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US 5,416,606 AGranted
Method and apparatus for encoding or decoding an image in accordance with image characteristics
AssigneeCanon Kabushiki Kaisha
InventorsAkihiro Katayama, Yasuhiko Yasuda, Shigeo Kato
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Abstract
The invention relates to an image processing apparatus having the function to encode or decode image data and discloses a technique in which an optimum encoding method is selected in accordance with the characteristics of an image and a high efficient encoding with little deterioration in image is executed.
Claims47
An image encoding apparatus comprising:
- a) input means for inputting multi-level data for each pixel of an image;
- b) discriminating means for discriminating whether the input image data represents an edge portion or not;
- c) first encoding means for encoding the image data discriminated to be the edge portion by said discriminating means as binary image data by using a first encoding method, which is suitable for encoding the binary image data;
- d) second encoding means for encoding the image data outside of the edge portion as multi-value image data for each pixel on which binarization is not performed by using a second encoding method different from the first encoding method, the second encoding method being suitable for encoding the multi-value image data;
- and
- e) output means for outputting the image data encoded by said first and second encoding means.
3 more elements
An image encoding method comprising:
- a) an input step of inputting multi-level image data for each pixel of an image;
- b) a discriminating step of discriminating whether the input image data represents an edge portion or not;
- c) a first encoding step of encoding the image data discriminated to be the edge portion in said discriminating step as binary image data by using a first encoding method, which is suitable for encoding the binary image data;
- d) a second encoding step of encoding the image data outside of the edge portion as multi-value image data for each pixel on which binarization is not performed by using a second encoding method different from the first encoding method, the second encoding method being suitable for encoding the multi-value image data;
- and
- e) an output step for outputting the image data which was encoded by said first and second encoding steps.
3 more elements
An image processing system comprising:
- a) input means for inputting multi-value data for each pixel of an image;
- b) discriminating means for discriminating whether the input image data represents an edge portion or not;
- c) first encoding means for encoding the image data discriminated to be the edge portion by said discriminating means as binary image data by using a first encoding method, which is suitable for encoding the binary image data;
- d) second encoding means for encoding the image data outside of the edge portion as multi-value image data for each pixel on which binarization is not performed by using a second encoding method different from the first encoding method, the second encoding method being suitable for encoding the multi-value image data;
- e) memory means for storing the image data which is encoded by said first and second encoding means;
- f) decoding means for decoding the image data stored in said memory means;
- and
- g) output means for outputting the image data which was decoded by said decoding means.
5 more elements
An image encoding apparatus comprising:
- a) input means for inputting multi-value image data for each pixel of an image;
- b) discriminating means for discriminating whether the input image data represents an edge portion or not;
- c) first encoding means for encoding the image data discriminated to be the edge portion by said discriminating means as binary image data by using a first encoding method, which is suitable for encoding the binary image data;
- d) decoding means for decoding a code representing the encoded edge portion encoded by said first encoding means;
- e) eliminating means for eliminating the image data decoded by said decoding means from the input image data and generating difference data;
- f) second encoding means for encoding the difference data generated by said eliminating means as multi-value image data for each pixel on which binarization is not performed by using a second encoding method different from the first encoding method, the second encoding method being suitable for encoding the multi-value image data;
- and
- g) output means for outputting the image data encoded by said first and second encoding means.
5 more elements
A color image encoding apparatus comprising:
- a) input means for inputting image data composed of a plurality of color component data for each pixel of an image;
- b) discriminating means for discriminating whether the input image data represents an edge portion or not for each color component;
- c) first encoding means for encoding the image data discriminated to be the edge portion by said discriminating means as binary image data by using a first encoding method for each color component, the first encoding method being suitable for encoding the binary image data;
- d) eliminating means for eliminating the image data discriminated to be the edge portion from the input image data and generating difference data for each color component;
- e) second encoding means for encoding the difference data generated by said eliminating means as multi-value image data for each pixel on which binarization is not performed by using a second encoding method different from the first encoding method for each color component, the second encoding method being suitable for encoding the multi-value image data;
- and
- f) output means for outputting the image data encoded by said first and second encoding means.
4 more elements
Dependencies are inferred from the claim text.