Effect of Quality Factor on DCT Based JPEG Technique

A joint ISO/CCITT committee known as JPEG (Joint Photographic Experts Group) has been working to establish the first international compression standard for continuous tone still images, both grayscale and color. JPEG's proposed standard aims to be generic, to support a wide variety of applications for continuous tone images. In this paper, we analyze the impact of Quality Factor choices on the quality of the resulting images. In this paper we implement the DCT based JPEG technique using MATLAB Software in which we have shown the variation of Compression Ratio, Peak Signal to Noise Ratio, Encoding Time, Decoding Time by varying the Quality Factor. In order to further improve the quality of compressed JPEG images it means to increase the peak signal to noise ratio we have to decrease the quality factor. This paper gives the method to improve compression ratio and quality of compressed images by DCT based method of JPEG by varying the quality factor.