Combined spatial and frequency domain coding algorithm

摘要

Usage of image has been increasing and used in many applications. Image compression plays vital role in saving storage space and saving time while sending images over network. One important point of delivering digital image is time. In this paper we concentrated on the speed of image sending with reasonable quality. The aim of this paper is to reduce image size with reasonable quality. By getting advantage from image transformation in both scope spatial domain and frequency domain. In the case of spatial domain we take the average value (AV) of each four neighbor pixels and put this average value for one of these four neighbor pixels and ignore other three pixels which give us 1:4 compression ratio. In the case of frequency domain, we apply the simplest wavelet transform, the so called Haar wavelet transform (HWT) to reduce the image size with reasonable quality. In order to obtain better performance and overcome the disadvantages of the spatial domain method, we proposed a combined spatial domain and frequency domain (AV-HWT) approach in this paper. Matlab numerical and visualization software was used to perform all of the calculations and generate and display all of the pictures in the simulation. Experimental results prove the effectiveness of proposed algorithm.