Walsh-Hadamard Transform/Differential Pulse Code Modulation (WHT/DPCM) Processing Of Intraframe Color Video
E. S. Kim, K.R. Rao · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 1979
Hybrid processing of NTSC color images for achieving bandwidth compression is simulated. The processing involves combination of transform and predictive coding of intraframe video. Walsh-Hadamard transform (WHT) along each row followed by differential pulse code modulation (DPCM) along each column is implemented in (16 x 16) and (32 x 32) blocks. Also 2d-WHT of (4 x 4) blocks together with prediction of adjacent blocks is investigated. Based on the histogram of the difference signal, quantizers are optimized for minimum mean square error between the original and processed images. Variable bit allocation reflecting the variance of the error signal is adopted for maintaining a specified bit rate. The processing schemes are evaluated in terms of both subjective and objective criteria.