Image Compression Using Wavelet Methods

This paper aims to study and compare the compression efficiencies of wavelet-bitmap and wavelet-Huffman. Both methods use wavelet to deduct a portion of the information in the image that can endure losing it without a significant disturbance in the image itself. Both methods deal with thresholding of wavelet coefficients to produce as much as possible zero coefficients for the purpose of higher compression, then encode the non zero coefficients by using Huffman encoding and bitmap drawing of the coefficients distribution resulted from thresholding inside the analyzed image. The processing time is calculated using MATLAB. Results were taken to compare the efficiencies of the compression between the two methods. In this work we present a method based on wavelet transforms using Huffman encoding and bitmap encoding. Different combinations of parameters and transforms have been compared. The result shows that the time of compression in wavelet-bitmap method is less than the time of compression which is taken by wavelet-Huffman method. Also the compression ratio in the wavelet-Huffman is greater than the other method. The quality in both methods is relatively equal.