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: 8760725Abstract: A method and system for generating a halftone image from an input image is disclosed. The method and system use error distribution and threshold perturbation that is based on the incoming tone value. A threshold bias table may be generated in real time for each incoming tone value. The values of the threshold bias tables are selected so that certain positions are forced to include a dot, in the case of light tone values, or not include a dot, in the case of dark tone values. A halftone process that uses threshold bias tables based on the incoming tone can reduce unnatural patterns in the image apparent to the casual observer, which results in a more pleasing image.Type: GrantFiled: November 12, 2009Date of Patent: June 24, 2014Assignee: Marvell International Ltd.Inventor: Douglas G. Keithley
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Patent number: 8762596Abstract: A direct memory access controller is set forth. The direct memory access controller includes first and second registers storing various values that are used to set the parameters of DMA transfers that take place during a single data transaction. The first register stores a start address location value used to define a start address at which direct memory access transfers for the transaction are to begin. The second register stores a value used to end data transfers of the data transaction. The DMA controller also includes transfer control circuitry for executing the data transaction. The transfer control circuitry is adapted to automatically execute multiple, consecutive data transactions using the values stored in the first and second registers.Type: GrantFiled: February 8, 2011Date of Patent: June 24, 2014Assignee: Marvell International Ltd.Inventors: John D. Marshall, Douglas G. Keithley, William R. Schmidt
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Patent number: 8760714Abstract: 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: August 25, 2010Date of Patent: June 24, 2014Assignee: Marvell International Ltd.Inventor: Douglas G. Keithley
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Patent number: 8690061Abstract: An image forming apparatus includes a scanning region and a user interface region adjacent to the scanning region. In the user interface, a first illuminated indicator corresponds to a function of the image forming apparatus. A light source is operable to illuminate an object in the scanning region. A first light conveying member is coupled to the illuminated indicator and operable to receive light from the light source.Type: GrantFiled: September 13, 2012Date of Patent: April 8, 2014Assignee: Marvell International Ltd.Inventors: James A. Hall, Jr., Douglas G. Keithley
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Patent number: 8681381Abstract: A method and system for generating a halftone image from an input image is disclosed. Visible artifacts caused by the correlation of one or more colors or color planes are avoided because the halftone image analysis for one color affects the halftone image analysis for subsequent colors. A printer controller analyzes at least a part of the input image to dynamically set a sequence of the plurality of colors. Halftone image analysis is carried out in the sequence of the plurality of colors to generate the halftone image.Type: GrantFiled: November 12, 2009Date of Patent: March 25, 2014Assignee: Marvell International Ltd.Inventors: Douglas G. Keithley, Randall D. Briggs
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Publication number: 20140055550Abstract: 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: ApplicationFiled: November 1, 2013Publication date: February 27, 2014Applicant: Marvell International Technology Ltd.Inventor: Douglas G. Keithley
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Patent number: 8643661Abstract: 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 pattern.Type: GrantFiled: May 11, 2007Date of Patent: February 4, 2014Assignee: Marvell International Ltd.Inventors: Douglas G. Keithley, Gordon R. Clark, John D. Marshall, William R. Schmidt
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Patent number: 8630031Abstract: 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: June 13, 2007Date of Patent: January 14, 2014Assignee: Marvell International Ltd.Inventor: Douglas G. Keithley
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Patent number: 8625145Abstract: Embodiments of the present disclosure provide a method for estimating usage of a print substance. The method comprises receiving a plurality of pixels of a page to be printed, and generating, for one of the plurality of pixels, a look-up address based on (i) pixel bits of the one of the plurality of pixels, and (ii) pixel bits of one or more other pixels proximal to the one of the plurality of pixels. The method further comprises estimating an amount of print substance deposited on the page at a location associated with the one of the plurality of pixels based on reference to a print substance amount in a table of print substance amounts, wherein the reference to the print substance amount in the table is made using the look-up address.Type: GrantFiled: June 21, 2011Date of Patent: January 7, 2014Assignee: Marvell International Ltd.Inventors: Roy G. Moss, Douglas G. Keithley, Nilotpal Sensarkar
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Patent number: 8599455Abstract: A method and apparatus for performing color plane adjustment are provided. In one embodiment, an apparatus comprises a set of inputs for receiving a first input value and a second input value in a color space. The apparatus also comprises a color plane adjustment component operative to adjust the first input value and the second input value by amounts that depend on a distance of the first input value and second input value, respectively, from a value of neutral gray in the color space. The apparatus further comprises a set of outputs for outputting the adjusted first and second values. A related method and computer program are disclosed. Other embodiments are disclosed, and each of the embodiments can be used alone or together in combination.Type: GrantFiled: June 10, 2011Date of Patent: December 3, 2013Assignee: Marvell International Ltd.Inventors: Randall D. Briggs, Douglas G. Keithley
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Patent number: 8599453Abstract: 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: December 18, 2012Date of Patent: December 3, 2013Assignee: Marvell International Ltd.Inventor: Douglas G Keithley
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Patent number: 8587625Abstract: 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: December 23, 2011Date of Patent: November 19, 2013Assignee: Marvell International Technology Ltd.Inventor: Douglas G. Keithley
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Patent number: 8587827Abstract: Embodiments of the present invention provide an integrated circuit having analog front end (AFE) circuitry to convert an analog signal to a digital signal, the analog signal being associated with an image captured by a sensor of an imaging device, illumination drive circuitry to drive an illumination source of the imaging device, and one or more transformation elements to operate on the digital signal to provide image correction of the captured image, wherein the AFE circuitry, the illumination drive circuitry, and the one or more transformation elements are integrated on a single chip. Other embodiments may be described and/or claimed.Type: GrantFiled: August 10, 2009Date of Patent: November 19, 2013Assignee: Marvell International Ltd.Inventors: Mark D. Montierth, Douglas G. Keithley, Richard D. Taylor
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Patent number: 8582187Abstract: 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: July 12, 2011Date of Patent: November 12, 2013Assignee: Marvell International Ltd.Inventor: Douglas G. Keithley
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Patent number: 8559048Abstract: Imaging devices incorporating semi-volatile NAND flash memory are described herein. According to various embodiments, demonstration page information may be stored in the semi-volatile NAND flash memory, which may be reused and incorporated back into the memory pool after the demonstration page information is no longer needed. Other embodiments may be described and claimed.Type: GrantFiled: January 14, 2013Date of Patent: October 15, 2013Assignee: Marvell International Ltd.Inventors: Mark D. Montierth, Randall D. Briggs, Douglas G. Keithley, David A. Bartle
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Patent number: 8553304Abstract: A piezoelectric actuator corrects for imperfections in printed material caused by the vertical rotation of a photosensitive image forming surface, such as a photoconductive drum. The piezoelectric actuator may be mounted to the base of a reflective surface holder, such as a mirror holder, that holds a mirror. The reflective surface holder may be operable to horizontally rotate the mirror as the mirror reflects a laser onto the photosensitive image forming surface. A power supply in communication with the piezoelectric actuator applies a voltage to the piezoelectric actuator. The resulting voltage allows the piezoelectric actuator to tilt the mirror in a vertical direction. A memory storage device may store tilt adjustment data usable by a microprocessor or controller to control the amount of voltage the power supply supplies to the piezoelectric actuator.Type: GrantFiled: September 13, 2012Date of Patent: October 8, 2013Assignee: Marvell International Ltd.Inventor: Douglas G. Keithley
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Patent number: 8549342Abstract: A device for adjusting the timing of at least one edge of an output pulse created in response to a reference pulse is disclosed. Such a device may include a first memory circuit having two or more first memory cells and a second memory circuit also having two or more second memory cells. The first memory circuit may be configured to periodically sample the reference pulse at the rising edges of a first sample clock while the second memory circuit may be configured to periodically sample the reference pulse at the falling edges of the first sample clock. A combinatorial logic circuit may also be included to produce the output pulse having at least one adjusted edge based on a set of timing instructions and timing information provided by the first and/or second memory circuits.Type: GrantFiled: April 5, 2011Date of Patent: October 1, 2013Assignee: Marvell International Ltd.Inventors: Roy G. Moss, Douglas G. Keithley, Richard N. Woolley
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Patent number: 8537424Abstract: Some of the embodiments of the present disclosure provide a method comprising forming an array comprising a plurality of microcells, each microcell of the plurality of microcells including a plurality of pixels; for each pixel in each of the plurality of microcells, assigning (i) a respective pixel offset factor that is associated with a relative position of the pixel in the respective microcell, and (ii) a respective microcell offset factor that is associated with an index of the respective microcell; and for each pixel in each of the plurality of microcells, determining a respective final offset factor that is based at least in part on the respective pixel offset factor and the respective microcell offset factor. Other embodiments are also described and claimed.Type: GrantFiled: August 17, 2010Date of Patent: September 17, 2013Assignee: Marvell International Ltd.Inventors: Douglas G. Keithley, Roy G. Moss
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Patent number: 8496176Abstract: A scanning apparatus and method for entering a user input into the apparatus uses a non-electrical control device having a target undersurface, which can be manually manipulated to a particular setting. The particular setting of the non-electrical control device is determined by processing an image of at least a portion of the target undersurface captured by a scan sensor of the scanning apparatus.Type: GrantFiled: August 30, 2010Date of Patent: July 30, 2013Assignee: Marvell International Technology Ltd.Inventors: James A. Hall, Jr., Douglas G. Keithley
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Patent number: 8462363Abstract: 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: September 13, 2012Date of Patent: June 11, 2013Assignee: Marvell International Ltd.Inventor: Douglas G. Keithley