US4797945A
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Image data coding apparatus
Assignee: Canon Inc
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Filing: 1986-12-11
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Granted: 1989-01-10
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Expires: 2006-12-11
Abstract
Abstract An image data coding apparatus adopting the method of this invention includes a divider section for dividing an image having gray levels into a plurality of blocks, each consisting of a plurality of pixels; a pre-processing section for detecting the density and the presence/absence of an edge in an image of each divided block; and a vector quantizing section for encoding an image of each block in accordance with the detected density and the presence/absence of the edge in the image of the block. The pre-processing section detects a standard deviation of density levels of the pixels included in each block. The vector quantizing section divides the density levels of the pixels included in each block into a plurality of level sections so as to obtain a code indicating the level section in which the density level of each pixel is included. In the vector quantizing section, the obtained code is again encoded by means of vector quantization.
Inventors
- 👤 Yoshiyuki Suzuki
- 👤 Masahiro Funada
- 👤 Mamoru Sato
- 👤 Yukio Sato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 04:31
CPC Classifications
H; H04; H04N; H04N19/00; H04N19/90; H04N19/94; G; G06; G06T; G06T9/00; G06T9/008
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
61 words
An image data coding method comprising the steps of: dividing an image having gray levels into a plurality of blocks, each consisting of a plurality of pixels; detecting a density and the presence/absence of an edge in each block; and encoding an image of each block in accordance with the detected density and the presence/absence of the edge in the image.
Claim 2
Dependent Claim
61 words
An image data coding method comprising the steps of: dividing an image having gray levels into a plurality of blocks, each consisting of a plurality of pixels; detecting a density and the presence/absence of an edge in each block; and encoding an image of each block in accordance with the detected density and the presence/absence of the edge in the image.
Claim 3
Dependent Claim
35 words
A method according to claim 1, wherein, in said detection step, the density of the image is detected by calculating an average value of density levels of a plurality of pixels included in each block.
Claim 4
Dependent Claim
34 words
A method according to claim 1, wherein, in said detection step, the presence/absence of the edge is detected by calculating a contrast of density levels of a plurality of pixels included in each block.
Claim 5
Dependent Claim
31 words
A method according to claim 3, wherein said detection step comprises the step of calculating a standard deviation of the densty levels of a plurality of pixels included in each block.
Claim 6
Dependent Claim
50 words
A method according to claim 1, wherein, in said encoding step, density levels of a plurality of pixels included in each block are divided into a plurality of level sections so as to obtain a code indicating the level section in which the density level of each pixel is included.
Claim 7
Dependent Claim
52 words
A method according to claim 5, wherein, in said encoding step, dividing points for dividing the density levels of the plurality of pixels included in each block into the plurality of level sections are determined in accordance with the density and the presence/absence of the edge in the image of the block.
Claim 8
Dependent Claim
24 words
A method according to claim 1, further comprising the step of performing second encoding with respect to a code obtained by said encoding step.
Claim 9
Dependent Claim
15 words
A method according to claim 7, wherein said second encoding is performed by vector quantization.
Claim 10
Dependent Claim
68 words
An image data coding apparatus comprising: means for dividing an image having gray levels into a plurality of blocks, each consisting of a plurality of pixels; means for detecting a density and the presence/absence of an edge in an image of the divided block; and means for encoding an image of the block in accordance with the detected density and the presence/absence of the edge in the image.
Claim 11
Dependent Claim
68 words
An image data coding apparatus comprising: means for dividing an image having gray levels into a plurality of blocks, each consisting of a plurality of pixels; means for detecting a density and the presence/absence of an edge in an image of the divided block; and means for encoding an image of the block in accordance with the detected density and the presence/absence of the edge in the image.
Claim 12
Dependent Claim
32 words
An apparatus according to claim 9, wherein said detection means detects the density of the image.by calculating an average value of density levels of a plurality of pixels included in each block.
Claim 13
Dependent Claim
33 words
An apparatus according to claim 9, wherein said detection means detects the presence/absence of the edge by calculating a contrast value of density levels of a plurality of pixels included in each block.
Claim 14
Dependent Claim
27 words
An apparatus according to claim 11, wherein said detection means calculates a standard deviation of the density levels of a plurality of pixels included in each block.
Claim 15
Dependent Claim
48 words
An apparatus according to claim 9, wherein said encoding means divides density levels of a plurality of pixels included in each block into a plurality of level sections so as to obtain a code indicating the level section in which the density level of each pixel is included.
Claim 16
Dependent Claim
50 words
An apparatus according to claim 13, wherein said encoding means determines dividing points for dividing the density levels of the plurality of pixels included in each block into the plurality of level sections in accordance with the density and the presence/absence of the edge in the image of the block.
Claim 17
Dependent Claim
25 words
An apparatus according to claim 9, further comprising second encoding means for performing second encoding with respect to a code obtained by said encoding means.
Claim 18
Dependent Claim
20 words
An apparatus according to claim 15, wherein said second encoding means performs the second encoding by means of vector quantization.
Claim 19
Dependent Claim
94 words
An image data coding method comprising the steps of: dividing an image having gray levels into a plurality of blocks, each consisting of a plurality of pixels; detecting an edge in an image of the divided block; performing first quantization by means of vector quantization in accordance with the detected edge; extracting pixels of interest from each block consisting of a plurality of pixels in accordance with a reproduced pattern obtained by the first quantization; and performing second quantization of a block consisting of the extracted pixels of interest by means of vector quantization.
Claim 20
Dependent Claim
94 words
An image data coding method comprising the steps of: dividing an image having gray levels into a plurality of blocks, each consisting of a plurality of pixels; detecting an edge in an image of the divided block; performing first quantization by means of vector quantization in accordance with the detected edge; extracting pixels of interest from each block consisting of a plurality of pixels in accordance with a reproduced pattern obtained by the first quantization; and performing second quantization of a block consisting of the extracted pixels of interest by means of vector quantization.
Claim 21
Dependent Claim
28 words
A method according to claim 17, wherein, in said second quantization step, vector quantization is performed using pixels other than the pixels of interest as a fixed value.
Claim 22
Dependent Claim
21 words
A method according to claim 17, further comprising the step of combining codes obtained by said first and second quantization steps.
Claim 23
Dependent Claim
28 words
A method according to claim 17, wherein, in said detection step, image levels of a plurality of pixels included in each block are binarized to detect the edge.
Claim 24
Dependent Claim
86 words
An image data coding apparatus comprising: means for dividing an image having gray levels into a plurality of blocks, each consisting of a plurality of pixels; means for detecting an edge in an image of the divided block; first quantization means for performing vector quantization in accordance with the detected edge; means for extracting pixels of interest from a plurality of pixels in accordance with a reproduced pattern obtained by quantization; and second quantization means for vector-quantizing a block consisting of the extracted pixels of interest.
Claim 25
Dependent Claim
86 words
An image data coding apparatus comprising: means for dividing an image having gray levels into a plurality of blocks, each consisting of a plurality of pixels; means for detecting an edge in an image of the divided block; first quantization means for performing vector quantization in accordance with the detected edge; means for extracting pixels of interest from a plurality of pixels in accordance with a reproduced pattern obtained by quantization; and second quantization means for vector-quantizing a block consisting of the extracted pixels of interest.
Claim 26
Dependent Claim
26 words
An apparatus according to claim 21, wherein said second quantization means performs vector quantization using pixels other than the pixels of interest as a fixed value.
Claim 27
Dependent Claim
22 words
An apparatus according to claim 21, further comprising means for combining and outputting codes obtained by said first and second quantization means.
Claim 28
Dependent Claim
28 words
An apparatus according to claim 21, wherein said detection means binarizes image levels of a plurality of pixels included in each block so as to detect the edge.
Claim 29
Dependent Claim
56 words
An image data coding method comprising the steps of: dividing an image having gray levels into a plurality of blocks, each consisting of a plurality of pixels; first-encoding the divided block in accordance with an image density and the presence/absence of an edge in the block; and second-encoding the first-encoded block by means of vector quantization.
Claim 30
Dependent Claim
56 words
An image data coding method comprising the steps of: dividing an image having gray levels into a plurality of blocks, each consisting of a plurality of pixels; first-encoding the divided block in accordance with an image density and the presence/absence of an edge in the block; and second-encoding the first-encoded block by means of vector quantization.
Claim 31
Dependent Claim
36 words
A method according to claim 25, wherein, in said first-encoding step, encoding is performed in accordance with an average value of density levels and an image contrast of a plurality of pixels included in each block.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-01-10 | 1992-07-11 | 1993-01-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-01-10 | 1996-07-11 | 1997-01-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-01-10 | 2000-07-11 | 2001-01-10 | $7700.00 | Window Closed / Lapsed |