Variable Sampling Rate Coding System for Picture Data Using Direct Quantization

Abstract

An improved variable sampling rate coding system for picture data, aiming real-time efficient equalization of information-speed with less noise, is proposed.
In this coding system, the rapidly chainging part of signal corresponding to sharp edge in the picture is encoded by quantizing the amplitude difference between two Nyquist-rate samples, while the slowly chainging part of the signal is encoded by quantizing the time-interval where the signal remains in an adequate aperture width.
As an extension of this technique to the two dimensional problem, a dual-mode coding, i. e. the combination of intra and inter line mode, is discussed. With this technique, the smear-like noise often appering in the reproduced picture can be eliminated.
The computer simulation of this coding system using typical images shows that the average transmission rate of 2. 2-2. 8 bits/pel results in satisfactory reproduction. Subjective evaluation tests also confirm the above results.