Image coding method and apparatus using spatial predictive coding of chrominance and image decoding method and apparatus
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Abstract
A method and apparatus for coding a chrominance component of an intra-image using spatial predictive coding and a method and apparatus for decoding the coded chrominance component are provided. The coding apparatus includes a variation calculator, which calculates a vertical variation and a horizontal variation with respect to a current block to be predictively coded among blocks having a predetermined size, into which a chrominance component of an input image is divided, using pixel values in an upper reference block adjacent to the current block and pixel values in a side reference block adjacent to the current block; a hybrid predictor, which divides the current block into a predetermined number of regions according to the vertical and horizontal variations and generates a prediction value of each pixel in each region using a pixel value in the upper reference block or a pixel value in the side reference block; a differential value generator, which generates a differential value between the prediction value and a corresponding real pixel value in the current block and codes the differential value using a predetermined coding method.
17 Citations
54 Claims
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1-10. -10. (canceled)
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11. A coding method comprising:
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(a) dividing pixels of a chrominance component of an input image into blocks having a predetermined size;
(b) dividing a current block to be predictively coded into a predetermined number of regions according to a predetermined number of prediction methods and generating prediction values of each pixel in the current block according to the respective prediction methods using a pixel value in an upper reference block adjacent to the current block and a pixel value in a side reference block adjacent to the current block;
(c) generating differential values between the prediction values corresponding to the respective prediction methods and a corresponding real pixel value in the current block; and
(d) selecting a differential value requiring a least number of bits for coding among the differential values and coding the selected differential value and information on a prediction method corresponding to the selected differential value using a predetermined coding method. - View Dependent Claims (12, 13, 14, 15, 16, 31)
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17. A coding method comprising:
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(a) dividing pixels of a chrominance component of an input image into blocks having a predetermined size;
(b) selecting one among a direct current prediction method, a vertical prediction method, a horizontal prediction method, and a hybrid prediction method according to a user'"'"'s input;
(c) generating a prediction value of each pixel in a current block to be predictively coded, using at least one pixel value among pixel values in an upper reference block adjacent to the current block and in a side reference block adjacent to the current block, according to the selected prediction method;
(d) generating a differential value between the prediction value and a corresponding real pixel value in the current block; and
(e) coding the differential value and information on the selected prediction method using a predetermined coding method. - View Dependent Claims (18, 19, 20, 32)
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21-30. -30. (canceled)
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33-43. -43. (canceled)
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44. A coding apparatus comprising:
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a hybrid predictor, which divides a current block to be predictively coded among blocks having a predetermined size, into which a chrominance component of an input image is divided, into a predetermined number of regions according to a predetermined number of prediction methods and generates prediction values of each pixel in the current block according to the respective prediction methods using a pixel value in an upper reference block adjacent to the current block and a pixel value in a side reference block adjacent to the current block;
a differential value generator, which generates differential values between the prediction values corresponding to the respective prediction methods and a corresponding real pixel value in the current block;
a selector, which selects a differential value requiring a least number of bits for coding among the differential values; and
a coder, which codes the selected differential value and information on a prediction method corresponding to the selected differential value using a predetermined coding method. - View Dependent Claims (45, 46, 47, 48, 49)
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50. A coding apparatus comprising:
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a selector, which selects one among predetermined prediction methods comprising a direct current prediction method, a vertical prediction method, a horizontal prediction method, and a hybrid prediction method according to a user'"'"'s input;
a predictor, which generates a prediction value of each pixel in a current block to be predictively coded among blocks having a predetermined size, into which a chrominance component of an input image is divided, using at least one pixel value among pixel values in an upper reference block above the current block and in a side reference block on left of the current block, according to the selected prediction method;
a differential value generator, which generates a differential value between the prediction value and a corresponding real pixel value in the current block; and
a coder, which codes the differential value and information on the selected prediction method using a predetermined coding method. - View Dependent Claims (51, 52, 53)
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54-62. -62. (canceled)
Specification