Embedded Multiple Description Scalar Quantizers and wavelet-based QuadTree coding for progressive image transmission over unreliable channels

In this paper, we present a new Multiple Description Coding (MDC) system that enables the progressive transmission of images over unreliable channels with variable bandwidth. The proposed system employs a new type of quantizers, called Embedded Multiple Description Scalar Quantizers (EMDSQ). The system relies on wavelet-based QuadTree (QT) coding of the significance maps to encode the quantizers´ output, and is referred to as Multiple Description-QT (MD-QT) coding. The EMDSQ enables the MD-QT coder to provide bit-streams that meet the desired features consisting of a high redundancy level, fine-grain rate adaptation and progressive transmission of each description. Experimental results show that the proposed MD-QT system based on EMDSQ yields better rate-distortion performance in comparison to MD-QT employing the embedded Multiple Description Uniform Scalar Quantizers (MDUSQ) previously proposed in the literature.