Abstract:
To reduce errors introduced by a scanner, an unmarked, digital master document may be generated and stored in digital form so that subsequent scanning of the document is unnecessary to place it in digital form for comparison to a marked version of the document. Additionally, regions or fields, rather than the entire digital master document, may be individually created, stored, and subsequently used for comparison to corresponding portions of a marked version. Further, test targets or patterns may be inserted into the content of a digital master document. Characteristics of image quality degeneration and distortion can be extracted from printed versions of the test targets or patterns and used to effect closed loop control to digitally reduce image quality degeneration caused by the scanner.
Abstract:
Disclosed are a method and a computer program product for dissipating heat produced in a scan head assembly of an imaging apparatus during scanning of media sheets in the imaging apparatus. The method includes determining at least one of a temperature of the scan head assembly and a media sheet scan count. The method further includes moving the scan head assembly between a first position of the scan head assembly and a second position of the scan head assembly for dissipating heat, based on at least one of the temperature of the scan head assembly and the media sheet scan count.
Abstract:
A scan module including an image sensor defining a scan field, at least one lamp positioned to illuminate at least a portion of the scan field, and a second light source positioned to provide illumination for the portion of the scan field.
Abstract:
A scanner calibration strip medium is described which includes at least one of a plurality of text symbols and a plurality of halftoned non-text images. A scanner is described which includes a scan bar and a scanner calibration strip medium scannable by the scan bar. The calibration strip medium includes a plurality of text symbols having text pixels and a plurality of halftoned non-text images having halftoned non-text pixels. A method for segmenting a scanned document image into text symbols and halftoned non-text images is described which uses a scanner calibration strip medium which includes a plurality of text symbols having text pixels and a plurality of halftoned non-text symbols having halftoned non-text pixels, wherein the calibration strip medium has a known pixel classification including which pixels of the calibration strip medium are text pixels and which pixels of the calibration strip medium are halftoned non-text pixels.
Abstract:
A method for adjusting a controller of a scanner includes obtaining a scan of a predefined image. The method further includes moving the sensor-element signals of the control signal pattern generated by the controller earlier in the pattern by at least one unit and obtaining an additional scan. The obtaining and moving are repeated until a comparison of a latest additional scan to the image is worse than a comparison of a second-latest additional scan to the image. Another method obtains a noise-reducing heuristic which modifies a time parameter of a sensor-element signal. A set of repeated scans of a same scan line is obtained, noise is measured there from, the time parameter is modified by one predetermined unit, and the process repeats until the noise measured from the latest set of repeated scans is worse than that from the second-latest set of repeated scans.
Abstract:
A method is provided for compensating two-dimensional images for non-uniformity variations in the illumination of a document, or a scene, that is acquired by a digital camera. The invention can include a printer and/or a personal computer to perform some or all of the compensation calculations, if desired. The present invention captures initial image data, determines a region or area of that data having substantially, or somewhat, uniform pixel intensities and uses that as a background or border region. This border data is used to calculate correction data to correct or compensate the non-border pixel values for non-uniformities in the illumination of the image when it was first acquired, without needing a separate reference frame.
Abstract:
Methods of identifying the location and dimensions of a contaminant particle on a calibration strip may be used to compensate for contaminant particles on a calibration strip. A method of locating a contaminant particle on a calibration strip comprises imaging a calibration strip comprising a plurality of channels arranged in rows and a plurality of pixel columns, wherein each channel comprises a plurality of horizontally adjacent pixels, and each pixel column comprises pixels from a plurality of channels. The method also includes generating an average pixel intensity value by normalizing the channels and locating a contaminant particle in a pixel column by comparing the intensity of an individual pixel in the pixel column to the average pixel intensity value. An intensity value of an individual pixel less than a predefined limit set below the normalized local average pixel intensity value corresponds to a location of a contaminant particle. The method further includes identifying the number of adjacent pixels in a pixel column less than a predefined limit set below the normalized local average pixel intensity value.
Abstract:
A gamut mapping algorithm especially adapted for printing business and presentation graphics with highly chromatic colors. To perform gamut mapping, gamut triangles corresponding to an input gamut and output gamut are defined and used to scale the lightness and chroma of input colors. The rescaled input colors are then mapped to the output triangle along lines of constant chroma. The chroma of the remapped colors is enhanced by moving the remapped colors toward the apex of the output gamut triangle along a line passing through the remapped color and the apex of the output gamut triangle.
Abstract:
An illumination assembly for a scanner comprising a light source, a primary reflector and a secondary reflector. The primary reflector comprises a lower member and upper member spaced away from the lower member. The upper member has a heatsink for dissipating the heat of the light source. The light source is positioned between the lower and upper members and is attached to the upper member allowing for decreased vertical height for the illumination assembly.
Abstract:
Method and image scanning apparatus comprising an image capture unit having an illumination assembly for generating input light; a printed circuit board mounted to the image capture unit, a cooling unit generating an airflow which cools the illumination assembly of the image capture unit as well as the critical components mounted on the printed circuit board and the optical components of the image capture unit; and an adjustable baffle member moveably mounted to the frame of the image scanning apparatus for controlling the path of the airflow relative to the lamp. The cooling unit comprises at least one fan with the fan generating airflow for cooling the lamp of image capture unit. The baffle member is adjustable to control the airflow generated by the fan such that the airflow generated by the fan is redirected downward and passes the airflow under the image capture unit, thereby effectively and evenly cooling the lamp and redirecting contaminants to the end of the image scanning apparatus enclosure opposite the image capture unit.