Patent ID: 6577681
Filing Date: 2003-06-10
Classification: H04N

Abstract:
An image coding apparatus, comprising:an image splitting unit that splits an input image; an orthogonal transformation unit that orthogonally transforms images split by said image splitting unit; a quantization step width control information output unit that outputs one or more types of quantization step width control information of said split images; a DC differential signal calculating unit that calculates a difference between a DC signal of signals orthogonally transformed by said orthogonal transformation unit and a DC signal of a split image split immediately before; and a DC differential signal and quantization step width control information coding unit that codes said DC differential signal and said one or more types of quantization step width control information, wherein said DC differential signal and quantization step width control information coding unit changes the code of said DC differential signal and at least one predetermined code of the respective codes of said one or more types of quantization step width control information in accordance with the value of said DC differential signal and at least one of the values of said one or more types of quantization step width control information which is not corresponding to said predetermined code(s).