A Covert Communication Scheme for a SPIHT Based Image Multiple Description Coding System

In this paper, a covert communication scheme is proposed for a set partitioning in hierarchical trees (SPIHT) based image multiple description coding (MDC) system. Firstly, the carrier image is subsampled into four subimages. The secret information is embedded among the subimages with a discrete wavelet transform (DWT) and subsampling based method. The information embedding method is also proposed by us, which can resist not only the permutation attack but also some common image processing attacks. After the information having been embedded, the subimages are compressed by the SPIHT algorithm, and one subimage corresponds to one SPIHT stream. Then the SPIHT streams are packed and transmitted through the packet based channels individually. If there are packets lost, the lost packets can be substituted by the packets which reside in the other SPIHT streams. At the receiver side, the inverse procedures are performed to recover the carrier image and the secrete information.