Patent ID: 6643408
Filing Date: 2003-11-04
Classification: G06T

Abstract:
An image coding apparatus for compressing and coding image data by generating an entropy code from a coefficient relating to the image data, the entropy code being a bit pattern of which bit length is variable depending on occurrence probability of the coefficient, the image coding apparatus comprising:a coding table containing entry information showing an entropy code corresponding to a coefficient, the entry information including compressed information generated by run-length compressing a part of the entropy code; an obtaining unit operable to obtain, from the coding table, entry information corresponding to the coefficient; a run generating unit operable to run-length decode the compressed information included in the obtained entry information; and a code generating unit operable to generate, based on the obtained entry information and the run-length decoded information, a bit pattern as an entropy code corresponding to the coefficient, wherein the entry information contained in the coding table includes uncompressed information besides the compressed information, the compressed information shows a bit length of the run-length of the run-length compressed part, the uncompressed information shows a bit pattern of another part of the entropy code aside from the run-length compressed part, the run generating unit run-length decodes the compressed information by generating a run having the bit length shown by the compressed information, and the code generating unit generates the entropy code using the generated run and the uncompressed information that is included in the entry information.