Patent EP0220706A2 successfully refreshed from Google Patents.
EP0220706A2
Expired / Lapsed
EP
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Method for image data coding
Assignee: Hitachi Ltd
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Filing: 1986-10-27
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Granted: —
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Expires: 2006-10-27
Abstract
Abstract To efficiently compress image data, the image data is divided into rectangular blocks of non-equal length in a hierarchal structure in accordance with a brightness change, and is encoded into tree-structure data for each of the divided blocks so that the mean distortion of the image data inside each block does not exceed an allowable value.
Inventors
- 👤 Shinichiro Miyaoka
- 👤 Ryoichi Sasaki
- 👤 Takayoshi Shiraishi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 22:00
CPC Classifications
H; H04; H04N; H04N19/00; H04N19/90; H04N19/96; G; G06; G06T; G06T9/00; G06T9/40
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
60 words
A method of encoding image data characterized in that said image data are divided into rectangular blocks of non-equal length in accordance with the degree of a brightness change, and said image data inside said block is encoded in a tree structure so that the index of mean distortion in each of said blocks does not exceed an allowable value.
Claim 2
Independent Claim
60 words
A method of encoding image data characterized in that said image data are divided into rectangular blocks of non-equal length in accordance with the degree of a brightness change, and said image data inside said block is encoded in a tree structure so that the index of mean distortion in each of said blocks does not exceed an allowable value.
Claim 3
Dependent Claim
45 words
The method of encoding image data as defined in claim 1 wherein the portion of said rectangular block of the non-equal length having a gentle brightness change is divided into great blocks while its portion having a steep brightness change is divided into small blocks.
Claim 4
Dependent Claim
34 words
The method of encoding image data as defined in claim 1 wherein a mean square error of brightness of pixels inside each of said blocks is used as said index of said mean distortion.
Claim 5
Dependent Claim
40 words
The method of encoding image data as defined in claim 1 wherein said image data inside each of said blocks is encoded to data having a tree structure by use of the mean brightness and brightness slope of said data.
References Cited (Backward Citations)
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