Analysis of Post-processing Techniques for Compressed Images

Image compression is very problematic issue for several applications in the area of visual communication. The primary objective of image compression is to reduce the transmission and storage cost and also to maintain the perceptual quality of an image without any loss of information. Block-based discrete cosine transform (BDCT) is mostly used to compress images and videos due to its high energy compaction feature. When bit rate becomes low, compression techniques yield visually annoying blocking artefacts which highly degrade the quality of an image. To maintain the perceptual quality and achieves high bit rates, post-processing methods provide an excellent solution. In this paper, we provide an analysis and review of currently advancement in post-processing methods. Post-processing methods are classified into two categories: spatial domain transform and frequency domain transform. Finally, future research directions and current bottlenecks in this area are addressed.