Analysis of Image Compression Technique using DCT

Author : Virender Poswal, Priyanka, Munish Kumar

Abstract

Image compression is the application of data compression on digital images. Digital images contain large amount of Digital information that need effective techniques for storing and transmitting large volume of data. Image compression techniques are used for reducing the amount of data required to represent a digital image. An Image can be compressed with use of Discrete Cosine Transformation (DCT), quantization encoding are the steps in the compression of the JPEG image format. The 2-D Discrete Cosine transform is used to convert the 8×8 blocks of image into elementary frequency components .The frequency components(DC and AC) are reduced to zero during the process of quantization which is a lossy process .The quantized frequency components are coded into variable length codewords using encoding process. Distortion between the original image and reconstructed image is measured with PSNR(peak signal to noise ratio) with different compression factors. The compression ratio and PSNR val ues are different for different images.. It is found that performance will not remain same for different images even though compression factor was same

Keywords: Compression Ratio, Compression, PSNR.