Mehdi Rabizadeh - K.N.Toosi University of Technology,Tehran,Iran
Ali Farmani - University of Tabriz,Tabriz,Iran
Mahdi Sadeghi - Tarbiat Moallem University of Sabzevar,Sabzevar,Iran

For the past few years, a joint ISO/CCITT committee known as JPEG (Joint Photographic ExpertsGroup) has been working to establish the first international compression standard for continuous-tone still images both grayscale andcolor .JEPG S proposed standard aims to be generic to support a wide variety of applications for continuous-tone images.To meet the differing needs of manyapplications, the JPEG standard includes two basic compression methods, each with various modes of operation. A DCT- based method is specifid for lossy compression and a predivtive method for lossless compression .JPEG features a simple lossy technique known as the baseline method a DCTsubsetof the other DCT-based modes of operation. The Baseline method has been by far the mostwidely implemented JPEG method to date, and is sufficient in its own right for a large number ofapplications. This article provides an overview of the JPEG standard, and focuses in detail on theBaseline method.

Image compression, Discrete Cosine Transform, VLSI, Entropy Coding