Abstract: In a full-color image scanner having three parallel linear arrays of photosensors, each linear array of photosensors is sensitive to one primary color. With each readout cycle relating to a row of small areas on an original image moving past the scanner, the middle array of the three arrays of photosensors reads out its video data before the other two. This technique allows the arrays of photosensors to be spaced relatively close to each other, and in turn the close spacing of photosensors requires relatively fewer scan lines of video data to be temporarily buffered in the readout process.

Abstract: A system and method suppresses automatically a background of a document being scanned. A histogram circuit generates a histogram from a predetermined group of scanlines of image data collected at a lead edge of the document being scanned, and a gain correction circuit calculates a gain value from the histogram and applies the gain to the image data. The histogram circuit generates a next histogram from a next predetermined group of scanlines of image data collected from the document being scanned. The gain correction circuit then calculates a next gain value from the next histogram. A comparator enables the application of the next gain value to the image data if the next gain value is less than a previously calculated gain value.

Abstract: In a full-color image scanner having three parallel linear arrays of photosensors, each linear array of photosensors is sensitive to one primary color. With each readout cycle relating to a row of small areas on an original image moving past the scanner, the middle array of the three arrays of photosensors reads out its video data before the other two. This technique allows the arrays of photosensors to be spaced relatively close to each other, and in turn the close spacing of photosensors requires relatively fewer scan lines of video data to be temporarily buffered in the readout process.

Abstract: The present invention is a method of compensating for the offset present in image signals produced by an image processing apparatus, and more particularly to accurately characterizing the offset, gain and higher order responses of image sensing elements to enable correction thereof in an image sensing device or scanner. The method utilizes intermediate (grey) reflectance targets to measure the response of each sensor element and then, using the measured responses, fits a characteristic curve to the responses to calculate the response of the sensor element, including a zero reflectance situation, to characterize an accurate offset level, gain, and higher order response for the sensor. Moreover, additional reflectance targets and response may be employed so as to enable the characterization of image sensing elements exhibiting non-linear responses to linearly increasing light intensities.

Abstract: A system and method electronically image process a pixel belonging to a set of digital image data with respect to a membership of the pixel in a plurality of image classes. This process uses classification to determine a membership value for the pixel for each image classes and generates an effect tag for the pixel based on the fuzzy classification determination. The pixel is image processed based on the membership vector of the pixel. The image processing may include screening and filtering. The screening process screens the pixel by generating a screen value according to a position of the pixel in the set of digital image data; generating a screen amplitude weighting value based on the values in the membership vector for the pixel; multiplying the screen value and the screen amplitude weighting value to produce a modified screen value; and adding the modified screen value to the pixel of image data.

Abstract: In a digital imaging document handling system for sequentially feeding plural document sheets in a document feeding path from a document input to an electronic imaging station, wherein document sheet feeding stoppages in the document feeding path are detectable, a simplified job recovery system is provided by providing a duplicate image detection system for the automatic deletion of duplicate electronic document page images. The duplicate page images may be detected efficiently without full image comparisons by checksumming the pixels of multiple cell areas for the page, deleting the least significant figures, and comparing the respective cell checksums.

Abstract: In a color scanner wherein a plurality of filters are selectably disposed in a light path to a sensor array, a target area of a preselected test color is provided adjacent the platen for the image to be scanned. The target area is used to determine which of the plurality of filters is disposed along the light path at a given time.

Abstract: An asynchronous document scanner with one dimensional scanning array, a movable scan carriage supporting the array for scanning movement, a variable interpolator for interpolating partial lines of image signals from the array with preceding lines of image signals to provide a composite image signal lines, and a control responsive to the timing of the start integration signal to the array to vary the interpolation coefficient of the interpolator.

Abstract: Process and apparatus for allowing a raster input scanner with scanning array to operate asynchronously in which timing of the fixed rate shift pulses which delineate the integration period of the array is changed to maintain the shift pulses in timed synchronization with a random integration signal.

Abstract: A system for self-aligning a raster input scanner in the slow scan direction where, at start of scan, a target having a variable density image is scanned first until a preset target image line is obtained and the position of the scan carriage registered; then from the registered position, the platen is scanned through a predetermined number of scan lines; following this, the carriage is reversed and returned the same number of scan lines where the target is again scanned and the target image line obtained compared with the previous target image line to determined if a valid scan cycle has taken place.

Abstract: Scan lamp intensity control with reflective patch scanned along with each image line, the reflectance signals obtained being later separated from the image signals and compared to a desired intensity level adjusted to the D/A current reference voltage. To maintain operation within the range of photosite offset adjustment, a scan lamp intensity setpoint is obtained at the beginning of scan.