VQ on projection domain of image

摘要

Vector quantization (VQ), which is the optimal image compression technique, reduces bit-rate using interpixel correlation in a block of an image. As the block size increases, the performance of VG improves, but serious problems exist on the computational complexity and the required memory. Also, a serious problem of VQ, which is intrinsic in block coding schemes, is blocking effects. It degrades the image quality severely. This paper presents an image compression scheme, Projection-VQ, based on VQ of projections instead of an image itself. The vector dimension of a projection is much smaller than that of the image. Therefore, we may easily process a large block in projection domain. In Projection-VQ, a block image is projected at several angles. If we transmit the projections which have edge information, we can reconstruct an image without destroying edge sharpness even with a few projections. Simulation results show that the performance of the suggested scheme is superior to the normal VQ scheme in the sense of PSNR. Also, substantial improvement in subjective image quality can be attained because the staircase noise, which is a kind of blocking effects, is not visible in the reconstructed image.