Secondary discrete cosine transform processing unit, a secondary discrete cosine transform method, an image coding apparatus and image coding method

摘要

PPROBLEM TO BE SOLVED: To perform coding by line memories fewer than before. PSOLUTION: A line memory 402 is configured with memories of seven lines. A level-dimensional cosine transform (DCT) apparatus 401 performs level-dimensional DCT processing in a unit of 8 pixels of horizontals about the image data from a scanner, and writes the processing result in all seven lines of the line memory 402.It readouts a level-dimensional DCT result for seven lines and inputs it into a vertical DCT apparatus 404 to sequential perpendicular direction from left of the line memory 402 via a multiplexer 403. The 8th line is encoded in a Huffman coding portion 405, and stored to a code data storage portion 406, after output of the level-dimensional DCT apparatus 401 via the multiplexer 403 is directly input into a vertical DCT apparatus 403. PCOPYRIGHT: (C)2004,JPO