Abstract: A system and method of reducing noise in output image data is provided. Grayscale image data having a plurality of pixels is received and processed. During processing, pixels which may produce noise are identified, and a mask associated with the image data is generated. The mask provides information related to the pixels, such as opaque and transparent regions for overlaying the pixels. The image data and the mask are compressed and stored. The mask assists in preventing the identified pixels from being visible when the image data is output, thereby reducing the noise in the image.

Abstract: Methods, devices and computer readable media for implementing a “selective gray world” approach for color balancing are described. The disclosed techniques involve the use of noise-optimized selection criteria and, more specifically, in some embodiments, the interpolation between corresponding values in noise-optimized weighting tables when calculating white balance gains. Estimated scene lux levels may provide a valuable indicator of expected scene noise levels. The image processing techniques described herein may be executed by an image capture device or a general purpose processor (e.g., personal computer) executing a user-level software application. The described color balancing techniques may be implemented by dedicated or general purpose hardware, general application software, or a combination of software and hardware in a computer system.

Abstract: A novel chromaticity space is disclosed that may be used as a framework to implement an auto-white balance solution or other color image processing solutions that take advantage of the particular properties of the novel chromaticity space. The chromaticity space may be defined by using a series of mathematical transformations having parameters that are optimized to adapt to specific sensors' spectral sensitivities. The unique properties of the novel chromaticity space provide a conscious white point constraining strategy with clear physical meaning. In this chromaticity space, the ranges of possible white points under different kinds of lighting conditions can be defined by polygons. Because of the physical meaning the chromaticity space, the projection that is needed to bring an initially “out-of-bounds” white point back into the polygon also carries physical meaning, making the definition of projection behavior and its consequences conceptually clean and predictable.

Abstract: Methods, devices and computer readable media for implementing novel dominant color alleviation techniques for color balancing are described. The techniques take advantage of unique properties of 2D image data histograms accumulated in a chromaticity space, along with other factors such as estimated scene lux and knowledge of plausible scene illuminant white point values within the chromaticity space. The accumulated 2D image data histograms may be refined and “trimmed,” such that the resultant image data passed to an auto white balance solution has much less influence from the dominant colors in the image, even those that overlap the plausible scene illuminant color region. The described techniques provide for white point estimates that are much less prone to dominant color failures.

Abstract: This disclosure pertains to devices, methods, and computer readable media for improved accuracy of color correction matrix (CCM) coefficient determination based on estimated white point, while maintaining a relatively smooth variation of CCM coefficients over the white point space. The techniques disclosed herein may be achieved via the storage of a limited number of determined CCM multiplier vectors and thus be effective in the camera image pipelines of real image capture devices. With the more accurate CCMs calculated with the disclosed techniques, visible improvement in rendered colors may be achieved as compared to using interpolation from a handful of corner CCMs. The color correction techniques described herein may be implemented by dedicated or general purpose hardware, general application software, or a combination of software and hardware in a computer system.

Abstract: An imaging system may include a dual-band image sensor that captures visible and near-infrared light and image processing circuitry that performs color corrections on images captured by the dual-band image sensor. The image processing circuitry may analyze each captured image in two different color spaces to determine what type of light source lit each image. The image processing circuitry may determine whether an image was lit by a light source having a relatively high proportion of near-infrared emissions such as an incandescent light, a light source having a relatively low proportion of near-infrared emissions such as a fluorescent light, or a light source having an intermediate proportion of near-infrared emissions such as sunlight or other blackbody radiator. After determining what type of light source lit an image, the image processing circuitry may adjust color balances in that image using a color correction matrix associated with that type of light source.

Abstract: Disclosed is a system and method for monochrome or binary compression, and more particularly compression of binary images segmented in a binary domain into at least two regions of different image types, where the regions are compressed using different compression techniques.

Abstract: A method and system modify a rasterized digital image to reduce registration artifacts, the image having a black plane and a color plane by determining if a pixel is part of a connected black region and if the pixel is part of a connected color region. It is determined if the pixel is part of a connected black region and a connected color region that are contiguous. A dilation operation is performed on the color plane value of the pixel if the pixel is part of a connected black region and a connected color region that are contiguous.

Abstract: A method and system modify a rasterized digital image to reduce registration artifacts, the image having a black plane and a color plane by determining if a pixel is part of a connected black region and if the pixel is part of a connected color region. It is determined if the pixel is part of a connected black region and a connected color region that are contiguous. A dilation operation is performed on the color plane value of the pixel if the pixel is part of a connected black region and a connected color region that are contiguous.

Abstract: A color reproduction system with drift correction that includes a storage module, an image processing module, a printer, a scanner, and a calibration module. The storage module stores one or more current linear response halftones and a set of device independent color signals representative of a calibration target. The image processing module receives the stored device independent color signals and generates binary print data based on the one or more current linear response halftones. The printer prints a copy of the calibration target in accordance with the binary print data. The scanner scans the copy of the calibration target printed by the printer to generate scanned image data that corresponds to the copy of the calibration target.

Abstract: An image processing method in which OCR is used to guide the text tokenization. More particularly, OCR is first performed on each symbol in the scanned image. For example, a symbol may be a number, letter, or other character. During the tokenization process, the OCR results are used to select appropriate matching criteria for each symbol. The symbols that are recognized as different characters are not allowed to be clustered into the same group. The symbols with the same OCR results are clustered according to the recognition confidence levels.

Abstract: An imaging system may include a dual-band image sensor that captures visible and near-infrared light and image processing circuitry that performs color corrections on images captured by the dual-band image sensor. The image processing circuitry may analyze each captured image in two different color spaces to determine what type of light source lit each image. The image processing circuitry may determine whether an image was lit by a light source having a relatively high proportion of near-infrared emissions such as an incandescent light, a light source having a relatively low proportion of near-infrared emissions such as a fluorescent light, or a light source having an intermediate proportion of near-infrared emissions such as sunlight or other blackbody radiator. After determining what type of light source lit an image, the image processing circuitry may adjust color balances in that image using a color correction matrix associated with that type of light source.

Abstract: Systems and methods are provided for calibrating image sensors. In some embodiments, a processing module of an image system can automatically perform a self-calibration process after a production unit of an image sensor has been integrated into an end product system. For example, the processing module can calibrate a production unit based on one or more reference pixels of the production unit, where the one or more reference pixels have minimal color filtration. In some embodiments, the processing module may perform local calibrations by correcting specifically for spatial variations in a color filter array (“CFA”). In some embodiments, the processing module can perform global calibrations by correcting for optical density variations in the CFA. In some embodiments, a processing module can determine whether the cause of production variations is related to production variations of a CFA or production variations of an infrared (“IR”) cutoff filter.

Abstract: An image system with a dual layer photodiode structure is provided for processing color images. In particular, the image system can include an image sensor that can include photodiodes with a dual layer photodiode structure. In some embodiments, the dual layer photodiode can include a first layer of photodiodes (e.g., a bottom layer), an insulation layer disposed on the first layer of photodiodes, and a second layer of photodiodes (e.g., a top layer) disposed on the insulation layer. The first layer of photodiodes can include one or more suitable pixels (e.g., green, blue, clear, luminance, and/or infrared pixels). Likewise, the second layer of photodiodes can include one or more suitable pixels (e.g., green, red, clear, luminance, and/or infrared pixels). An image sensor incorporating dual layer photodiodes can gain light sensitivity with additional clear pixels and maintain luminance information with green pixels.

Abstract: Systems and methods are provided for obtaining adaptive exposure control and dynamic range extension of image sensors. In some embodiments, an image sensor of an image system can include a pixel array with one or more clear pixels. The image system can separately control the amount of time that pixels in different lines of the pixel array are exposed to light. As a result, the image system can adjust the exposure times to prevent over-saturation of the clear pixels, while also allowing color pixels of the pixel array to be exposed to light for a longer period of time. In some embodiments, the dynamic range of the image system can be extended through a reconstruction and interpolation process. For example, a signal reconstruction module can extend the dynamic range of one or more green pixels by combining signals associated with green pixels in different lines of the pixel array.

Abstract: A system and method for rendering an image file for outputting a copy of an image represented by the image file. In some embodiments, rendering the image includes generating an output file, such as an output bitmap based on a predetermined halftone. In one embodiment, the system comprises an input module, and a processor. The input module obtains a page description of the image to be output. In some instances, the page description includes one or more level masks designed to impart corresponding transparency levels to one or more objects in the page description.

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.

Abstract: A method and system modify a rasterized digital image to reduce registration artifacts, the image having a black plane and a color plane by determining if a pixel is part of a connected black region and if the pixel is part of a connected color region. It is determined if the pixel is part of a connected black region and a connected color region that are contiguous. A dilation operation is performed on the color plane value of the pixel if the pixel is part of a connected black region and a connected color region that are contiguous.

Abstract: A method and system modify a rasterized digital image to reduce registration artifacts, the image having a black plane and a color plane by determining if a pixel is part of a connected black region and if the pixel is part of a connected color region. It is determined if the pixel is part of a connected black region and a connected color region that are contiguous. A dilation operation is performed on the color plane value of the pixel if the pixel is part of a connected black region and a connected color region that are contiguous.

Abstract: An image processing method in which OCR is used to guide the text tokenization. More particularly, OCR is first performed on each symbol in the scanned image. For example, a symbol may be a number, letter, or other character. During the tokenization process, the OCR results are used to select appropriate matching criteria for each symbol. The symbols that are recognized as different characters are not allowed to be clustered into the same group. The symbols with the same OCR results are clustered according to the recognition confidence levels.