Patent ID: 7916959

Claim:
An image decoding method for decoding coded picture data which is derived from: dividing a matrix of image signal into blocks of different sizes; performing an orthogonal transform on the respective blocks; reading resultant orthogonal transform coefficients into strings of transform coefficients while arranging a single string of transform coefficients from a block larger than a block of a minimum size into shorter strings of transform coefficients each having a length equal to that of a string of transform coefficients from the minimum size block; and entropy-coding the respective strings of transform coefficients, the image decoding method comprising: entropy-decoding the coded picture data to derive the strings of entropy-decoded transform coefficients; combining the shorter strings of entropy-decoded transform coefficients back into the single string of entropy-decoded transform coefficients; and performing an inverse orthogonal transform on the single string of entropy-decoded transform coefficients in order to reproduce the matrix of image signal; wherein the coded picture data comprises entropy-coded data representing strings of sixteen (16) transform coefficients obtained by interleaving, from a lower frequency coefficient, sixty four (64) transform coefficients of an orthogonally transformed 8x8 block to produce four (4) strings of sixteen (16) transform coefficients, wherein entropy-decoding the coded picture data comprises entropy-decoding the entropy-coded data of the respective strings of sixteen (16) transform coefficients, wherein combining the shorter strings of entropy-decoded transform coefficients comprises de-interleaving, from a lower frequency coefficient, sixty four (64) transform coefficients from the four (4) strings of sixteen (16) transform coefficients to reconstruct the single string consisting of the sixty four (64) transform coefficients of the orthogonally transformed 8x8 block, and wherein performing an inverse orthogonal transform comprises performing an inverse orthogonal transform on the sixty four (64) transform coefficients of the orthogonally transformed 8x8 block.