A study on progressive transmission of digitised still images

Abstract

In this project, a progressive image transmission scheme based upon the Discrete Cosine Transform is investigated, for application in interactive monochrome image retrieval over low bandwidth channels. The scheme not only provides progressive transmission, but also guarantees a degree of compression with a. very small amount of distortion in the final reconstructed image. The aim of this project is to observe the efficiency of such a system as regards the compression ratio achieved, the quality of the reconstructed images in terms of the Mean Square Error, and the effect of channel errors on the latter. The image to be transmitted first undergoes the Discrete Cosine Transform. Selected coefficients are then quantised and coded before transmission. Subsequently, coefficients are progressively transmitted and utilised in reconstructing the successive approximations. A number of test images have been used to obtain the required results. The Mean Square Error was computed for each image to enable suitable comparisons.