Improved Image Compression Technique Using IWT-DCT Transformation

Wireless Image Compression is embedding scheme for reducing size of image so that image can be store in less disk space and faster attachment possible in communication. Research issues in Image Compression are to increase efficiency in term of the image quality of decompressed image on higher compression ratio and robustness against visual attacks. Discrete Wavelet transform domain based Image Compression is lossy compression technique. The disadvantage of DWT based compression is fraction loss in embedding which increases mean square error and results decreasing PSNR. Quality of decompressed image is proportional to PSNR. The Proposed compression approach use integer wavelet transforms to overcome above fraction loss. The paper presents Hybrid Integer wavelet transform (IWT) and discrete cosine transform (DCT) based compression technique to obtain increased quality of decompressed image compared to DWT+ DCT based compression technique. The proposed combined DWT+ DCT based compression technique reduces the fractional loss compared to DWT based compression so the proposed technique provides better image quality of decompressed image on high compression ratio compared to DWT based and hybrid DWT DCT based image compression techniques.