رضا دیانت

In this paper, new vector quantization (VQ) based techniques for reducing the effect of channel noise in image transmission are introduced. In one of the proposed methods, i.e., component VQ (CVQ), by transmitting the components of code-vectors (and not their indices), we will be able to reduce the effect of channel noise. To decrease the output rate of CVQ, a modification of CVQ called sub-index VQ (SIVQ) is introduced. This method has errorcorrecting capability as well. Simulation results show that CVQ and SIVQ techniques are robust to channel errors and surpass the conventional method, in which the indices of the selected code-vectors are protected using a Reed–Solomon code. An error concealment technique called shifted block concealment (SBC) has been also introduced. The stationarity assumption of small blocks of images has been utilized to conceal losses in this method