US6546145B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Image compression using selection of quantization method
Assignee: Canon Inc
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Filing: 1994-11-02
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Granted: 2003-04-08
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Expires: 2014-11-02
Abstract
Abstract An image compressing apparatus including an input unit for inputting a plurality of spatial frequency component data of a block which is one of a plurality of blocks constituting an image, a discriminating unit for discriminating an image type of the block according to the spatial frequency component data input by the inputting unit with a predetermined value, a selecting unit for selecting one quantizing method from among a plurality of different quantizing methods, which respectively correspond to a plurality of image types, in accordance with the image type discriminated by the discriminating unit, and a quantizing unit for quantizing the spatial frequency component data of the block input by the inputting unit in accordance with the quantizing unit selected by the selecting unit.
Inventors
- 👤 Nobutaka Miyake
- 👤 Tadayoshi Nakayama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 11:34
CPC Classifications
G; G06; G06T; G06T9/00; G06T9/005
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
105 words
An image compressing apparatus comprising: input means for inputting all spatial frequency component data of a block which is one of a plurality of blocks constituting an image; discriminating means for discriminating an image type of the block according to the spatial frequency component data input by said input means; and quantizing means for quantizing all of the spatial frequency component data of the block input by said input means in accordance with the image type discriminated by said discriminating means, wherein said discriminating means discriminates the image type by comparing a single absolute value of the spatial frequency component data with a predetermined value.
Claim 2
Dependent Claim
105 words
An image compressing apparatus comprising: input means for inputting all spatial frequency component data of a block which is one of a plurality of blocks constituting an image; discriminating means for discriminating an image type of the block according to the spatial frequency component data input by said input means; and quantizing means for quantizing all of the spatial frequency component data of the block input by said input means in accordance with the image type discriminated by said discriminating means, wherein said discriminating means discriminates the image type by comparing a single absolute value of the spatial frequency component data with a predetermined value.
Claim 3
Dependent Claim
20 words
The apparatus according to claim 1 , wherein the image type is discriminated using an edge component of the block.
Claim 4
Dependent Claim
28 words
The apparatus according to claim 1 , wherein the spatial frequency component data is obtained from a multivalued image signal from a computer or from an image scanner.
Claim 5
Dependent Claim
25 words
The apparatus according to claim 1 , wherein said discriminating means discriminates based on an AC-power value within a high-frequency region in an orthogonal-transformed system.
Claim 6
Dependent Claim
23 words
The apparatus according to claim 4 , wherein the AC-power values in the high-frequency region are scanned from high-frequency components to low-frequency components.
Claim 7
Dependent Claim
46 words
The apparatus according to claim 1 , further comprising selecting means for selecting a quantizing parameter based on the ratio of the sum of powers in the low-frequency region of an orthogonal-transformed system to the sum of powers in the high-frequency region of the orthogonal-transformed system.
Claim 8
Dependent Claim
100 words
An image compressing method comprising the steps of: inputting all spatial frequency component data of a block which is one of a plurality of blocks which constitute an image; discriminating an image type of the block according to the spatial frequency component data input in said inputting step; and quantizing all of the spatial frequency component data of the block input in said inputting step in accordance with the image type discriminated by said discriminating step, wherein said discriminating step discriminates the image type by comparing a single absolute value of the spatial frequency component data with a predetermined value.
Claim 9
Dependent Claim
100 words
An image compressing method comprising the steps of: inputting all spatial frequency component data of a block which is one of a plurality of blocks which constitute an image; discriminating an image type of the block according to the spatial frequency component data input in said inputting step; and quantizing all of the spatial frequency component data of the block input in said inputting step in accordance with the image type discriminated by said discriminating step, wherein said discriminating step discriminates the image type by comparing a single absolute value of the spatial frequency component data with a predetermined value.
Claim 10
Dependent Claim
81 words
An image processing apparatus comprising: inputting means for inputting n×m pixels of block data, constituting one of a plurality of blocks constituting a given body of image data; transforming means for orthogonally transforming the block data into n×m spatial frequency component data; and output means for selecting an output order from a first order and a second order, the second order being the reverse of the first order, and outputting the n×m spatial frequency component data in the selected output order.
Claim 11
Dependent Claim
81 words
An image processing apparatus comprising: inputting means for inputting n×m pixels of block data, constituting one of a plurality of blocks constituting a given body of image data; transforming means for orthogonally transforming the block data into n×m spatial frequency component data; and output means for selecting an output order from a first order and a second order, the second order being the reverse of the first order, and outputting the n×m spatial frequency component data in the selected output order.
Claim 12
Dependent Claim
11 words
An image processing apparatus according to claim 8 , wherein n=m=8.
Claim 13
Dependent Claim
48 words
An image processing apparatus according to claim 8 , wherein spatial frequency component data are output from high frequency component to low frequency component in the first order, and wherein spatial frequency component data are output from low frequency component to high frequency component in the second order.
Claim 14
Dependent Claim
52 words
An image data processing apparatus according to claim 8 , further comprising discriminating means for discriminating an image type of the block data input by said inputting means, wherein an outputting order of spatial frequency data in said output means is determined based on the image type discriminated by said discriminating means.
Claim 15
Dependent Claim
45 words
An image processing apparatus according to claim 8 , wherein said output means comprises a plurality of address generators which generate a reading address of storing means for storing the n×m spatial frequency component data, each said address generator corresponding to a respective predetermined order.
Claim 16
Dependent Claim
33 words
An image processing apparatus according to claim 8 , wherein said output means changes an order of outputting spatial frequency component data while said output means is outputting the spatial frequency component data.
Claim 17
Dependent Claim
139 words
An image processing apparatus comprising: inputting means for inputting n×m pixels constituting a block which is one of a plurality of blocks constituting a given body of image data; transforming means for orthogonally transforming the block data into n×m spatial frequency component data; decision means for deciding a quantizing method from among a plurality of quantizing methods, which respectively correspond to a plurality of image types, based on an image type discriminated in accordance with the n×m spatial frequency component data obtained by said transforming means; and quantizing means for quantizing all of the n×m spatial frequency component data obtained by said transforming means using the quantizing method decided by said decision means, wherein, in said decision means, the image type is discriminated by comparing a single absolute value of the spatial frequency component data with a predetermined value.
Claim 18
Dependent Claim
139 words
An image processing apparatus comprising: inputting means for inputting n×m pixels constituting a block which is one of a plurality of blocks constituting a given body of image data; transforming means for orthogonally transforming the block data into n×m spatial frequency component data; decision means for deciding a quantizing method from among a plurality of quantizing methods, which respectively correspond to a plurality of image types, based on an image type discriminated in accordance with the n×m spatial frequency component data obtained by said transforming means; and quantizing means for quantizing all of the n×m spatial frequency component data obtained by said transforming means using the quantizing method decided by said decision means, wherein, in said decision means, the image type is discriminated by comparing a single absolute value of the spatial frequency component data with a predetermined value.
Claim 19
Dependent Claim
113 words
An image processing apparatus, comprising: transforming means for orthogonally transforming image data into spatial frequency component data; detecting means for detecting a characteristic of the image data based on the spatial frequency component data; a plurality of table means for respectively storing quantizing parameters; and quantization means for quantizing all of the spatial frequency component data by using quantizing parameters stored in one of said plurality of table means, which table means is selected according to the characteristic of the data detected by said detecting means, wherein said detecting means detects the characteristic of the image data by comparing a single absolute value of the spatial frequency component data with a predetermined value.
Claim 20
Dependent Claim
113 words
An image processing apparatus, comprising: transforming means for orthogonally transforming image data into spatial frequency component data; detecting means for detecting a characteristic of the image data based on the spatial frequency component data; a plurality of table means for respectively storing quantizing parameters; and quantization means for quantizing all of the spatial frequency component data by using quantizing parameters stored in one of said plurality of table means, which table means is selected according to the characteristic of the data detected by said detecting means, wherein said detecting means detects the characteristic of the image data by comparing a single absolute value of the spatial frequency component data with a predetermined value.
Claim 21
Dependent Claim
36 words
The apparatus according to claim 1 , wherein said discriminating means comprises means for discriminating the image type of the block by comparing each of the plurality of spatial frequency component data with a predetermined value.
Claim 22
Dependent Claim
37 words
The method according to claim 7 , wherein said discriminating step comprises a step of discriminating the image type of the block by comparing each of the plurality of spatial frequency component data with a predetermined value.
Claim 23
Dependent Claim
73 words
An image processing method comprising the steps of: inputting n×m pixels of block data, constituting one of a plurality of blocks constituting a given body of image data; orthogonally transforming the block data into n×m spatial frequency component data; selecting an output order from a first order and a second order, the second order being the reverse of the first order; and outputting the n×m spatial frequency component data the selected output order.
Claim 24
Dependent Claim
73 words
An image processing method comprising the steps of: inputting n×m pixels of block data, constituting one of a plurality of blocks constituting a given body of image data; orthogonally transforming the block data into n×m spatial frequency component data; selecting an output order from a first order and a second order, the second order being the reverse of the first order; and outputting the n×m spatial frequency component data the selected output order.
Claim 25
Dependent Claim
130 words
An image processing method comprising the steps of: inputting n×m pixels constituting a block which is one of a plurality of blocks constituting a given body of image data; orthogonally transforming the block data into n×m spatial frequency component data; deciding a quantizing method from among a plurality of quantizing methods, which respectively correspond to a plurality of image types, based on an image type discriminated in accordance with the n×m spatial frequency component data obtained by said transforming step; and quantizing all of the n×m spatial frequency component data obtained by said transforming step using the quantizing method decided by said deciding step, wherein, in said deciding step, the image type is discriminated by comparing a single absolute value of the spatial frequency component data with a predetermined value.
Claim 26
Dependent Claim
130 words
An image processing method comprising the steps of: inputting n×m pixels constituting a block which is one of a plurality of blocks constituting a given body of image data; orthogonally transforming the block data into n×m spatial frequency component data; deciding a quantizing method from among a plurality of quantizing methods, which respectively correspond to a plurality of image types, based on an image type discriminated in accordance with the n×m spatial frequency component data obtained by said transforming step; and quantizing all of the n×m spatial frequency component data obtained by said transforming step using the quantizing method decided by said deciding step, wherein, in said deciding step, the image type is discriminated by comparing a single absolute value of the spatial frequency component data with a predetermined value.
Claim 27
Dependent Claim
115 words
An image processing method for processing image data using a plurality of table means which respectively store quantizing parameters, said method comprising the steps of: orthogonally transforming image data into spatial frequency component data; detecting a characteristic of the image data based on the spatial frequency component data; and quantizing all of the spatial frequency component data by using quantizing parameters stored in one of said plurality of table means, which table means is selected according to the characteristic of the image data detected by said detecting step, wherein said detecting step detects the characteristic of the image data by comparing a single absolute value of the spatial frequency component data with a predetermined value.
Claim 28
Dependent Claim
115 words
An image processing method for processing image data using a plurality of table means which respectively store quantizing parameters, said method comprising the steps of: orthogonally transforming image data into spatial frequency component data; detecting a characteristic of the image data based on the spatial frequency component data; and quantizing all of the spatial frequency component data by using quantizing parameters stored in one of said plurality of table means, which table means is selected according to the characteristic of the image data detected by said detecting step, wherein said detecting step detects the characteristic of the image data by comparing a single absolute value of the spatial frequency component data with a predetermined value.
Claim 29
Dependent Claim
11 words
An image processing apparatus according to claim 14 , wherein n=m=8.
Claim 30
Dependent Claim
17 words
An image processing apparatus according to claim 14 , wherein said transforming means performs DCT coding processing.
Claim 31
Dependent Claim
44 words
An image processing apparatus according to claim 14 , wherein said quantizing means obtains AC component data and DC component data by quantizing all of the n×m spatial frequency component data, and outputs the AC component and the DC component through different terminals respectively.
Claim 32
Dependent Claim
45 words
An image processing apparatus according to claim 14 , wherein said transforming means performs zigzag scanning to convert the n×m spatial frequency component data into one dimensional data in which the frequency component data are arranged in a order corresponding to frequency of each component.
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