Rademacher transform possesses a superior quantization which is free from accumulation of quantizing errors. The quantization is applicable to the coding of a large image which saves a transform steps. Such a fast transform is desirable for the real time processing of a television pictures.

Rademacher transform image coding has been investigated for monochrome image coding. This paper presents a experimental extension of the technique to the coding of NTSC signals obtained from still pictures. A computer simulation shows that good coding performance has been obtained.

A design method of rate-distortion optimum scalar quantizer is developed, and performance of the optimum quantizer is compared with those of linear quantizers using mean square error and output entropy, for a simple class of probability density function (pdf.). The simple class means that pdf. is unimodal and symmetric about its mode value, and is differentiable in both sides of symmetry. The method proposed here is based on solving Kuhn-Tucker condition and is essentially the same as those reported before (by Berger or by Farvardin and Modestino), but is shown to be a more advantageous method. Moreover, it has the rules in what region the initial value must be given and how one stop of iteration is solved, and checkpoints for the existence and number of solutions, those have not been shown before except empirically. Without these rules, it seems to be very perplexed problem to check upon the solutions, and algorithm of calculation would be very complicated and time consuming, for even a pdf. of the simple class. Performance of the optimum quantizer is obtained for standard normal distribution and Laplacian distribution with unit variance. It is compared with two kinds of linear quantizers. One is ordinary linear quantizer and the other is equi-interthreshold quantizer with optimized reconstruction levels. Detailed comparisons seem to show that equi-interthreshold quantizer has the most recommendable performance, at least for the pdf's examined here.

High efficient coding of monochrome images using new implementation of Rademacher transform is described. A computer simulation has been performed to evaluate performance of the system. The system proposed here shows less sensitivity to type of pictures.