Comparative Survey of the DCT and the Wavelet Transforms for Image Compression

摘要

In the framework of the image compression by transform coding, we studied two transformation techniques, respectively, used in the JPEG and JPEG2000 standards: the discrete cosine transform (DCT) and the wavelets transform (WT). We also studied the influence of different coding techniques on the compression rate. We compare the performances of different wavelets. The set of the techniques that we implemented have been applied on different types of images. We verified the compromise that exists between the compression rate and the quality of the reconstructed image. We noted that when we apply the wavelet transform, we succeeded with best results of those found by the use of the DCT. We note also that the quality of reconstruction is better as we increase the order of the filter associated to the Daubechies wavelets.