This paper describes about the quality or fidility of the decommpressed image. The original image include the random noise, and if we try to decompress the noise, the coding efficiency is not good. If we remove the noise from the original and add noise after decompression, we can improve the coding efficiency keeping the quality. As the higher resolution image include more noise, this cut and add methode is effective for higher resolution image. The relations between the resolution and coded information are shown in graphs and also with formulae.
MPEG2 is a generic coding standard for high quality video and audio. Supplying the standard for digital compression video/audio formats has a great significance for exchanging data in many multimedia applications. In addition, MPEG2 is employed in several HDTV and digital satellite broadcasting systems. Defining the digital format is going to bring new applications in a fusion area of the conventional broadcasting, communication and storage media. In this paper, the MPEG2 standardization work and its technical contents are described.
In lossless encoding, a JBIG(Joint Binary Image Group) encoding algorithm has been standardized internationally for an image data, based on adaptive bi-level arithmetic encoding. LHa, based on Lempel-Ziv encoding algorithm, has been widely used in PC environment, and has a great compression efficiency. In this paper, first of all, I will overview a current and future application of compression technology and algorithms of JBIG and Lempel-Ziv encoding and introduce its compression ratio. Next, we will make a brief report of performance enhancement by edge conversion, under research and development, as a pre-process of these algorithms.