Image compression device for realizing high-speed and high-accuracy coding

Application Number: 00108319
Application Date: 2000.03.23
Publication Number: 1273491
Publication Date: 2000.11.15
Priority Information: 1999/8/3 JP 219957/99; 1999/3/23 JP 78206/99
International: H03M7/42;H04N7/24
Applicant(s) Name: Sanyo Electric Co., Ltd.
Inventor(s) Name: Okada Shigeyuki
Patent Agency Code: 72001
Patent Agent: ye kaidong
Abstract The data transfer is repeatedly performed through a path constituted of an image holding RAM->a Huffman decoding circuit->an inverse quantization circuit->a quantization circuit->a Huffman encoding circuit until a code amount of compression image data generated by the Huffman encoding circuit becomes equal to or smaller than a maximum value determined according to an image quality, and thus a quantization threshold value and a Huffman code are determined. Every time the process is repeated, the quantization threshold value stored in a table of a first RAM and a Huffman code stored in a table of a second RAM corresponding to the quantization circuit and the Huffman encoding circuit, respectively, are newly set to a slightly higher value. As a quantization threshold value to be set in a table of a third RAM corresponding to the inverse quantization circuit, a quantization threshold value set in the first RAM at the previous quantization is used. As a Huffman code to be set in a table of a fourth RAM corresponding to the Huffman decoding circuit, a Huffman code set in the second RAM at a previous variable length encoding is used.