| 摘要 |
<P>PROBLEM TO BE SOLVED: To disable copying a data with maintained good quality using the data before copying without degrading output quality. <P>SOLUTION: A subtractor 147 subtracts, block by block, the minimum value MIN of a block of interest from the image data of the block, and obtains a minimum value elimination data PDI. A quantizing circuit 148 quantizes the minimum value elimination data PDI by a quantizing step determined depending on a dynamic range DR, and obtains a code signal DT as an encoded data. In this case, the quantizing circuit 148 quantizes by setting the quantizing step in at least one area out of the maximum value MAX side and the minimum value MIN side greater than the quantizing step in the other area. Through the above encoding and decoding, the dynamic range is greatly decreased, and thus image quality becomes greatly deteriorated. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
