Data compression apparatus for video signal and method of data compression for video signal
First Claim
1. A data compression apparatus for video data having:
- dividing means for dividing said video data into unit blocks, converting means for orthogonally converting said video data at each of unit blocks, quantizing means for quantizing said orthogonally converted video data, and coding means for run-length-coding said quantized video data, comprising;
(a) first detection means for detecting sums of absolute values of said video data in horizontal and vertical directions within given filter passbands, respectively;
(b) second detection means for detecting a difference between said sums of absolute values; and
(c) control means for controlling the amount of coded data produced by said run-length-coding in accordance with a difference between said sums of absolute values.
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Abstract
A data compression apparatus for video data having: a dividing circuit for dividing the video data into unit blocks, a converter for orthogonally converting the video data at each of unit blocks, a quantizer for quantizing the orthogonally converted video data, and a coder for run-length-coding the quantized video data, comprises: a first detector for detecting powers of the video data in the horizontal and vertical directions within given bandpasses respectively; a second detector for detecting a difference between the powers; and a controller for controlling the amount of coded data produced by the run-length-coding in accordance with a total of the powers and the difference. This apparatus controls the amount of coded data in accordance with power of input video data and difference between powers of video data of the horizontal and vertical directions. A method for compressing input video data is also disclosed.
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Citations
9 Claims
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1. A data compression apparatus for video data having:
- dividing means for dividing said video data into unit blocks, converting means for orthogonally converting said video data at each of unit blocks, quantizing means for quantizing said orthogonally converted video data, and coding means for run-length-coding said quantized video data, comprising;
(a) first detection means for detecting sums of absolute values of said video data in horizontal and vertical directions within given filter passbands, respectively; (b) second detection means for detecting a difference between said sums of absolute values; and (c) control means for controlling the amount of coded data produced by said run-length-coding in accordance with a difference between said sums of absolute values. - View Dependent Claims (2, 3, 4, 5)
- dividing means for dividing said video data into unit blocks, converting means for orthogonally converting said video data at each of unit blocks, quantizing means for quantizing said orthogonally converted video data, and coding means for run-length-coding said quantized video data, comprising;
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6. A data compression apparatus for video data having:
- dividing means for dividing said video data into unit blocks, converting means for orthogonally converting said video data at each of unit blocks, quantizing means for quantizing said orthogonally converted video data, and coding means for run-length-coding said quantized video data, comprising;
(a) filter processing means for filtering said video data in horizontal and vertical directions separately; (b) detection means for detecting sums of absolute values of said video data in the horizontal and vertical directions; (c) difference detection means for detecting a difference between said sums of absolute values of said video data filtered in the horizontal and the vertical directions; (d) amount-of-code converting means for, in accordance with said difference, converting a total of said sums of absolute values to an amount of data which is a predictive value indicative of an amount of run-length-coded data; (e) first target setting means for setting a first target value; (f) passband limiting value converting means for producing passband limiting values of the horizontal and vertical direction in accordance with difference between said first target value and said amount of run-length-coded data; (g) passband limitation value conversion means for producing passband limitation values of horizontal and vertical directions in accordance with a difference between said mount of run-length-coded data and said first target value; (h) second target setting means for setting a second target value of the amount of run-length-coded data of said video data; (i) step size converting means for producing a step size signal in accordance with said second target value, said amount of run-length-coded data, and said passband limitation values; (j) passband limitation control means for controlling passband limitation of said video data before processing by said orthogonally converting means in horizontal and vertical directions in accordance with said passband limitation values; and (k) quantizing means for quantizing said orthogonally converted video data, a quantizing step size of said quantizing means controlled in accordance with said step size signal.
- dividing means for dividing said video data into unit blocks, converting means for orthogonally converting said video data at each of unit blocks, quantizing means for quantizing said orthogonally converted video data, and coding means for run-length-coding said quantized video data, comprising;
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7. A method of data-compressing for video data having the steps of:
- dividing said video data into unit blocks, orthogonally converting said video data at each of unit blocks, quantizing said orthogonally converted video data, and run-length-coding said quantized video data, comprising the steps of;
(a) detecting sums of absolute values of said video data in horizontal and vertical directions within given filter passbands respectively; (b) detecting a difference between said sums of absolute values; and (c) controlling the amount of coded data produced by said run-length-coding in accordance with said sums of absolute values. - View Dependent Claims (8, 9)
- dividing said video data into unit blocks, orthogonally converting said video data at each of unit blocks, quantizing said orthogonally converted video data, and run-length-coding said quantized video data, comprising the steps of;
Specification