Image-signal decoding apparatus
First Claim
1. An image signal decoding apparatus for decoding moving-picture data compressed per block by orthogonal transform, quantization and variable-length coding for each block, said apparatus comprising:
- variable-length code decoding means for decoding the compressed moving-picture data, and for outputting the decoded moving-picture data, a moving vector per block, and information on block type;
distortion-eliminating means for eliminating a block distortion for moving-picture data decoded by said variable-length code decoding means, according to a distortion elimination characteristic of said distortion-eliminating means;
judging means for obtaining a signal band for each block from the decoded moving-picture data, and for changing the distortion elimination characteristic of said distortion-eliminating means for each block on the basis of at least one of the signal band, the moving vector for each block and the information on block type;
said judging means comprising;
threshold-comparing means for comparing the decoded moving-picture data from said variable-length code decoding means with a predetermined threshold value, and for outputting a comparison result of the comparison between the decoded moving-picture data and the threshold value;
maximum frequency-judging means for computing a maximum frequency in at least one of a horizontal and a vertical direction from the comparison result; and
filter-determining means for determining at least one of kernel sizes and coefficients of at least one of horizontal and vertical filters on the basis of at least one of the maximum frequency in the horizontal and/or vertical directions, the moving vector and the information on block type.
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Abstract
An image-signal decoding apparatus decodes moving-picture data compressed by orthogonal transform, quantization, and variable-length coding for each block. A variable-length code decoding circuit decodes the compressed moving-picture data and outputs the decoded moving-picture data, a moving vector for each block, and block-type information. A distortion eliminator circuit eliminates block distortions from the moving-picture data decoded by the variable-length code decoding circuit. A judging circuit obtains a signal band for each block from the decoded moving-picture data and, based on the band and at least one of the moving vector for each block and the block-type information, changes the distortion elimination characteristics of the distortion eliminator circuit.
117 Citations
5 Claims
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1. An image signal decoding apparatus for decoding moving-picture data compressed per block by orthogonal transform, quantization and variable-length coding for each block, said apparatus comprising:
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variable-length code decoding means for decoding the compressed moving-picture data, and for outputting the decoded moving-picture data, a moving vector per block, and information on block type; distortion-eliminating means for eliminating a block distortion for moving-picture data decoded by said variable-length code decoding means, according to a distortion elimination characteristic of said distortion-eliminating means; judging means for obtaining a signal band for each block from the decoded moving-picture data, and for changing the distortion elimination characteristic of said distortion-eliminating means for each block on the basis of at least one of the signal band, the moving vector for each block and the information on block type; said judging means comprising; threshold-comparing means for comparing the decoded moving-picture data from said variable-length code decoding means with a predetermined threshold value, and for outputting a comparison result of the comparison between the decoded moving-picture data and the threshold value; maximum frequency-judging means for computing a maximum frequency in at least one of a horizontal and a vertical direction from the comparison result; and filter-determining means for determining at least one of kernel sizes and coefficients of at least one of horizontal and vertical filters on the basis of at least one of the maximum frequency in the horizontal and/or vertical directions, the moving vector and the information on block type. - View Dependent Claims (2)
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3. An image signal decoding apparatus for decoding moving-picture data compressed per block by orthogonal transform, quantization and variable-length coding, said image signal decoding apparatus comprising:
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variable-length code decoding means for decoding the compressed moving-picture data, and for outputting the decoded moving-picture data, a moving vector for each block, and information on block type; inverse quantizating means for performing an inverse quantization for the moving-picture data decoded by said variable-length code decoding means; inverse orthogonal transforming means for performing orthogonal transform for the moving-picture data to which the inverse quantization has been performed by said inverse quantizating means; distortion-eliminating means for eliminating block distortions of the moving-picture data output from said inverse quantizating means, according to a distortion elimination characteristic of said distortion-eliminating means; judging means for obtaining a signal band for each block of the moving-picture data to which the inverse quantization has been performed, and for changing the distortion elimination characteristic of said distortion-eliminating means for each block on the basis of at least one of the signal band, the moving vector for each block output from said variable-length code decoding means and the information on block type; and motion compensation predicting means for outputting a motion compensation predictive signal for a subsequent frame of the moving-picture data on the basis of at least one of the moving-picture data when block distortions have been eliminated by said distortion eliminating means, the motion vector for each block output from said variable-length code decoding means and the information on block type. - View Dependent Claims (4)
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5. An image signal decoding apparatus for decoding moving-picture data compressed per block by orthogonal transform, quantization and variable-length coding, said image signal decoding apparatus comprising:
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variable-length code decoding means for decoding the compressed moving-picture data, and for outputting the decoded moving-picture data, a moving vector for each block, and information on block type; distortion-eliminating means for eliminating block distortions of the moving-picture data decoded by said variable-length code decoding means, according to a distortion elimination characteristic of said distortion-eliminating means; judging means for obtaining a signal band for each block from the decoded moving-picture data, and for changing the distortion elimination characteristic of said distortion-eliminating means on the basis of at least one of the signal band, the moving vector for each block and the information on block type; said distortion-eliminating means comprising; color-difference signal changing means for receiving luminance-signal pixel judgement information and a color difference signal of said decoded moving-picture data, for changing the color difference signal so as to eliminate mosquito noise thereof, and for outputting the changed color difference signal; a source of a signal indicating a DCT coefficient of a specific frequency; and judging means for comparing the changed color difference signal with the signal indicating the DCT coefficient of a specific frequency, said judging means outputting the changed color difference signal when the signals satisfy predetermined conditions, whereas said judging means returning the changed color difference signal to said color-difference signal changing means when the signals deviate from the predetermined conditions.
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Specification