High picture quality image compression technique for mobile communication

High picture quality image compression technique for mobile communication is presented. The exact location information of the important DWT coefficients is generally needed for reconstructing the image. In this work, however, such information is not needed because it can be obtained from the DWT-approximation. Through a one dimensional directional difference operator not only the exact location information of the DWT coefficients but also the rough estimate of the coefficient itself can be obtained from the DWT-approximation when Haar mother wavelet function is utilized. The direction of the difference operator are different each other according to the DWT-details (horizontal, vertical and diagonal detail). This paper shows highly efficient image compression can be achieved when such DWT-approximation information is utilized well.