| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To enable Huffman coding using a common Huffman table, according to the basic quantization value Q<SB>i,j</SB>, and to control increase in the capacity of Huffman table, even when the image data expressed by n-bit within the range from L to K are coded by the JPEG-coding method. <P>SOLUTION: A basic quantization table storing unit 220 stores the quantization step values Q<SB>00</SB>to Q<SB>77</SB>, which are used for the baseline JPEG coding. A minimum quantization step generating unit 221 outputs the minimum quantization step value Q<SB>n_min</SB>, according to the number of bits n of each color element of the image data as the coding object. A comparing and selecting unit 222 compares the quantization step values Q<SB>00</SB>to Q<SB>77</SB>with Q<SB>n_min</SB>and selects the larger one to output the result to the quantization unit 209 as Q'<SB>i,j</SB>. A quantization unit 209 stores Q'<SB>i,j</SB>to the quantization table storing unit 209a for quantizing the orthogonal transformation coefficient outputted from a DCT conversion unit 207. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
