Multiple description image coding for noisy channels by pairing transform coefficients
Multiple description coding (MDC) is a way of trading off coding gain with robustness to channel errors. This paper presents a new method for MDC using the framework of transform coding. Instead of using the Karhunen-Loeve transform (KLT) that decorrelates all the coefficients, we choose the transform bases so that the coefficients are correlated pair-wise. This is accomplished by rotating every two basis vectors in the KLT. Each pair of correlated coefficients are then split between two descriptions. Only 45/spl deg/ rotation is considered which leads to two balanced streams. In the actual implementation, the DCT is employed in place of the KLT and the rotation of transform bases is accomplished by rotating the DCT coefficients. Experimental results show that this method can lead to satisfactory image reconstruction from any one description with a relatively small (20% for "lena") overhead over a standard JPEG coder.