Patents by Inventor Douglas G. Keithley
Douglas G. Keithley 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).
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Patent number: 9678334Abstract: An image forming apparatus performs periodic line based image transformation in order to correct for irregularities in a mirror and for mechanical disturbances that may occur during the rotation of the mirror. The irregularities of the mirror and the mechanical disturbances that occur during the rotation of the mirror may be measured at installation or may be measured during an operation of the image formation apparatus. The characteristics of the mirror are stored as configuration data, which is referenced by a direction of rotation. The image forming apparatus adjusts image data according to the configuration data. The adjustment may occur through data manipulation in stored image data. Alternatively, the adjustment may occur through the control of a pixel rate used to modulate the image data into a transmitted laser beam. The image data may be received by a host device or the image data may be generated by a scanner.Type: GrantFiled: June 13, 2012Date of Patent: June 13, 2017Assignee: Marvell International Ltd.Inventors: Douglas G. Keithley, Gregory L. Unruh
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Patent number: 9563935Abstract: Systems, methods, and other embodiments associated with image scaling are described. According to one embodiment, a method includes acquiring a set of amplitude values describing pixels in an image. A target pixel is identified from the set of pixels and a preceding pixel is identified to the target pixel. An amplitude range of amplitudes is defined between the amplitude of the preceding pixel and the target pixel. The method determines whether the interpolation between the preceding pixel and target pixel will result in an interpolated pixel having an interpolated amplitude outside of the amplitude range. An interpolation slope is determined that reduces overshoot or undershoot in interpolation pixels generated between the target pixel and the preceding pixel.Type: GrantFiled: February 3, 2015Date of Patent: February 7, 2017Assignee: Marvell World Trade Ltd.Inventor: Douglas G. Keithley
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Patent number: 9542716Abstract: A system and method for processing digital images that efficiently buffers pixel data relating to digital images is disclosed. Pixel values are read from an image storage memory and temporarily stored in a buffer memory according to a non-raster pattern. The processing of pixels also occurs according to a more efficient non-raster patter.Type: GrantFiled: January 31, 2014Date of Patent: January 10, 2017Assignee: Marvell International Ltd.Inventors: Douglas G. Keithley, Gordon R. Clark, John D. Marshall, William R. Schmidt
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Patent number: 9104941Abstract: Methods of filtering random noise and salt and pepper noise that minimize a loss of detail in an image are described. Sample values of an image that are within a tolerance within a sliding window are used to normalize a sample centered in the sliding window to filter random noise and minimize a loss of detail in an image. Sample values of an image in a sliding window are sorted into a sorted array, and mapped to values based on pre-defined regions of the sorted array to filter salt and pepper noise and minimize a loss of detail in an image.Type: GrantFiled: November 29, 2012Date of Patent: August 11, 2015Assignee: Marvell International Ltd.Inventor: Douglas G Keithley
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Patent number: 9099182Abstract: Semi-volatile NAND flash memory systems, apparatuses, and methods for use are described herein. According to various embodiments, a semi-volatile NAND flash memory may be partitioned into various retention regions. Other embodiments may be described and claimed.Type: GrantFiled: May 15, 2014Date of Patent: August 4, 2015Assignee: Marvell International Ltd.Inventors: Mark D. Montierth, Randall D. Briggs, Douglas G. Keithley
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Patent number: 9053052Abstract: In one example, a direct memory access controller includes a memory interface, a requestor interface, and an address generator. The memory interface is configured to cause a memory to provide at least a subset of data stored in the memory. The requestor interface is configured to receive a request for a consecutively addressed subset of the data stored in the memory to be provided in a non-consecutive order. The address generator is in communication with the requestor interface and the memory interface. The address generator is configured to, based on the request, sequentially generate non-consecutive addresses of the requested subset of the data to cause the memory to provide the requested subset of data in the requested non-consecutive order.Type: GrantFiled: December 20, 2011Date of Patent: June 9, 2015Assignee: Marvell International Ltd.Inventors: William R. Schmidt, Douglas G. Keithley, Gordon R. Clark
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Publication number: 20150147004Abstract: Systems, methods, and other embodiments associated with image scaling are described. According to one embodiment, a method includes acquiring a set of amplitude values describing pixels in an image. A target pixel is identified from the set of pixels and a preceding pixel is identified to the target pixel. An amplitude range of amplitudes is defined between the amplitude of the preceding pixel and the target pixel. The method determines whether the interpolation between the preceding pixel and target pixel will result in an interpolated pixel having an interpolated amplitude outside of the amplitude range. An interpolation slope is determined that reduces overshoot or undershoot in interpolation pixels generated between the target pixel and the preceding pixel.Type: ApplicationFiled: February 3, 2015Publication date: May 28, 2015Inventor: Douglas G. KEITHLEY
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Patent number: 9041988Abstract: A method and apparatus for exposure correction in scanners are disclosed. In the method, exposure is corrected for pixels received in an image sensor array. Exposure time is tracked for the incoming pixel data and a calibration factor is determined for correcting the gain, and the calibration factor is adjusted based on the tracked exposure time. In the apparatus, a scanner includes an illumination source and a sensor for receiving pixel data. Using values stored in a memory, circuitry is provided for determining a calibration factor, for tracking exposure time for the pixel data and for adjusting the pixel data based on the calibration factor and exposure time.Type: GrantFiled: November 1, 2013Date of Patent: May 26, 2015Assignee: Marvell International Ltd.Inventor: Douglas G. Keithley
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Patent number: 8995018Abstract: A color space converter converts data points from one color space to another color space using a lookup table. Color space converters may be used in any device that involves image processing, such as displays and printers. An interface receives an input value in a first color space. A controller access a lookup table stored in memory to determine an upper bound and a lower bound of a subset of the color space. An output value is interpolated between the upper bound and the lower bound using interpolation values. The interpolation values of the last subset in any dimension of the color space are modified by a scale factor to approximate ideal values.Type: GrantFiled: June 23, 2014Date of Patent: March 31, 2015Assignee: Marvell International Ltd.Inventor: Douglas G. Keithley
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Patent number: 8976431Abstract: The color of a pixel in a scanned image is represented by two color components and is adjustable by interpolating between color component values obtained from elements in a bidimensional color remap look-up table. The table is sparsely populated and may be readily implemented in most scanner circuits without adding memory.Type: GrantFiled: January 13, 2014Date of Patent: March 10, 2015Assignee: Marvell International Ltd.Inventor: Douglas G. Keithley
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Patent number: 8976417Abstract: An optical scanning device performs sequential scanning passes. Individual pixels are scanned in response to a clock whose frequency is dithered in repeatable cycles to reduce electro-magnetic interference, and scanning passes are coordinated with the repeatable cycles.Type: GrantFiled: October 14, 2011Date of Patent: March 10, 2015Assignee: Marvell World Trade Ltd.Inventor: Douglas G. Keithley
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Patent number: 8958636Abstract: Embodiments of the present disclosure provide a method of color trapping to improve perceived image quality. The color trapping may be subject to one or more configurable parameters, to accommodate differences in printing processes and conditions.Type: GrantFiled: July 26, 2011Date of Patent: February 17, 2015Assignee: Marvell International Ltd.Inventors: Jay McDougal, Douglas G. Keithley
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Patent number: 8953907Abstract: Systems, methods, and other embodiments associated with image scaling are described. According to one embodiment, a method acquiring a set of amplitude values describing pixels in an image. Image scaling is performed on the image. A target pixel is identified from the set of pixels. A preceding pixel is identified to the target pixel. An amplitude range of amplitudes is defined between the amplitude of the preceding pixel and the target pixel. It is determined whether the interpolation between the preceding pixel and target pixel will result in an interpolated pixel having an interpolated amplitude outside of the amplitude range. Based on this determination, an interpolation slope is selected that reduces overshoot or undershoot in interpolation pixels generated between the target pixel and the preceding pixel.Type: GrantFiled: May 17, 2012Date of Patent: February 10, 2015Assignee: Marvell World Trade Ltd.Inventor: Douglas G. Keithley
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Patent number: 8947734Abstract: A pulse width modulation technique is disclosed for use in an image forming device such as a laser printer or a photocopier. The technique implements a pacer to synthesize the frequency of a serializer circuit by stretching (or shrinking) pixel pulse train data. The pacer stretches the pixel pulse train data in accord with increment data that is based upon information about the image forming device, such as the number of bits in the pixel pulse train data, the number of bits in print engine pulse train, the target print engine frequency, and the serializer frequency. The technique can be implemented with digital circuits that provide digital test data.Type: GrantFiled: July 25, 2007Date of Patent: February 3, 2015Assignee: Marvell International Ltd.Inventors: John D. Marshall, Douglas G. Keithley, Richard D. Taylor
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Patent number: 8941884Abstract: Various techniques for generating transformed tables by applying transformations indicated in a transformation table to a first threshold halftone table that is unsuitable for tiling an image as part of an image half-toning process are described. A block of the transformed tables represent a second threshold halftone table that is suitable for the half-toning process, wherein the second threshold halftone table is larger than the first threshold halftone table, such that the block is too large to be stored in the memory. A half-toned image of the image is generated based at least in part on the second threshold halftone table.Type: GrantFiled: November 29, 2012Date of Patent: January 27, 2015Assignee: Marvell International Ltd.Inventor: Douglas G Keithley
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Patent number: 8928902Abstract: A method and apparatus for faster monochrome printing in an in-line electrophotographic printer is described. The printer is configured such that it has more light emitting sources for use in an image transfer assembly for black than for image transfer assemblies for any other color in the printer. When printing a color print job, less than all of the light emitting sources in the black image transfer assembly are used. A print controller directs print data for a monochrome print job to all of the available light emitting sources in the black image transfer assembly and increases the print medium transport speed. The system and method may be configured to operate with dedicated data channels for each light emitting source or may share some data channels for monochrome and color print jobs.Type: GrantFiled: June 10, 2013Date of Patent: January 6, 2015Assignee: Marvell International Ltd.Inventor: Douglas G. Keithley
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Patent number: 8903300Abstract: Embodiments of the present invention provide a multi-function device including a housing, a printing assembly disposed within the housing, the printing assembly being configured to print a document, and a copying assembly comprising a complementary metal-oxide-semiconductor (CMOS) image sensor and an illumination source disposed within the housing, the copying assembly further including a substantially flat transparent surface disposed in an optical path of the CMOS image sensor, the substantially flat transparent surface to support an object for image capture by the CMOS image sensor, wherein the illumination source is configured to provide illumination during image capture. Other embodiments may be described and/or claimed.Type: GrantFiled: August 18, 2009Date of Patent: December 2, 2014Assignee: Marvell World Trade Ltd.Inventors: Mark D. Montierth, Douglas G. Keithley, Richard D. Taylor
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Patent number: 8885006Abstract: A laser scanning assembly generates a laser beam and scans the laser beam through a plurality of scan lines to form desired dots. Each scan line is positioned to overlap an adjacent scan line and each dot includes a plurality of segments. The scanning assembly scans the laser beam through multiple scan lines to fully discharge each segment of each dot. The laser scanner assembly would typically be part of a laser printer.Type: GrantFiled: November 1, 2013Date of Patent: November 11, 2014Assignee: Marvell World Trade Ltd.Inventor: Douglas G. Keithley
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Patent number: 8836960Abstract: Imaging devices incorporating semi-volatile memory are described herein. According to various embodiments, device driver information may be stored in the semi-volatile NAND flash memory. Other embodiments may be described and claimed.Type: GrantFiled: December 27, 2007Date of Patent: September 16, 2014Assignee: Marvell International Ltd.Inventors: Mark D. Montierth, Randall D. Briggs, Douglas G. Keithley, Gary D. Zimmerman
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Patent number: 8837014Abstract: This disclosure describes techniques and apparatuses for reducing color fringes. In some embodiments, inaccuracies from color-insensitive sensors are corrected. Inaccuracies can be corrected in part by shortening a first illumination made temporally proximate a second illumination. By so doing, a center of the image captured for a first illumination is moved toward the image captured for a second illumination, which reduces a color fringe.Type: GrantFiled: November 7, 2013Date of Patent: September 16, 2014Assignee: Marvell International Ltd.Inventor: Douglas G. Keithley