A Lossless Image Compression using Modified Entropy Coding

Abstract

Due to size limitation and complexity of the hardware in transmission applications, multimedia systems and computer communications, compression techniques are much necessary. The reasons for multimedia systems to compress the data, large storage is required to save the compressed data, the storage devices are relatively slow which in real-time, has constrain to play multimedia data, and the network bandwidth, that has limitations to real-time data transmission. This paper presents an enhanced approach of run length coding. First the DCT applied, and the quantization done on the image to be compressed, then the modified run length coding technique has been used to compress the image losslessly. This scheme represents the occurrence of repeated zeros by RUN, and a non-zero coefficient by LEVEL. It removes the value of RUN, as for the sequence of non-zero coefficients it is zero for most of the time and for a zero present between non-zero coefficients is replaced by ‘0’ which results in larger compression than RUN, LEVEL (1, 0) pair is used.