| 摘要 |
PROBLEM TO BE SOLVED: To modify stepwise a degree of scrambling applied to an input image. SOLUTION: A coding section 5 in the image coder encodes a DCT(discrete cosine transform) coefficient quantized by a quantization section 4. In this case, a key memory section 14 stores whether or not a macro block is encrypted for each macro block. Then a coding procedure setting section 13 instructs it to the coding section 5 as to whether a macro block being a current coding processing object is to be encrypted or the conventional coding is applied to the macro block according to the encryption key stored in the key memory section 14. |
