30 October 1975 DPCM Quantization Error Reduction For Image Coding
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A method for optimally reducing the error incurred during the quantization operation in DPCM image coding is presented. The method is optimum with respect to a mean-square error criterion and is applied a posteriori. The technique is based on knowledge of the multidimensional probability density function of the DPCM difference signal. The quantizer operates on this difference signal to achieve a data compression. The coarser the quantization, the greater the compression, but also the greater the degradation of the encoded image. To minimize the degradation, a reconstruction should utilize all of the knowledge that is available about the difference samples, such as their distribution, the quantization levels, and any correlation which remains after the differencing operation. An estimation equation which embodies this information is derived and solved. The solution is applied to images which have been either DPCM or deltamodulation encoded. The resultant images have lower mean-square error and exhibit an improvement in subjective quality.
© (1975) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
William K. Pratt, William K. Pratt, Michael N. Huhns, Michael N. Huhns, } "DPCM Quantization Error Reduction For Image Coding", Proc. SPIE 0066, Efficient Transmission of Pictorial Information, (30 October 1975); doi: 10.1117/12.965360; https://doi.org/10.1117/12.965360


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