Patent ID: 6532309
Filing Date: 2003-03-11
Classification: G06T,H04N

Abstract:
A picture decoding apparatus for decoding, from compressed picture data of a first resolution, moving picture data of a second resolution lower than said first resolution, said compressed picture data of the first resolution having been obtained by predictive coding by performing motion prediction in terms of a pre-set pixel block (macro-block) as a unit and orthogonal transform in terms of a pre-set pixel block (macro-block) as a unit, comprising:first inverse orthogonal transform means for inverse orthogonal transforming an orthogonal transform block of said compressed picture data, obtained on orthogonal transforming in accordance with an orthogonal transform system associated with interlaced scanning (field orthogonal transform mode); and second inverse orthogonal transform means for inverse orthogonal transforming an orthogonal transform block of said compressed picture data, obtained on orthogonal transforming in accordance with an orthogonal transform system associated with sequential scanning (frame orthogonal transform mode); said second inverse orthogonal transform means setting certain coefficients of the frequency components in the vertical direction of said orthogonal transform block to zero, inverse orthogonal transforming the coefficients of the totality of the frequency components of the orthogonal transform block, certain coefficients of which have been set to 0, separating pixels of the inverse orthogonal transformed orthogonal transform block into two pixel blocks associated with interlaced scanning, orthogonal transforming the separated two pixel blocks, inverse orthogonal transforming the coefficients of low frequency components of the orthogonal transformed two pixel blocks and synthesizing the two inverse orthogonal transformed pixel blocks to generate an orthogonal transform block.