Apple Inc.

Yu Tina Tian

Hsi-Jung Wu

Ke-Chiang C Chu

Jian Lu

In a digital signal processing system, a method for selecting a transform function to apply to an input signal based on characteristics of the signal, and for self-adjusting criteria which are used in selecting a transform function to apply to a subsequent signal. Characteristics are obtained from the signal. The characteristics are compared to adjustable criteria which are used in selecting a transform function. Differing criteria are maintained for the different selectable transform functions. A record is maintained of transform functions selected and the particular characteristics that caused the selection. Based on the ability of a transform function to minimally define the coded signal, an inverse transform function is selected to decode the signal. The criteria used in selecting a transform function to apply to a subsequent signal are adjusted based on a quality measure of the decoded signal and the record of selected transform functions.

Digital image coding system having self-adjusting selection criteria for selecting a transform function

A system and method using edge processing to remove blocking artifacts comprises an edge processor having an image converter for building an edge representation of a received image, a statistics analyzer for compiling a histogram containing edge intensities of the edge representation, a reference calculator for using the histogram to compute reference values corresponding to the blocking artifacts and an artifact remover for identifying and removing the blocking artifacts using the computed reference values.

System and method using edge processing to remove blocking artifacts from decompressed images

Digital image coding system having self-adjusting selection criteria for

A system for estimating block motion from a previous frame to a current frame, wherein motion vectors have been computed for blocks in the previous frame. The system comprises a P-checkerboard processor, an S-checkerboard processor and a block matching engine. The a P-checkerboard processor selects a first current block from a primary checkerboard pattern, retrieves motion vectors for reference blocks in the previous frame, and uses the retrieved motion vectors to generate a temporal search window. The block matching engine locates in the temporal search window a block which best matches the first current block, and determines the current motion vector from the best matching block to the first current block. Alternatively, the a P-checkerboard processor can use the retrieved motion vectors to interpolate the current motion vector. The S-checkerboard processor selects a second current block from a secondary checkerboard pattern, and uses the current motion vector to generate a spatial dynamic search window. The block matching processor locates in the spatial search window the block which best matches the second current block, and determines the current motion vector from the best matching block to the second current block.

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Stanford, CA, United States of America

Yu Tina Tian