EP0466475A2
Expired / Lapsed
EP
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An image data encoding system
Assignee: Fujitsu Ltd
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Filing: 1991-07-10
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Granted: —
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Expires: 2011-07-10
Abstract
Abstract An image data encoding system efficiently reconstructs an image through a progressive image buildup in stages. An original image is divided into blocks each having NXN picture elements, whose transformation coefficients are obtained by orthogonal transformations on their graduated values. The image data encoding system has a transformation coefficient memory (61) for storing transformation coefficients; a mask information memory (62) for storing mask information for masking transformation coefficients; a masker (63) for masking the most significant bits of the transformation coefficients specified by mask information; a shift information memory storing quantization thresholds for quantizing the transformation coefficients; and a quantizer (65) for quantizing the masked transformation coefficients per the quantization threshold. The quantization threshold can be given a value of 2 to an integer power, and quantization can be attained by shifting bits of the transformation coefficients towards less significant bits by that power.
Inventors
- 👤 Tsugio Noda
- 👤 Masahiro Fukuda
- 👤 Kimitaka Murashita
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 22:45
CPC Classifications
H; H04; H04N; H04N19/00; H04N19/50; H04N19/59; H04N19/10; H04N19/102; H04N19/124; H04N19/126; H04N19/132; H04N19/169; H04N19/17; H04N19/176; H04N19/18; H04N19/30; H04N19/60
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
109 words
An image data encoding method comprising: a step of dividing an original image into a plurality of blocks respectively comprising NXN picture elements; a step of obtaining transformation coefficients by performing orthogonal transformations on the graduated values of said NXN picture elements in the respective ones of said plurality of blocks; a step of masking the most significant bits of said transformation coefficients, the number of said most significant bits being specified by received mask information; and a step of quantizing NXN transformation coefficients in said plurality of blocks by a threshold having values of 2 to an integer power with the power being specified by received shift information.
Claim 2
Dependent Claim
25 words
The image data encoding method according to claim 1, wherein: said step of quantizing NXN transformation coefficients are performed by shifting bits by said power.
Claim 3
Dependent Claim
140 words
An image data encoding method comprising: a step of dividing an original image into a plurality of blocks respectively comprising NXN picture elements; a step of obtaining transformation coefficients by performing orthogonal transformations on the graduated values of said NXN picture elements in the respective ones of said plurality of blocks; a step of quantizing NXN transformation coefficients in said plurality of blocks by a first threshold having values of 2 to an integer power in a first stage; a step of masking the most significant bits of said transformation coefficients, the number of said most significant bits being specified by received mask information in later stages; and a step of quantizing said NXN transformation coefficients in said plurality of blocks by a respective threshold for each of said later stages being specified by received shift information in later stages.
Claim 4
Dependent Claim
29 words
The image data encoding method according to claim 3, wherein: said step of quantizing NXN transformation coefficients are performed by shifting bits by said power expressing said respective threshold.
Claim 5
Dependent Claim
112 words
An image data encoding apparatus: dividing an original image into a plurality of blocks respectively comprising NXN picture elements; obtaining transformation coefficients by performing orthogonal transformations on the graduated values of said NXN picture elements in the respective ones of said plurality of blocks: said image data encoding apparatus comprising: a transformation coefficient memory means for storing received transformation coefficients; a mask means for masking the most significant bits of said transformation coefficients memorized in said transformation coefficient memory means, the number of said most significant bits being specified by received mask information; and a quantization means for quantizing said transformation coefficients masked by said mask means according to a quantization threshold.
Claim 6
Dependent Claim
38 words
The image data encoding apparatus according to claim 5, wherein: said quantization threshold has a value of 2 to an integer power; said quantizing means shifts bits of said transformation coefficients towards less significant bits by said power.
Claim 7
Dependent Claim
163 words
An image data encoding apparatus: dividing an original image into a plurality of blocks respectively comprising NXN picture elements; obtaining transformation coefficients by performing orthogonal transformations on the graduated values of said NXN picture elements in the respective ones of said plurality of blocks: said image data encoding apparatus comprising: a transformation coefficient memory means for memorizing received transformation coefficients; a mask information memory means for memorizing NXN pieces of mask information for masking NXN transformation coefficients respectively in said plurality of blocks; a mask means for masking the most significant bits of said transformation coefficients memorized in said transformation coefficient memory means, the number of said most significant bits being specified by received mask information; a quantization threshold memory means memorizing NXN quantization thresholds for quantizing said NXN transformation coefficients respectively in said plurality of blocks; and a quantization means for quantizing said transformation coefficients masked by said mask means according to the quantization threshold memorized in said quantization threshold memory means.
Claim 8
Dependent Claim
46 words
The image data encoding apparatus according to claim 7, further comprising: a control means for controlling the operations of said quantization means and disabling said mask means in a first stage and the operations of said mask means and said quantization means after said first stage.
Claim 9
Dependent Claim
36 words
The image data encoding apparatus according to claim 8, wherein: said mask information stored said mask information memory means and said quantization threshold stored in said quantization threshold memory means are changed according to said stages.
References Cited (Backward Citations)
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