Patents by Inventor Raja Bala

Raja Bala 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).

  • Publication number: 20100182649
    Abstract: A model-based halftone independent method for characterizing a printer equipped with a plural of halftone screens comprises: printing a target set of basic patches comprised of a fundamental binary pattern independent of a halftone screen; measuring true color printer response from the target set; modeling a halftone independent characterization of the printer with the mathematical transformation using the measured response; modeling a first halftone dependent characterization of the printer with the mathematical transformer to generate a first predicted result using a selected halftone screen; comparing a measured response of the printer using the halftone screen with the predicted result to define a correction factor corresponding to the halftone screen; and modeling a halftone dependent characterization of the printer using a predicted response of the fundamental binary pattern and the correction factor.
    Type: Application
    Filed: January 21, 2009
    Publication date: July 22, 2010
    Applicant: Xerox Corporation
    Inventors: Vishal Monga, Shen-Ge Wang, Raja Bala
  • Patent number: 7760934
    Abstract: A method and apparatus for translating color to grayscale images, wherein at least some pixels of the color image having the same color are mapped to different grays in the grayscale image depending on the spatial surround of each pixel. Further, the method and apparatus may include applying a high pass filter to at least one chrominance component of a color image to generate at least one high pass filtered chrominance component, and adjusting a luminance component of the color image based upon the at least one high pass filtered chrominance component.
    Type: Grant
    Filed: March 28, 2008
    Date of Patent: July 20, 2010
    Assignee: Xerox Corporation
    Inventors: Raja Bala, Reiner Eschbach
  • Patent number: 7747073
    Abstract: A system and method for generating an adjusted profile for a device in response to a specified aim, where the aim may include parameters established in response to a user's specifications, for device emulation, etc.
    Type: Grant
    Filed: November 24, 2004
    Date of Patent: June 29, 2010
    Assignee: Xerox Corporation
    Inventors: Raja Bala, Gaurav Sharma
  • Publication number: 20100156919
    Abstract: As set forth herein, a computer-implemented method is employed to place personalized text into an image. A location and region within the image is determined where the text is to be placed. The 3D geometry of the surface is estimated proximate to the location where the text is to be placed. A personalized text string is received. The personalized text string is incorporated into the image to appear as if it is rendered onto the surface or object according to the estimated 3D geometry.
    Type: Application
    Filed: December 19, 2008
    Publication date: June 24, 2010
    Applicant: XEROX CORPORATION
    Inventors: Raja Bala, Reiner Eschbach, Zhigang Fan, Jan P. Allebach, Charles A. Bouman, Hengzhou Ding, Geoffrey J. Woolfe
  • Publication number: 20100142003
    Abstract: A system is employed to reveal a watermark in a document. A watermark generator is utilized to select the placement and at least one colorant combination of an image and at least one colorant combination for a watermark on a document, where the at least one colorant combination of the image and the watermark form a metameric pair. A printing system receives data from the watermark generator and places the image and the watermark on the document. A decoder comprising a narrow band illumination element is selected or tuned to a wavelength corresponding to the colorant combinations utilized by the printing system to reveal the watermark placed thereon.
    Type: Application
    Filed: December 5, 2008
    Publication date: June 10, 2010
    Applicant: Xerox Corporation
    Inventors: Karen M. Braun, Raja Bala, Robert P. Loce
  • Patent number: 7733478
    Abstract: One aspect of the disclosure is directed to a calibration system. The calibration system includes an imaging device including a predetermined print engine capable of being calibrated and a calibration sheet. The calibration sheet includes at least one visible calibration reference region including a given mix of pre-selected reference colorants printed in the calibration reference region on the calibration sheet. The pre-selected reference colorants have been previously printed on the printable calibration sheet using a different imaging device that is different than the given imaging device and that has the same print engine as the given imaging device. The calibration sheet includes freshly printable target regions on the calibration sheet. The given imaging device is configured to enter into the calibration mode, wherein the given imaging device is configured to freshly print a mix of colorants corresponding to the pre-selected reference colorants onto at least one of the target regions.
    Type: Grant
    Filed: October 24, 2008
    Date of Patent: June 8, 2010
    Assignee: Xerox Corporation
    Inventors: Robert M. VanDuyn, Raja Bala
  • Patent number: 7724406
    Abstract: A method for compensating for color drift in a printer includes determining a first true tone response curve for a color channel when said printer is in a first state. A first estimated tone response curve for the color channel is also determined when said printer is in the first state. A second estimated tone response curve for the color channel is determined when the printer is in a second, color-drifted state relative to the first state. A second true tone response curve for the color channel is mathematically predicted using the first true tone response curve, the first estimated tone response curve, and the second estimated tone response curve. The first and second estimated tone response curves are estimated using a 2×2 printer model. A printing apparatus includes an image processing unit for implementing the color-drift correction process.
    Type: Grant
    Filed: January 31, 2006
    Date of Patent: May 25, 2010
    Assignee: Xerox Corporation
    Inventors: Shen-ge Wang, Raja Bala, Vishal Monga
  • Patent number: 7706034
    Abstract: What is provided is a system and method for node set construction and look-up table generation to transform image data in the form of color values of an input color image in an input color space to an output color space of an image output system. In the present method, node locations are selected based upon an importance value generated by a significance function which describes a relative importance of a given color value in the input image or a region thereof. A distance weighting function is also provided which is applied to the significance function to balance the significance of a given node against a relative positioning of all other nodes in the multi-dimensional grid. Nodes can be added or deleted according to methods also described herein. Accordingly, a multi-dimensional look-up table is generated wherein node tiling is based upon a significance of color values of an input image.
    Type: Grant
    Filed: September 11, 2007
    Date of Patent: April 27, 2010
    Assignee: Xerox Corporation
    Inventors: Vishal Monga, Raja Bala
  • Publication number: 20100086230
    Abstract: A method of retaining original natural language commands along with the mathematical LUT transform of the commands and a private tag within the same ICC profile. The private tag can be read only by an exclusive or proprietary application or color management module. When a user loads a color editing profile into the proprietary application, the natural language commands could then be read from the private tag and displayed on a user interface. The user can then immediately see the qualitative effect of the color editing profile and provide selected modifications to the commands and retain a new set of commands stored in another profile.
    Type: Application
    Filed: October 7, 2008
    Publication date: April 8, 2010
    Applicant: Xerox Corporation
    Inventors: Raja Bala, Geoffrey J. Woolfe
  • Patent number: 7688470
    Abstract: Disclosed are systems and methods for color calibration incorporating gray-component replacement, and more particularly, controlling gray component replacement in a color output device by applying a pre-defined transformation to a plurality of non-black channels to obtain at least one intermediate variable, and determining at least one output black (K) value from both the black channel input value and the intermediate variable, in order to provide control of gray component replacement in the color output device.
    Type: Grant
    Filed: December 20, 2006
    Date of Patent: March 30, 2010
    Assignee: Xerox Corporation
    Inventors: Vishal Monga, Raja Bala
  • Publication number: 20100054581
    Abstract: A method and system convert an original digital image being represented by a first color space to a digital image being represented by a second color space by transforming the original image data represented by a first color space to second image data being represented by a second color space, the transformation causing the colors of the transformed image data to be substantially encodable in the second color space. The second image data represented by the second color space is transformed to third image data represented by the first color space, the transformation causing the colors of the transformed image data to be substantially encodable in the first color space. Distortions in the third image data represented by the first color space are corrected to form corrected image data represented by the first color space, and the corrected image data represented by the first color space is transformed to fourth image data represented by the second color space.
    Type: Application
    Filed: August 29, 2008
    Publication date: March 4, 2010
    Applicant: Xerox Corporation
    Inventors: Raja Bala, Michael Branciforte, Reiner Eschbach
  • Publication number: 20100040282
    Abstract: A method and system for identifying a fluorescence mark in a printed document includes using an image acquisition device to derive an input digital image that represents a printed document including a background and a fluorescence mark adjacent the background. The input digital image includes multiple color channel digital images, with each color channel digital image comprising a plurality of pixels each defined by a gray value. For each pixel of at least one of the color channel digital images, the gray value is adjusted based upon a variance of adjacent pixel gray values to define a filtered digital image including a plurality of pixels each defined by an adjusted gray value. Some pixels of the filtered digital image correspond to low variance regions of the input digital image and other pixels of the filtered digital image correspond to high variance regions of the input digital image.
    Type: Application
    Filed: August 14, 2008
    Publication date: February 18, 2010
    Applicant: XEROX CORPORATION
    Inventors: Raja Bala, Reiner Eschbach, Yonghui Zhao
  • Patent number: 7652791
    Abstract: Consistency of document reprints is improved by recording characteristics of a reference printing system used to produce a reference printing of a document, determining related characteristics of a reprint printing system, retrieving the recorded characteristics and compensating for differences between the reference system and the reprint system in the reprint system prior to using the reprint system to produce reprints of the document. Analytical test prints (TPs) are produced with the respective printing systems in close temporal association to the production of the respective reference prints and reprints. TPs can be customized according to aspects of the document. TP customization allows the compensation to address aspects of the printing systems that have a bearing on perceived consistency in the reprints. TPs can be customized with regard to colors in test patches or both the colors and locations of test patches on a page. Compensation is based on measurements of the TPs.
    Type: Grant
    Filed: July 18, 2006
    Date of Patent: January 26, 2010
    Assignee: Xerox Corporation
    Inventors: Ann L. McCarthy, Edul N. Dalal, Wencheng Wu, Dale R. Mashtare, Raja Bala
  • Patent number: 7652808
    Abstract: A system and method for gamut mapping includes a luminance compression algorithm for gamut mapping that varies across different parts of the image. In shadow regions, a soft compression function is applied to bring out the detail. In other regions, including areas with high local contrast, a hard clipping function is applied to preserve local contrast. The algorithm adaptively blends between these two functions to ensure that the overall compression function is spatially smooth. The system and method may also use chrominance information to compute “perceived lightness”, to be used as input to the low-pass filter. Also, the blending function ?( ) could be a function of chrominance as well as luminance.
    Type: Grant
    Filed: December 11, 2003
    Date of Patent: January 26, 2010
    Assignee: Xerox Corporation
    Inventor: Raja Bala
  • Patent number: 7639260
    Abstract: Provided herein are teachings directed to overcoming the problem of erroneous color reproduction on a color output device such as a color display. The teachings herein provide a system and apparatus for correcting color image data input to a display device by displaying a target of color patches of known input values on the display device, and capturing an image of the target with a digital camera. This is followed by extracting camera signals from the image which correspond to the color patches, and deriving a tone response calibration for the projector from the camera signals and the input values.
    Type: Grant
    Filed: December 15, 2004
    Date of Patent: December 29, 2009
    Assignee: Xerox Corporation
    Inventors: Raja Bala, Karen M. Braun, Robert J. Rolleston
  • Patent number: 7639401
    Abstract: Provided herein are teachings directed to overcoming the problem of erroneous color reproduction on a color output device such as a color display. The teachings herein provide a method for correcting color image data input to a display device by displaying a target of color patches of known input values on the display device, and capturing an image of the target with a digital camera. This is followed by extracting camera signals from the image which corresponds to the color patches, and deriving a tone response calibration for the projector from the camera signals and the input values.
    Type: Grant
    Filed: December 15, 2004
    Date of Patent: December 29, 2009
    Assignee: Xerox Corporation
    Inventors: Raja Bala, Karen M. Braun, Robert J. Rolleston
  • Publication number: 20090296156
    Abstract: A device, system, and method for reducing the pitch-to-pitch variation of color using pitch-based linearization of halftone screens are presented. A selection of images is printed at different pitches, and each image is measured and tracked with its pitch. Pitch-based TRCs are constructed using patches, which may be scheduled during print run or during machine diagnostic process and halftone dots are constructed and uploaded in the image path for each pitch. The updated dots are then used to produce a linearized halftone image for transfer to a print surface which results in improved color balance.
    Type: Application
    Filed: May 27, 2009
    Publication date: December 3, 2009
    Applicant: Xerox Corporation
    Inventors: Lalit Keshav Mestha, Richard Leighton Howe, Raja Bala
  • Publication number: 20090279111
    Abstract: In accordance with the disclosure, a method is provided for processing color images for rendering on a color image. The method comprises receiving a plurality of device color separations for an image intended for rendering on a color image device; forming at least one intermediate image by interleaving pixels from at least two of the device color separations, compressing the at least one intermediate image in a compression module; decompressing the at least one intermediate image in a decompression module; processing the at least one decompressed intermediate image through a multidimensional calibration transform to output a calibrated device color separation; and, the device color separations include at least three colors.
    Type: Application
    Filed: May 9, 2008
    Publication date: November 12, 2009
    Applicant: Xerox Corporation
    Inventors: RAJA BALA, VISHAL MONGA
  • Publication number: 20090237682
    Abstract: The appearance of a color print viewed under UV illumination is predicted using a target comprising color patches each printed using a known coverage of printer colorant(s). In one case, the target is illuminated using a UV light source and an electronic image of the target is captured using a digital camera or the like. In another case, a spectrophotometer is used both with and without a UV cutoff filter to measure the target. The captured image data or the spectrophotometric measurements are used to derive a UV printer characterization model that relates any arbitrary combination of printer colorants to a predicted UV color appearance value. Metameric colorant mixture pairs for visible light and UV light viewing can be determined using the UV model together with a conventional visible light printer characterization model. A visual matching task is used to determine a correction factor for the UV printer characterization model.
    Type: Application
    Filed: March 21, 2008
    Publication date: September 24, 2009
    Applicant: Xerox Corporation
    Inventors: Raja Bala, Yonghui Zhao
  • Publication number: 20090195796
    Abstract: What is provided herein is a method for automatically selecting a subset of pages from a multi-page document for image processing wherein each selected page is substantially different from all other pages according to certain features of interest and wherein the combined content of the selected pages approximately represents the content in the entire document. Selected pages are clustered wherein each page is represented by a feature vector meaningfully related to the task to be performed. A matrix of feature vectors is analyzed. Basis vectors are extracted from the matrix using rank-reduction techniques. Clustering is performed by subspace projection of page features onto the basis vectors with each page being assigned to a cluster to which that page maximally projects. Representative pages are selected from each cluster. The representative pages can then be used as input to a secondary process.
    Type: Application
    Filed: February 1, 2008
    Publication date: August 6, 2009
    Applicant: XEROX CORPORATION
    Inventors: VISHAL MONGA, Raja Bala