On protection of compressed image in fading channel using data hiding

Abstract

Transmission of block-coded images through error prone radio mobile channel often results in lost blocks. To this aim, this paper proposes a protection mechanism for discrete cosine transform based compressed image(s) through error concealment without affecting the compatibility of standard JPEG coding. The goal is achieved by embedding a low-resolution version (image-digest) of an image into itself during encoding using M-ary quantization index modulation. Halftoning technique is used to obtain the image digest from the host image. At the decoder, this embedded watermark is extracted first and is then used as a reference one to conceal the transmission losses in the received image. Mathematical analysis as well as simulation results show that the use of M-ary modulation offers significant performance improvement than traditional quantization index modulation based methods in large number of lost block (packet) scenario. Relative compensation for visual quality improvement is also tested in Rayleigh fading wireless channel and is compared with the few other existing methods.