Abstract: Some embodiments of the invention provide a mobile device that captures and produces images with high dynamic ranges. To capture and produce a high dynamic range image, the mobile device of some embodiments includes novel image capture and processing modules. In some embodiments, the mobile device produces a high dynamic range (HDR) image by (1) having its image capture module rapidly capture a succession of images at different image exposure durations, and (2) having its image processing module composite these images to produce the HDR image.

Abstract: A method for transcoding from an MPEG-2 format to a VC-1 format is disclosed. The method generally comprises the steps of (A) decoding an input video stream in the MPEG-2 format to generate a picture; (B) determining a mode indicator for the picture; and (C) coding the picture into an output video stream in the VC-1 format using one of (i) a VC-1 field mode coding and (ii) a VC-1 frame mode coding as determined from the mode indicator.

Abstract: Some embodiments provide a method of aligning a pair of images. The method defines multiple different pairs of images at multiple different resolutions. The method hierarchically aligns the original pair of images by first aligning the pair of images at the lowest resolution and then aligning each pair of images at each higher resolution based on the alignments of the pair of images at the lower resolutions. For some of the resolutions, to perform the hierarchically alignment, the method identifies, for at least one image at each resolution, portions that are suitable for performing the alignment and portions that are not suitable for performing the alignment. The method compares each pair of images at a particular resolution by using the suitable portions while excluding the unsuitable portions from the comparison.

Abstract: Some embodiments provide a method of operating a device to capture an image of a high dynamic range (HDR) scene. Upon the device entering an HDR mode, the method captures and stores multiple images at a first image exposure level. Upon receiving a command to capture the HDR scene, the method captures a first image at a second image exposure level. The method selects a second image from the captured plurality of images. The method composites the first and second images to produce a composite image that captures the HDR scene. In some embodiments, the method captures multiple images at multiple different exposure levels.

Abstract: A method for transcoding from an MPEG-2 format to a VC-1 format is disclosed. The method generally comprises the steps of (A) decoding an input video stream in the MPEG-2 format to generate a picture; (B) determining a mode indicator for the picture; and (C) coding the picture into an output video stream in the VC-1 format using one of (i) a VC-1 field mode coding and (ii) a VC-1 frame mode coding as determined from the mode indicator.

Abstract: An encoder circuit, a task scheduler circuit and a decoder circuit. The encoder circuit may be configured to (i) generate one or more first status signals in response to one or more report signals and (ii) perform video encoding tasks based on available central processing unit (CPU) cycles and memory bandwidth. The task scheduler circuit may be configured to (i) generate a control signal and the one or more report signals in response to the one or more first status signals. The decoder circuit may be configured to (i) generate one or more second status signals and (ii) perform concurrent decoding while the encoder circuit performs adaptive video encoding tasks in response to the control signal.

Abstract: A method for implementing B-frame prediction in video compression comprising the steps of (A) setting a prediction flag (i) “off” if B-frames are used for block prediction and (ii) “on” if B-frames are not used for block prediction, (B) if the prediction flag is off, generating an output video signal in response to an input video signal by performing an inverse quantization step and an inverse transform step in accordance with a predefined coding specification and (C) if the prediction flag is on, bypassing the inverse quantization step and the inverse transform step.

Abstract: A method for transcoding from a VC-1 format to an MPEG-2 format is disclosed. The method generally comprises the steps of (A) decoding an input video stream in the VC-1 format to generate a picture; (B) determining a first mode indicator for the picture; and (C) coding the picture into an output video stream in the MPEG-2 format using one of (i) an MPEG-2 field mode coding and (ii) an MPEG-2 frame mode coding as determined from the first mode indicator.

Abstract: A method for coefficient bitdepth limitation in an encoder and/or bitstream generation apparatus including the steps of (A) generating one or more residual block coefficients in response to a video signal and one or more coding parameters and (B) manipulating the one or more coding parameters such that the one or more residual block coefficients are prevented from having values greater than a bitdepth of the video signal plus a predefined number of bits.

Abstract: A method for deinterlacing a picture is disclosed. The method generally includes the steps of (A) generating a plurality of primary scores by searching along a plurality of primary angles for an edge in the picture proximate a location interlaced with a field of the picture, (B) generating a plurality of neighbor scores by searching for the edge along a plurality of neighbor angles proximate a particular angle of the primary angles corresponding to a particular score of the primary scores having a best value and (C) identifying a best score from a group of scores consisting of the particular score and the neighbor scores to generate an interpolated sample at the location.

Abstract: Various techniques for lens shading correction are provided. In one embodiment, the location of a current pixel is determined relative to a gain grid having a plurality of grid points distributed in horizontal and vertical directions. If the location of the current pixel corresponds to a grid point, a lens shading gain associated with that grid point is applied to the current pixel. If the location of the current pixel is between four grid points, bi-linear interpolation is applied to the four grid points to determine an interpolated lens shading gain. In another embodiment, a radial gain grid may be provided, and lens shading gains may be interpolated based upon grid points neighboring a current pixel in the radial and angular directions. In a further embodiment, a radial lens shading gain is determined by determining a radial distance from the center of the image to the current pixel and multiplying the radial distance by a global gain parameter based upon the color of the current pixel.

Abstract: Various techniques are provided for the detection and correction of defective pixels in an image sensor. In accordance with one embodiment, a static defect table storing the locations of known static defects is provided, and the location of a current pixel is compared to the static defect table. If the location of the current pixel is found in the static defect table, the current pixel is identified as a static defect and is corrected using the value of the previous pixel of the same color. If the current pixel is not identified as a static defect, a dynamic defect detection process includes comparing pixel-to-pixel gradients between the current pixel a set of neighboring pixels against a dynamic defect threshold. If a dynamic defect is detected, a replacement value for correcting the dynamic defect may be determined by interpolating the value of two neighboring pixels on opposite sides of the current pixel in a direction exhibiting the smallest gradient.

Abstract: Various techniques are provided herein for processing raw image data in front-end processing logic of an image signal processing system. In one embodiment, the front-end processing logic includes a statistics processing unit configured to process raw image data acquired by an image sensor to obtain one or more sets of statistics. The statistics processing unit may first correct defective pixels in the raw image data and then correct lens shading errors in the raw image data prior to extracting the statistics information. In certain embodiments, black level compensation may be applied between the defective pixel correction and lens shading correction steps, and inverse black level compensation may be applied between the lens shading correction step and the extraction of the statistics information. The acquired statistics information may be utilized by an image signal processing pipeline for converting the raw image data into a color (e.g., RGB) and/or luma (e.g., YCbCr) image.

Abstract: Various techniques relating to image sharpening are provided. In one embodiment, a luminance image is obtained based upon image data acquired by an image sensor. A multi-scale unsharp mask, which may include at least two Gaussian filters of difference radii, is applied to the luminance image to determine a plurality of unsharp values. Each of the unsharp values may be compared to a corresponding threshold and, for the unsharp values that exceed their respective thresholds, the unsharp value is multiplied by a corresponding gain and added to a base image, which may be selected as the luminance image or the output of one of the Gaussian filters. Each gained unsharp value may be summed with the base image to produce a final sharpened output. In some embodiments, an attenuated gain may be applied to unsharp values that do not exceed their respective thresholds.

Abstract: Various techniques for temporally filtering raw image data acquired by an image sensor are provided. In one embodiment, a temporal filter determines a spatial location of a current pixel and identifies at least one collocated reference pixel from a previous frame. A motion delta value is determined based at least partially upon the current pixel and its collocated reference pixel. Next, an index is determined based upon the motion delta value and a motion history value corresponding to the spatial location of the current pixel, but from the previous frame. Using the index, a first filtering coefficient may be selected from a motion table. After selecting the first filtering coefficient, an attenuation factor may be selected from a luma table based upon the value of the current pixel, and a second filtering coefficient may subsequently be determined based upon the selected attenuation factor and the first filtering coefficient.

Abstract: An apparatus including a first circuit and a second circuit. The first circuit may be configured to perform image signal processing using encoding related information. The second circuit may be configured to encode image data using image signal processing related information, wherein said first circuit is further configured to pass said image signal processing related information to said second circuit and said second circuit is further configured to pass said encoding related information to said first circuit.

Abstract: Various techniques are provided herein for the demosaicing of images acquired and processed by an imaging system. The imaging system includes an image signal processor and image sensors utilizing color filter arrays (CFA) for acquiring red, green, and blue color data using one pixel array. In one embodiment, the CFA may include a Bayer pattern. During image signal processing, demosaicing may be applied to interpolate missing color samples from the raw image pattern. In one embodiment, interpolation for the green color channel may include employing edge-adaptive filters with weighted gradients of horizontal and vertical filtered values. The red and blue color channels may be interpolated using color difference samples with co-located interpolated values of the green color channel. In another embodiment, interpolation of the red and blue color channels may be performed using color ratios (e.g., versus color difference data).

Abstract: Various techniques are provided herein for processing raw image data acquired using a digital image sensor in an image processing pipeline of an image signal processing system. In one embodiment, the image processing pipeline may first process the raw image data (e.g., Bayer image data) for the detection and correction of defective pixels. Next, the image processing pipeline may process the raw image data to reduce noise. Thereafter, the image processing pipeline may correct lens shading distortion in the raw image data and, subsequently, apply a demosaicing algorithm to convert the raw image data into full color image data (e.g., RGB image data). The color image data may be further processed by the image processing pipeline to correct color and gamma properties prior to being converted into a luma and chroma color space (e.g., YCbCr color space).

Abstract: Systems and methods may employ separate image sensors for collecting different types of data. In one embodiment, separate luma, chroma and 3-D image sensors may be used. The systems and methods may involve generating an alignment transform for the image sensors, and using the 3-D data from the 3-D image sensor to process disparity compensation. The systems and methods may involve image sensing, capture, processing, rendering and/or generating images. For example, one embodiment may provide an imaging system, including: a first image sensor configured to obtain luminance data of a scene; a second image sensor configured to obtain chrominance data of the scene; a third image sensor configured to obtain three-dimensional data of the scene; and an image processor configured to receive the luminance, chrominance and three-dimensional data and to generate a composite image corresponding to the scene from that data.

Abstract: A method for transcoding from a VC-1 format to an MPEG-2 format is disclosed. The method generally comprises the steps of (A) decoding an input video stream in the VC-1 format to generate a picture; (B) determining a first mode indicator for the picture; and (C) coding the picture into an output video stream in the MPEG-2 format using one of (i) an MPEG-2 field mode coding and (ii) an MPEG-2 frame mode coding as determined from the first mode indicator.