A Comparative Study of DCT, DWT & Hybrid (DCT-DWT) Transform

Abstract

Image compression is process to remove the redundant information from the image so that only essential information can be stored to reduce the storage size, transmission bandwidth and transmission time. The essential information is extracted by various transforms techniques such that it can be reconstructed without losing quality and information of the image. In this paper comparative analysis of image compression is done by three transform method, which are Discrete Cosine Transform (DCT),Discrete Wavelet Transform(DWT) & Hybrid (DCT+DWT) Transform. Matlab programs were written for each of the above method and concluded based on the results obtained that hybrid DWT-DCT algorithm performs much better than the standalone JPEG-based DCT, DWT algorithms in terms of peak signal to noise ratio (PSNR), as well as visual perception at higher compression ratio.