| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To make the image quality of an image obtained by decoding substantially equal to that of an input image. <P>SOLUTION: In a method of decoding, compression encoding can be carried out while deterioration in image quality is prevented by generating difference value data from input image data, generating a discrete cosine conversion coefficient by performing discrete cosine conversion processing thereupon with arbitrary output bit precision, quantizing the discrete cosine conversion coefficient by extending and using a quantization scale based upon at least one of the output bit precision and input bit precision of the input image data, and then compressing and encoding the obtained quantization coefficient using a variable-length encoding table. Further, decoding can be carried out while deterioration in image quality is prevented by decoding the compressed and encoded quantization coefficient using the variable-length encoding table, and performing inverse quantization processing on the obtained quantization coefficient by extending and using the quantization scale based upon at least one of the input bit precision of the original input image data and output bit precision of the discrete cosine conversion coefficient. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
