Abstract: Methods and apparatuses for noise reduction include embodiments that use a weighted combination based on the presence of edges of two calculated demosaiced signals to produce a noise reduced signal. The noise reduced signal may be sharpened based on a calculated luminance of the two demosaiced signals.

Abstract: Methods, systems and apparatuses for determining and compensating for green imbalance in imagers. An estimated local green balance correction term is limited, e.g., between an upper and lower limit. The upper and lower limits are determined from a set of parameters. The parameters are determined during a calibration procedure. The parameters may be stored for a subset of possible pixel locations and parameters for each pixel not at a location corresponding to stored data may be determined by interpolation.

Abstract: A method, apparatus, and system for dynamic range estimation of imaged scenes for automatic exposure control. For a given exposure time setting, certain areas of a scene may be brighter than what a camera can capture. In cameras, including those experiencing substantial lens vignetting, a gain stage may be used to extend dynamic range and extract auto-exposure data from the extended dynamic range. Alternatively, dynamic range can be extended using pre-capture image information taken under reduced exposure conditions.

Abstract: Methods and apparatuses for image exposure include capturing a first image under a first illumination condition, determining a luminance of the first image at a plurality of sectors, capturing a second image under a second illumination condition employing an artificial light source, determining a luminance of the second image at the plurality of sectors, and determining if the artificial light source should be used to capture a final image using the luminances of the first and second images at the plurality of sectors. If the artificial light source is to be used, an output level of the light source is determined.

Abstract: Method, apparatus and system for determining a value for green-green imbalance and applying the value to green pixels to correct the imbalance are described. Average pixel values of green pixels within a kernel are calculated and an imbalance value is determined based on the averages. The imbalance value is added to or subtracted from all green pixel response values in the kernel to correct the imbalance.

Abstract: An image window is subdivided into a plurality of sub-windows arranged in a rectangular grid pattern. The average brightness of the window and each sub-window is determined. A sub-window is tagged as dark if its average brightness is a predetermined percentage of the window average brightness. If the sub-window in the center of the grid pattern is considered to be dark, a segmentation is performed to detect a main backlit subject. The comparison of sub-window brightness is continued from the center sub-window in outward sequential, side adjacent rows and columns of sub-windows. Each sub-window that meets the above-described criterion for being dark is tagged as dark. The image is considered to have a main backlit subject if, in one embodiment, the subject is comprised of a predetermined quantity of continuous, dark sub-windows.

Abstract: A solid state imaging device includes an array of active pixels and an infrared cut filter formed over the sensor. Optionally, a slot in the infrared cut filter allows infrared illumination to reach the sensor to be detected by pixels covered by a visually opaque filter and surrounded by pixels of special types that limit charge leakage and enable high dynamic range sensing of infrared illumination. A ratio of average infrared signal to average brightness indicates an amount of infrared illumination reaching the imaging device.

Abstract: Surface generation and positional gain adjustment techniques for an imager are described. Embodiments of the techniques use zones having flexible boundaries which can be reconfigured depending upon the type of lens being used in a given application. Each pixel within each zone is multiplied by a correction factor dependent upon the particular zone while the pixel is being read out from the array. The correction factors comprise coefficients that are different for each color channel and in some instances different for each corner of each color channel.

Abstract: A system and method for flare cancellation and image contrast restoration includes generating a histogram of pixel response values of pixels of an image and generating an adjustment signal having a luminance adjustment value responsive to the histogram. The system and method also includes adjusting the pixel response values of pixels of the image responsive to the adjustment signal to produce an adjusted image.

Abstract: An apparatus and method for measuring the breakpoint of a response curve representing the voltage output of an image array having an extended dynamic range. By flooding a light-opaque pixel with a charge and then applying an intermediate reset voltage to the pixel, the signal is read from the pixel and stored. The full reset voltage is applied to the pixel, and then the signal in the pixel is read and stored. The voltage output difference is the difference between the first and second stored signal. The voltage output difference is then used to determine the voltage of the knee point. Further, a conventional saturated pixel can be reset with an intermediate reset just prior to readout. The resulting signal can then be used to determine the voltage of the knee point.

Abstract: Surface generation and positional gain adjustment techniques for an imager are described. Embodiments of the techniques use zones having flexible boundaries which can be reconfigured depending upon the type of lens being used in a given application. Each pixel within each zone is multiplied by a correction factor dependent upon the particular zone while the pixel is being read out from the array. The correction factors comprise coefficients that are different for each color channel and in some instances different for each corner of each color channel.

Abstract: A solid state imaging device includes an array of active pixels and an infrared cut filter formed over the sensor. Optionally, a slot in the infrared cut filter allows infrared illumination to reach the sensor to be detected by pixels covered by a visually opaque filter and surrounded by pixels of special types that limit charge leakage and enable high dynamic range sensing of infrared illumination. A ratio of average infrared signal to average brightness indicates an amount of infrared illumination reaching the imaging device.

Abstract: Methods, systems and apparatuses for white balance calibration. A calibration correction matrix is specifically calibrated for each individual imager, thereby providing improved automatic white balance performance. The individual imager calibration corrects for variation of the spectral response among different imagers. The calibration correction matrix is placed before the gray checker module, which analyzes the chromaticity of the image pixels and supplies resulting statistics to the automatic white balance decision engine for use in automatic white balance operations. The calibration correction matrix may be implemented as a 3×3 matrix.

Abstract: An improved non-uniform sensitivity correction algorithm for use in an imager device (e.g., a CMOS APS). The algorithm provides zones having flexible boundaries which can be reconfigured depending upon the type of lens being used in a given application. Each pixel within each zone is multiplied by a correction factor dependent upon the particular zone while the pixel is being read out from the array. The amount of sensitivity adjustment required for a given pixel depends on the type of lens being used, and the same correction unit can be used with multiple lenses where the zone boundaries and the correction factors are adjusted for each lens. In addition, the algorithm makes adjustments to the zone boundaries based upon a misalignment between the centers of the lens being used and the APS array.

Abstract: A method and apparatus for applying exposure compensation to an image. Exposure correction limits inclusion of, but does not ignore, image highlights and lowlights.

Abstract: An improved non-uniform sensitivity correction algorithm for use in an imager device (e.g., a CMOS APS). The algorithm provides zones having flexible boundaries which can be reconfigured depending upon the type of lens being used in a given application. Each pixel within each zone is multiplied by a correction factor dependent upon the particular zone while the pixel is being read out from the array. The amount of sensitivity adjustment required for a given pixel depends on the type of lens being used, and the same correction unit can be used with multiple lenses where the zone boundaries and the correction factors are adjusted for each lens. In addition, the algorithm makes adjustments to the zone boundaries based upon a misalignment between the centers of the lens being used and the APS array.

Abstract: A method and apparatus for applying color correction to image signals provides different color corrections depending on a characterization associated with a pixel signal being processed or the gain applied to the pixel signal such as a value of a pixel signal being processed. The color corrections may be configured such that darker pixels have less color correction applied to them.

Abstract: Methods and apparatuses for sharpening imaging pixel signals. Embodiments provide methods of sharpening that preserves the pixel's saturation and apparatuses therefor. In essence, rather than changing only the pixels' luminance, the effective exposure of the pixel is changed.

Abstract: A method, apparatus, and system are provided by which image line data of an image frame is compressed before being stored to image line memory used in multiple image line processing.

Abstract: Methods and apparatuses for noise reduction of imager pixels signals. A weighted combination based on the presence of edges of two calculated demosaiced signals is used to produce a noise reduced signal. The noise reduced signal may be sharpened based on a calculated luminance of the two demosaiced signals.