Information preserving transmission systems of continuous‐tone picture signals for picture data base

Abstract

In a picture data base the picture quality required depends on the actual application of the picture signal. Therefore efficient reversible coding systems are needed. On the other hand, users demand easy searching of the required pictures. Considering the above facts, two kinds of information preserving transmission systems‐System 1 and System 2‐are proposed for picture data base treating 8‐bit PCM picture signals. In these systems, first, reference picture signal for user's reference are transmitted. Next, a supplementary transmission is performed. In System 1 a degenerate differential signal between PCM picture signal and reference picture signal is encoded and transmitted. In System 2, PCM picture signal is reversibly encoded and transmitted directly. In this paper, four kinds of coding systems are considered as coding system for reference pictures. The best performance has been achieved by discrete cosine transform coding. In addition, this paper presents a method for determining the better system in performance of supplementary transmissions of the two systems on the basis of signal‐to‐noise ratio of the reference picture. Finally, the realization of a transmission system is shown which combines the advantages of both Systems 1 and 2 by choosing the better system on the basis of coding performance at each reference picture.