An Approach for Color Image Compression of JPEG and PNG Images Using DCT and DWT

Now a days image compression has become is an indispensible part of digitized image storage and transmission. Compression of an image is necessary before storing and transmitting it due to its limitation of storage and bandwidth capacity. Wavelet transform decomposes complexion of images into its elementary forms. In this paper, a comparative study has been carried out on image compression using DCT (Discrete Cosine Transform) and DWT (Discrete Wavelet Transform). A comparison is outlined to emphasize the results of this compression system between DCT and DWT using JPEG (Joint Photographic Experts Group) and PNG (Portable Network Graphics) color images. We have done conversion of color images into gray scale and also compression of gray scale image is shown after conversion using DWT method. DWT algorithm performs much better than DCT algorithms in terms of Compression, Mean Square Error (MSE) and Peak Signal to Noise Ratio (PNSR).