanned at a particular focal zone in the laser scanning system. Two or more different pass-band filter structures can be provided for use in the scan data signal processor, wherein each pass-band filter structure is tuned to the spectral band associated with a particular focal zone in the laser scanning system. When a bar code symbol is scanned by a laser beam focused within the first focal zone or scanning range of the system, the pass-band filter structure associated with this focal zone or scanning range is automatically switched into operation.

Abstract: A dual channel video data recovery system for use in a bar code scanner. A first and a second video signal are generated in parallel in response to light reflected from a bar code. The first and second video signals are received and filtered to limit their frequency ranges and produce filtered first and second video signals. The first and second filtered video signals are limited to different and preferably coverlapping frequency ranges. The first and second video signals have differing thresholds which may be dynamically varied. The first and second filtered video signals are converted to first and second digital data strings. If both strings contain useful data, the string containing the higher-quality data is decoded to recover bar code information. If only one string contains useful data, the string containing useful data is decoded.