A Covert Communication Scheme for the DWT and Data Partitioning Based Image Multiple Description Coding System

In this paper, a covert communication scheme is proposed for a discrete wavelet transform (DWT) and packetization based image multiple description coding (MDC) system. Firstly, the secret information is embedded in the DWT domain of the carrier image by the parity modulation based method. And then, the DWT coefficient set is divided into 3 subsets, one is the horizontal subset, another is the vertical subset, the other is the diagonal subset. Each subset is compressed with the SPIHT algorithm, and one subset 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 DWT coefficients can be estimated by the ones which arrived at the receiver successfully. At the receiver side, the inverse procedures are performed to recover the carrier image and the secret information.