Abstract: Techniques for modifying data of an image that can be implemented in a digital camera, video image capturing device and other optical systems are provided to correct for non-uniform illumination and/or effects of saturation appearing in data obtained using one or more artificial illumination sources. In an implementation, correction factors are derived using data from at least two images that have been captured with different illumination levels of the object scene and close in time to the capture of the image of interest. Typically, the image of interest is of higher resolution than at least one of the at least two images.

Abstract: A system and method for determining an FFT window location for reception of an OFDM signal received over a transmission channel. The OFDM signal includes a plurality of symbols each having a guard interval. The system includes a correlation module that determines a location of maximum correlation in a first symbol, an FFT module to perform an FFT on the OFDM signal based upon an initial FFT window location, and an adjustment module. The adjustment module determines a plurality of permissible echo location options based upon the initial FFT window location, selects a permissible echo location option that corresponds most closely to the location of maximum correlation, and adjusts the initial FFT window location based upon the selected permissible echo location option so that the adjusted FFT window location includes substantially all of a useful symbol length of the first symbol while a maximum number of echoes are included within the guard interval of the first symbol.

Abstract: A method for operating a time-interleaved analog-to-digital converter for converting an analog input to a digital output using a time-interleaved analog-to-digital converter, wherein the time-interleaved analog-to-digital converter comprises an array of M sub ADCs (ADC1, ADC2, . . . , ADCM), where M is an even integer, and each row of the array comprises one of the M sub ADCs. The method comprises the step of, for every sampling instant n, where n is an integer in a sequence of integers, converting the analog input by means of the sub ADC in row k(n) of the array, wherein 1?k(n)?M. A value between 1 and M is assigned to k(n) for the first sample instant, and k(n+1) is selected such that a) k(n+1)>M/2 if k(n)?M/2, otherwise k(n+1)?M/2; b) M/2?1?|k(n+1)?k(n)|?M/2+1; and c) k(n+1)=k(m+1) if and only if n?m is an integer multiple of M. A time interleaved analog-to-digital converter operating in accordance with the method is also disclosed.

Abstract: A digital camera acquires a first image in a sequence of images by loading it into a unified memory space of the digital camera in a first order and processing it in a second order. Before the first image is completely processed, the digital camera starts acquiring a second image and overwriting at least a processed portion of the first image in the unified memory space with image data of the second image.

Abstract: An image capture system is presented where the dynamic range of photo imaging devices, such as a still or video camera, is increased by varying sensor exposure time on a pixel-by-pixel basis under digital camera processor control. The systems photo sensors are continuously illuminated without reset over the exposure interval. In addition to being interrogated at the end of the exposure interval, the pixels are also non-destructively interrogated at one or more intermediate times during the interval. At each interrogation, the image capture system determines individually whether the pixels have saturated and if not, the parameter value is recorded; if the pixel has saturated, the previously stored value from the preceding interval is maintained. To produce the final sensor value for the whole exposure interval, the data for pixels that reached the saturation level are adjusted to compensate for their shortened exposure.

Abstract: A method and apparatus for blending a video signal responsive to a chroma motion result is disclosed. The method and apparatus are configured to determine whether any chroma motion exists within the video signal and providing the chroma motion result, to provide a first blending signal based on the chroma motion result; to provide a second blending signal based on the chroma motion result; to modulate temporal filtered luma and chroma components of the video signal with the first blending signal, to modulate spatial filtered luma and chroma components of the video signal with the second blending signal, and to add the modulated temporal luma and chroma signals to the modulated spatial luma and chroma signals to provide a blended video signal.

Abstract: Video data of successive image frames are processed in a digital camera or other video image data acquisition device immediately after acquiring the video data, or during post-processing of the video data at some time after acquiring the video data, to reduce the effects of unintended motion (jitter) of the hand-held devices by stabilizing the images. A processing circuit used to calculate an estimate of motion between components of successive image frames as part of a MPEG-4 or other compression algorithm is also used to estimate motion upon which the video data are altered to stabilize the images. The individual images may be pre-stabilized by using the results of stabilizing a prior image in order to reduce the amount of processing necessary to stabilize a current image.

Abstract: A method for removing blocking artifacts from moving and still pictures, comprising classifying horizontal and vertical boundaries in each picture as blocky or non-blocky; for each blocky boundary, defining an adaptive, picture contentdependent, one-dimensional filtered pixels region of interest (ROI) that crosses the boundary and is bound at each of its ends by a bounding pixel; defining a finite filter having a length correlated with the length of the ROI; defining a filtering pixels expansion that uniquely determines the padding values of the finite length filtered pixels ROI for the finite length filtering; and filtering the ROI pixels using the finite filter and the filtering expansion.

Abstract: Motion of an image of a scene being captured by a digital image acquisition device is detected and used to control parameters of illumination of the scene by a flash lamp that is typically built into the device. Parameters that may be controlled include the intensity, duration and timing of light emitted by the flash lamp. Such control of the flash illumination is preferably performed in conjunction with adjusting one or more exposure parameters used to capture an image. Such exposure parameters include duration, aperture and sensor gain. Motion blur caused by movement of the camera or by movement of an object within the scene being photographed is reduced by selecting appropriate exposure parameters and flash light characteristics.

Abstract: A phase measurement system for measuring phase between an input signal having a frequency and a reference signal having a substantially different frequency includes: a phase comparator having an output representing a time between a crossing of a first threshold by a clock derived from the reference signal and a predetermined time along an interval from a first sample to a second sample, where the input signal crosses a second threshold on the interval; an interpolator having an output indicative of an interpolated time of the second-threshold-crossing on the interval in the input signal; and a phase calculator which computes the phase difference by combining the phase comparator output and the interpolator output.

Abstract: According to one embodiment, a graphics/video processor includes a memory controller. The memory controller includes a first arbiter that receives memory client requests to access a memory device, and a first memory buffer coupled to the first arbiter. The first arbiter stores client requests that are selected by the first arbiter. The memory controller also includes a second arbiter coupled to the first memory buffer and a second memory buffer coupled to the second arbiter. The second arbiter receives requests from the memory client requests stored in the first memory buffer. The second memory buffer stores the client requests selected by the second arbiter. Further, the memory controller includes a third arbiter coupled to the second memory buffer. The third arbiter provides access of the memory device to the client requests stored in the second memory buffer.

Abstract: A system and method for determining an FFT window location for reception of an OFDM signal received over a transmission channel. The OFDM signal includes a plurality of symbols each having a guard interval. The system includes a correlation module that determines a location of maximum correlation in a first symbol, an FFT module to perform an FFT on the OFDM signal based upon an initial FFT window location, and an adjustment module. The adjustment module determines a plurality of permissible echo location options based upon the initial FFT window location, selects a permissible echo location option that corresponds most closely to the location of maximum correlation, and adjusts the initial FFT window location based upon the selected permissible echo location option so that the adjusted FFT window location includes substantially all of a useful symbol length of the first symbol while a maximum number of echoes are included within the guard interval of the first symbol.

Abstract: A method, apparatus, system and machine-readable medium for generating a composite output image based upon multiple input images. In certain embodiments, a plurality of input graphics images are iteratively blended in real time to provide a blended graphics image, which is then composited with other layers such as an input video image. The composite output image may then be provided to a display device. Iterative blending of the plurality of graphics images may include scaling, format conversion, and color space conversion, and may be performed based on priority information received for the graphics images from content sources. Compositing may include an alpha blending based on alpha values for pixels of the images.

Abstract: Methods for estimating illumination parameters under flickering lighting conditions are disclosed. Illumination parameters, such as phase and contrast, of a intensity-varying light source may be estimated by capturing a sequence of video images, either prior to or after a desired still image to be processed. The relative average light intensities of the adjacently-captured images are calculated and used to estimate the illumination parameters applicable to the desired still image. The estimated illumination parameters may be used to calculate the point spread function of a still image for image de-blurring processing. The estimated illumination parameters may also be used to synchronize the exposure timing of a still image to the time when there is the most light, as well as for use in motion estimation during view/video modes.

Abstract: A camera with auto-focusing performs multiple iterations in which the distance from the camera to an object is estimated for the purpose of auto-focusing the camera. Each estimate is made using depth-from-defocus with at least two images used to make the estimate. When the two images are taken, the camera parameters are different. For example, the focus position, aperture, or zoom may be different between the two images. In each subsequent iteration, the previous estimate of distance from the camera to the object is used so that the parameter varied (focus position or zoom) is closer to that corresponding to the estimated distance from the camera to the object, so that the estimated distance is closer to the actual distance in each iteration.

Abstract: A device for color shading correction is provided. Local color matching is performed as follows. For each pixel of the image that is being color matched, the RGB value is treated as a one-by-three matrix, which is multiplied by a three-by-three matrix that is generated during factory calibration. The matrix product is a one-by-three matrix that is used as the RGB value for the pixel in the color matched image.

Abstract: A camera that provides for a panorama mode of operation that employs internal software and internal acceleration hardware to stitch together two or more captured images to create a single panorama image with a wide format. Captured images are projected from rectilinear coordinates into cylindrical coordinates with the aid of image interpolation acceleration hardware. Matches are quickly determined between each pair of images with a block based search that employs motion estimation acceleration hardware. Transformation are found, utilizing regression and robust statistics techniques, to align the captured images with each other, which are applied to the images using the interpolation acceleration hardware. A determination is made for an optimal seam to stitch images together in the overlap region by finding a path which cuts through relatively non-noticeable regions so that the images can be stitched together into a single image with a wide panoramic effect.

Abstract: A unique method for chroma vertical upsampling used, for example, for conversion of the “4:2:0” format chroma information used in many applications of digital video, to the “4:2:2” or “4:4:4” format, is presented. This conversion is required so that video encoders can effect the display of this chroma information with a minimum of visible artifacts. The present invention carries out chroma vertical upsampling on a pixel by pixel basis. This chroma vertical upsampling is performed as a function of the amount of motion associated with each pixel as detected between 2 or more fields, and the field, frame and progressive sequence characteristics of the incoming video signal data.

Abstract: An automatic gain control (AGC) controls the signal amplitude at the input to an analog to digital converter (ADC) input by applying a gain that produces a desired overall amplitude resolution of the patterns actually presented by the signal delivered by the ADC converter. Short RLL patterns will have sufficient resolution for reliable extraction as a result of having sufficient overall amplitude, which thereby strengthens the ability of the read channel to correctly extract data. Moreover, the system determines correct AGC settings responsive to measurements of user data parameters. The system also detects and corrects for DC offsets in the signal whose gain is controlled.

Abstract: A calculating circuit and a method for generating an output signal representing an output number approximating an N-th root and/or a reciprocal of an input number represented by an input signal are described. The calculating circuit includes a subtractor circuit, an integrator circuit, and a multiplier circuit. The subtractor circuit responsive to a first signal and a feedback signal and configured for generating an error signal representing a difference between the first signal and the feedback signal. The integrator circuit responsive to the error signal and configured for computing the output signal. The multiplier circuit responsive to the output signal and configured for generating a feedback signal.