Wavelet Based Image Compression using Daubechies Filters

Digitized images have replaced analog images as photographs or x-rays in many different fields. In their raw form, digital images require a tremendous memory capacity for storage and large amount of bandwidth for transmission. In the last two decades, many researchers have been devoted to develop new techniques for image compression. More recently, wavelets have become a cutting edge technology for compressing the images by extracting only the visible elements. In this paper a wavelet based image decomposition algorithm has been implemented. Also, a nonuniform threshold technique based on average intensity values of pixels in each sub band has been proposed to remove the insignificant wavelet coefficients in the transformed image. Experimental results are obtained to compare the Daub2, Daub3 and Daub4 compactly supported (Daubechies) orthogonal wavelets on various test images using two important performance parameters – compression ratio and PSNR.