Patents by Inventor David J. Metcalfe

David J. Metcalfe has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 8004714
    Abstract: A system detects image data in an image data stream that cause ink ejection errors and replaces the image data with a replacement pattern that attenuates the ink ejection errors.
    Type: Grant
    Filed: April 17, 2007
    Date of Patent: August 23, 2011
    Assignee: Xerox Corporation
    Inventors: David J. Metcalfe, Mark R. Parker, Theresa M. Marconi
  • Patent number: 7953288
    Abstract: What is disclosed is a novel system and method for edge transition detection when improve print quality when rendering via high-addressable vector error diffusion in an image processing environment. In order to detect an “ideal” edge and compensate for the adverse effects described in the background hereof, local pixels are detected and local gradient values are calculated and compared against an adjustable threshold to determine the interpolation method needed for that particular pixel. A nearest neighbor interpolation is performed when a local gradient exceeds a predetermined threshold. For example, if the difference between two successive pixels is greater than “200”, nearest-neighbor interpolation is used to calculate the intermediate sub-pixel level(s). Otherwise linear interpolation is used. Dynamically switching between these two interpolation schemes significantly improves the integrity and sharpness of the edges.
    Type: Grant
    Filed: March 18, 2008
    Date of Patent: May 31, 2011
    Assignee: Xerox Corporation
    Inventors: David J. Metcalfe, Yingjun Bai, Xing Li
  • Patent number: 7830554
    Abstract: Defects in an image forming system may give rise to scratched fiducials, missing fiducial regions, or other defects in an image that can run parallel to the process direction. The present disclosure provides for a fiducial compensation method and system for detecting defects thereby allowing spatial tone reproduction curves to be calculated and applied to a digital image in order to eliminate printed streaks due to a photoreceptor's non-uniformities.
    Type: Grant
    Filed: June 29, 2007
    Date of Patent: November 9, 2010
    Assignee: Xerox Corporation
    Inventors: David J. Metcalfe, Terri A. Clingerman, Stuart A. Schweid, Howard Mizes
  • Publication number: 20100100505
    Abstract: A system calculates appropriate billing within an imaging pipeline. An input component receives an image that is described as a plurality of pixels. A PDL component receives the image and determines a location, a color and a designation for each of the one or more pixels. A marking engine modifies the one or more pixels based at least in part on the location and the color provided by the PDL component and places each of the one or more pixels as a monochrome or a composite pixel on a substrate. An analysis component counts the number of monochrome and composite pixels placed on the substrate by the marking engine, the number of composite pixels that include a designation are counted as monochrome. A billing component calculates the cost for placing each of the monochrome and the composite pixels counted by the analysis component.
    Type: Application
    Filed: October 16, 2008
    Publication date: April 22, 2010
    Applicant: XEROX CORPORATION
    Inventors: James B. Campbell, Francis Kapo Tse, Xing Li, David J. Metcalfe
  • Publication number: 20090238489
    Abstract: What is disclosed is a novel system and method for edge transition detection when improve print quality when rendering via high-addressable vector error diffusion in an image processing environment. In order to detect an “ideal” edge and compensate for the adverse effects described in the background hereof, local pixels are detected and local gradient values are calculated and compared against an adjustable threshold to determine the interpolation method needed for that particular pixel. A nearest neighbor interpolation is performed when a local gradient exceeds a predetermined threshold. For example, if the difference between two successive pixels is greater than “200”, nearest-neighbor interpolation is used to calculate the intermediate sub-pixel level(s). Otherwise linear interpolation is used. Dynamically switching between these two interpolation schemes significantly improves the integrity and sharpness of the edges.
    Type: Application
    Filed: March 18, 2008
    Publication date: September 24, 2009
    Applicant: Xerox Corporation
    Inventors: David J. METCALFE, Yingjun BAI, Xing LI
  • Publication number: 20090003729
    Abstract: Defects in an image forming system may give rise to scratched fiducials, missing fiducial regions, or other defects in an image that can run parallel to the process direction. The present disclosure provides for a fiducial compensation method and system for detecting defects thereby allowing spatial tone reproduction curves to be calculated and applied to a digital image in order to eliminate printed streaks due to a photoreceptor's non-uniformities.
    Type: Application
    Filed: June 29, 2007
    Publication date: January 1, 2009
    Inventors: David J. Metcalfe, Terri A. Clingerman, Stuart A. Schweid, Howard Mizes
  • Publication number: 20080260263
    Abstract: A system detects image data in an image data stream that cause ink ejection errors and replaces the image data with a replacement pattern that attenuates the ink ejection errors.
    Type: Application
    Filed: April 17, 2007
    Publication date: October 23, 2008
    Applicant: Xerox Corporation
    Inventors: David J. Metcalfe, Mark R. Parker, Theresa M. Marconi
  • Patent number: 7277191
    Abstract: A method and apparatus are provided for the processing of an image, such as a document. The invention determines the location of differing content types within the document allowing specialized processing of various content types. The invention performs the identification of pixels having similar content characteristics into windows during the first scanning pass of the document by the use of an identifier equivalence table to update selected memory locations to a base identifier during processing. A second pass processing is available to enhance or alter the image by the use of the information gathered during first pass processing. The present invention benefits from a very low memory requirement while being able to determine windows extending the length or width of the image.
    Type: Grant
    Filed: June 27, 2001
    Date of Patent: October 2, 2007
    Assignee: Xerox Corporation
    Inventors: David J. Metcalfe, Jeng-nan Shiau
  • Patent number: 6603575
    Abstract: A system and method for processing image data converts a pixel of image data having a first resolution to a plurality of subpixels, the plurality of subpixels representing a second resolution, the second resolution being higher than the first resolution. The plurality of subpixels are thresholded to generate a group of subpixel values for each pixel and a threshold error value. It is then determined if the group of subpixel values from the thresholding process produce a pattern containing an isolated subpixel. If the group of subpixel values from the thresholding process produce a pattern containing an isolated subpixel, the group of subpixel vales is modified to produce a pattern without an isolated subpixel. The modification process produces a subpixel error value which is compensated for localized error before being diffused to adjacent pixels.
    Type: Grant
    Filed: January 16, 2002
    Date of Patent: August 5, 2003
    Assignee: Xerox Corporation
    Inventors: Stuart A. Schweid, David J. Metcalfe
  • Patent number: 6594401
    Abstract: A first aspect of the present invention is a process for masking a scanning artifact within image data representing a document. The process includes generating pixel classification tags for the image data; identifying a window within the image data associated with a scanning artifact using the pixel classification tags; analyzing the image data to derive a replacement video value; and replacing image data associated with a scanning artifact with the replacement video value.
    Type: Grant
    Filed: October 20, 1999
    Date of Patent: July 15, 2003
    Assignee: Xerox Corporation
    Inventors: David J. Metcalfe, Leon C. Williams, Roger L. Triplett
  • Publication number: 20030002087
    Abstract: A method and apparatus are provided for the processing of an image, such as a document. The invention determines the location of differing content types within the document allowing specialized processing of various content types. The invention performs the identification of pixels having similar content characteristics into windows during the first scanning pass of the document by the use of an identifier equivalence table to update selected memory locations to a base identifier during processing. A second pass processing is available to enhance or alter the image by the use of the information gathered during first pass processing. The present invention benefits from a very low memory requirement while being able to determine windows extending the length or width of the image.
    Type: Application
    Filed: June 27, 2001
    Publication date: January 2, 2003
    Applicant: Xerox Corporation
    Inventors: David J. Metcalfe, Jeng-nan Shiau
  • Patent number: 6449061
    Abstract: A process eliminates pattern shifting artifacts in a printed image rendered using a hybrid high addressable error diffusion process by perturbing a threshold/image signal value relationship when a multi-level grey level is binarized. The process utilizes a programmable multi-level grey signal modifying circuit for modifying the multi-level grey signal by a predetermined value according to its grey level. The modified multi-level grey signal is binarized to a binary pixel signal according to a relationship between the modified multi-level grey signal and a threshold value. The process further generates an error corresponding to the relationship and diffuses the error to neighboring pixels. The multi-level grey signal is modified with either random noise multiplied by a grey level dependent coefficient value. The coefficient value is dependent upon an image classification of the pixel being processed.
    Type: Grant
    Filed: April 20, 1998
    Date of Patent: September 10, 2002
    Assignee: Xerox Corporation
    Inventor: David J. Metcalfe
  • Patent number: 6427030
    Abstract: A method and system implements a dynamic error diffusion process. A grey level value representing a pixel is received. An image segmentation circuit determines an image characteristic of the pixel being processed. A threshold circuit thresholds the grey level value (pixel) and generates an error value as a result of the threshold process. A portion of the error value is diffused to adjacent pixels on a next scanline. The distribution of this error value is dynamic in that different sets of weighting coefficients are used based the image characteristic of the processed pixel. One set of coefficients are utilized in processing a pixel having a first image characteristic, and a second set of coefficients are utilized in processing a pixel having a second image characteristic.
    Type: Grant
    Filed: August 3, 1994
    Date of Patent: July 30, 2002
    Assignee: Xerox Corporation
    Inventors: Leon C. Williams, Jeng-Nan Shiau, David J. Metcalfe
  • Publication number: 20020097438
    Abstract: A system and method for processing image data converts a pixel of image data having a first resolution to a plurality of subpixels, the plurality of subpixels representing a second resolution, the second resolution being higher than the first resolution. The plurality of subpixels are thresholded to generate a group of subpixel values for each pixel and a threshold error value. It is then determined if the group of subpixel values from the thresholding process produce a pattern containing an isolated subpixel. If the group of subpixel values from the thresholding process produce a pattern containing an isolated subpixel, the group of subpixel vales is modified to produce a pattern without an isolated subpixel. The modification process produces a subpixel error value which is compensated for localized error before being diffused to adjacent pixels.
    Type: Application
    Filed: January 16, 2002
    Publication date: July 25, 2002
    Applicant: Xerox Corporation
    Inventors: Stuart A. Schweid, David J. Metcalfe
  • Patent number: 6351319
    Abstract: A system and method for processing image data converts a pixel of image data having a first resolution to a plurality of subpixels, the plurality of subpixels representing a second resolution, the second resolution being higher than the first resolution. The plurality of subpixels are thresholded to generate a group of subpixel values for each pixel and a threshold error value. It is then determined if the group of subpixel values from the thresholding process produce a pattern containing an isolated subpixel. If the group of subpixel values from the thresholding process produce a pattern containing an isolated subpixel, the group of subpixel vales is modified to produce a pattern without an isolated subpixel. The modification process produces a subpixel error value which is compensated for localized error before being diffused to adjacent pixels.
    Type: Grant
    Filed: December 18, 1998
    Date of Patent: February 26, 2002
    Assignee: Xerox Corporation
    Inventors: Stuart A. Schweid, David J. Metcalfe
  • Patent number: 6347159
    Abstract: A method and system implements screening and a high addressability characteristic into an error diffusion process. A grey level value representing a pixel is received. The grey level value has a first resolution which corresponds to an original input resolution. The grey level value is then screened. A threshold circuit thresholds the grey level value and generates an error value as a result of the threshold. A portion of the error value is diffused to adjacent pixels on a next scanline. The screened grey level value can also be interpolated to generate subpixel grey level values which correspond to a second resolution. The second resolution is higher than the first resolution and corresponds to the high addressability characteristic. The threshold circuit would then threshold the grey level value and generate an error value having a resolution corresponding to the first resolution.
    Type: Grant
    Filed: August 3, 1994
    Date of Patent: February 12, 2002
    Assignee: Xerox Corporation
    Inventors: Leon C. Williams, Jeng-Nan Shiau, David J. Metcalfe
  • Publication number: 20010015816
    Abstract: A process eliminates pattern shifting artifacts in a printed image rendered using a hybrid high addressable error diffusion process by perturbing a threshold/image signal value relationship when a multi-level grey level is binarized. The process utilizes a programmable multi-level grey signal modifying circuit for modifying the multi-level grey signal by a predetermined value according to its grey level. The modified multi-level grey signal is binarized to a binary pixel signal according to a relationship between the modified multi-level grey signal and a threshold value. The process further generates an error corresponding to the relationship and diffuses the error to neighboring pixels. The multi-level grey signal is modified with either random noise multiplied by a grey level dependent coefficient value. The coefficient value is dependent upon an image classification of the pixel being processed.
    Type: Application
    Filed: April 20, 1998
    Publication date: August 23, 2001
    Inventor: DAVID J. METCALFE
  • Patent number: 6266438
    Abstract: A color space transformation device includes a sensor bar. The sensor bar includes a plurality of sensor chips. Each sensor chip scans a unique section of an original image to produce first data in a first color space. A memory means stores groups of coefficients. Each group of coefficients corresponds to one of the sensor chips. A processor independently transforms each of the sections of the first data to a respective section of a second data. The transformation is performed as a function of one of the groups of coefficients corresponding to the sensor chip which produced the first data.
    Type: Grant
    Filed: September 28, 1998
    Date of Patent: July 24, 2001
    Assignee: Xerox Corporation
    Inventors: David J. Metcalfe, Dawn M. Williams-Fuller, Joseph P. Taillie, Josef E. Jedlicka
  • Patent number: 6249357
    Abstract: A high addressable hybrid error diffusion process adds an error value to an input grey image value to produce a modified input grey image value before comparing the modified input grey image value with a predetermined threshold value. A rendering value and error is generated based on the comparison. The error is equal to n(GL/N)*Aeff, wherein n is equal to the number of subpixels turned ON, GL is the maximum grey value for a pixel, N is the addressability of the rendering system, and Aeff is an effective spot area value for the rendering system. The effective spot area value is retrieved from a look-up table having a plurality of effective spot area values based on the input grey image value.
    Type: Grant
    Filed: May 30, 1996
    Date of Patent: June 19, 2001
    Assignee: Xerox Corporation
    Inventors: David J. Metcalfe, Jeng-Nan Shiau
  • Patent number: 6233360
    Abstract: A method and system implements a high addressability characteristic into an error diffusion process. A histogram of the image is generated and the actual background and black reference values are determined. A gray level value representing a pixel is received. The gray level value has a first resolution which corresponds to an original input resolution. The gray level value is interpolated to generate subpixel gray level values which correspond to a second resolution. The second resolution is higher than the first resolution and corresponds to the high addressability characteristic. A threshold circuit thresholds the interpolated gray level value and generates an error value as a result of the threshold using the determined background and black reference values. The error value has a resolution corresponding to the first resolution. A portion of the error value is diffused to adjacent pixels on a next scanline.
    Type: Grant
    Filed: September 24, 1996
    Date of Patent: May 15, 2001
    Assignee: Xerox Corporation
    Inventors: David J. Metcalfe, Roger L. Triplett, Xiao-fan Feng, John T. Newell