Non-Transform Methods of Picture Compression Applied to Medical Images

摘要

A variant of differential pulse code modulation (DPCM), bounded differential and shift encoding, is tested on a set of medical images. The 512 × 512 8-bit pixel images were digitized from film plates. The pixel and pixel difference distributions of the digital images were analyzed along with the entropy of these images. One version of the bounded differential and shift encoding method was tested along with several variants using additional quantization. The tests included measurements of the amount of data compression and the error introduced by quantization. The results demonstrate compression in the range of 3 - 5 bits per pixel and mean square error in the range .003% to .6%. Comparison with several non-causal methods shows that the coding method tested offers less compression, but less error combined with simpler implementation.