Adaptive type compression method for compressing a color image by imparting predetermined variable-length codes to combinations of quantized values based upon quantized prediction error components
First Claim
1. An adaptive type compression method for compressing a color image comprising the steps of:
- (i) forming a plurality of blocks of picture elements, said picture elements each being represented by a plurality of color image components separated from a color image signal, each said block of picture elements comprising two adjacent picture elements,
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Abstract
An adaptive type compression method for a color image in which each sequence of picture elements obtained by combination of sum-difference transformation with DPCM is compressed by being multiplied by an adaptive zonal filter. The sum-difference transformation is used to simplify transformation of the image into a spatial frequency zone. The zone filter characteristic is adaptively selected according to a predetermined transmission bit rate (compression rate). Further, this zonal filter characteristic is set so as to correspond with luminance and color difference signals. According to this method, image information to be recorded can be arbitrarily selected and distortion of the image at compressing and reproducing can be eliminated.
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Citations
9 Claims
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1. An adaptive type compression method for compressing a color image comprising the steps of:
(i) forming a plurality of blocks of picture elements, said picture elements each being represented by a plurality of color image components separated from a color image signal, each said block of picture elements comprising two adjacent picture elements, - View Dependent Claims (7)
- 2. (ii) obtaining sum components and difference components for each block using said color image components representing the two picture elements of each block,
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3. (iii) transforming said sum components and said difference components of each two adjacent blocks into predication error components for each block,
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4. (iv) quantizing said prediction error components on the basis of a quantization characteristic selected from a plurality of predetermined quantization characteristics,
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5. (v) obtaining a plurality of combinations of quantized values based upon the quantized prediction error components for each block, and
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6. (vi) imparting a predetermined variable-length code to each combination of quantized values.
Specification