A Modified Image Coder using HVS Characteristics Mrs

Embedded Zero Tree (EZW) coding, introduced by J.M Shapiro, is a very effective and computationally simple technique for image compression. Here we offer a technique which uses EZW and some simple blocks thereby increasing the compression ratio four times with a little degradation in Peak Signal to Noise ratio (PSNR) The proposed technique can be implemented without any change in the existing image coders by adding a Down Sampling Filter (DSF) and a Contrast Sensitivity Function (CSF) mask at the transmitter and a Up Sampling Filter (USF) at the receiver end. Besides improving the compression ratio the new method is about three times faster than the existing coding techniques.