Title:
IMAGE CODER AND IMAGE CODING METHOD
Document Type and Number:
Japanese Patent JP3648446
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide an image coder and its method employing prediction coding method and a pre-processing band limit that can decrease a prediction error without increasing quantization distortion, improve the coding efficiency and prevent a blurred decoded image and a motion vector providing a poor coding efficiency from being obtained.
SOLUTION: A motion compensation section 105 obtains a prediction error between a reference image and an input image to which a filter with a certain frequency characteristic is applied and a prediction error between the reference image and the input image to which other filter with a different frequency characteristic is applied in place of controlling the frequency characteristic of one filter, and a prediction error evaluation section 106 compares the prediction errors to adopt an input image whose prediction error is smaller for the input image. Thus, the prediction error is decreased, the coding efficiency is chanced, without increasing quantization distortion, and an edge blur of a decoded image can be prevented when many high frequency components are included around the edge of the reference image. Furthermore, the number of filters provided at a standby pre-filter section 112 is increased and different frequency characteristics are provided to them so as to prevent quantization distortion from being increased.
Inventors:
Hideaki Kizen
Yoshiyuki Yashima
Yoshiyuki Yashima
Application Number:
JP2000343120A
Publication Date:
May 18, 2005
Filing Date:
November 10, 2000
Export Citation:
Assignee:
Nippon Telegraph and Telephone Corporation
International Classes:
H04N19/50; H03M7/40; H04N19/102; H04N19/117; H04N19/136; H04N19/172; H04N19/196; H04N19/503; H04N19/51; H04N19/61; H04N19/625; H04N19/80; H04N19/85; H04N19/91; (IPC1-7): H04N7/32; H03M7/40
Domestic Patent References:
| JP9139922A | ||||
| JP9298753A | ||||
| JP2001245298A | ||||
| JP2001238209A | ||||
| JP200277909A |
Other References:
木全ほか,低ビットレート画像符号化におけるエッジ密度適応型前処理フィルタの一検討,電子情報通信学会2000年総合大会講演論文集,2000年 3月 7日,情報システム 2,P.24
Attorney, Agent or Firm:
Tsuyoshi Hashimoto