Title:
IMAGE COMPRESSION CODER
Document Type and Number:
Japanese Patent JP3115199
Kind Code:
B2
Abstract:
PURPOSE: To improve the accuracy of code quantity control by calculating a code quantity when an output of a 2nd quantizer is subjected to variable coding and deciding a quantization table to adopt a prescribed code quantity for one image based on the result of calculation.
CONSTITUTION: A DCT coefficient for each block outputted from a DC transformation circuit 3 is inputted to a quantizer 9, in which M-ways of scale factors α1-αM are assigned so that each block for one field has the same scale factor. Then each DCT coefficient is linearly quantized in a quantization table where the scale factors α1-αM and quantization steps are multiplied. A block code calculation circuit 12 calculates a code multi-value processing per block of variable length data when the quantized DCT coefficient is coded. A code quantity controller 80 predicts the code quantity based on M-ways of quantization table for one image according to the result of calculation and decides a quantization table to form a prescribed code quantity for one image pattern. The controller 80 outputs the decided code quantity to the quantizer 5.
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Inventors:
Hideaki Mita
Tatsushi Sakauchi
Tatsushi Sakauchi
Application Number:
JP31280894A
Publication Date:
December 04, 2000
Filing Date:
December 16, 1994
Export Citation:
Assignee:
Matsushita Electric Industrial Co., Ltd
International Classes:
H04N11/04; G06T9/00; H03M7/30; H04N19/126; H04N19/136; H04N19/14; H04N19/149; H04N19/189; H04N19/196; H04N19/423; H04N19/60; H04N19/625; H04N19/85; H04N19/88; H04N19/91; (IPC1-7): H04N7/30; G06T9/00; H03M7/30; H04N11/04
Domestic Patent References:
| JP7298194A | ||||
| JP5316362A | ||||
| JP4278261A | ||||
| JP2224484A | ||||
| JP556276A |
Attorney, Agent or Firm:
Yoshihiro Morimoto
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