WYNER-ZIV CODING OF MULTISPECTRAL IMAGES FOR AIRBORNE PLATFORMS

This paper investigates the application of lossy distributed source coding to high resolution multispectral images. The choice of dis-tributed source coding is motivated by the need for very low encod-ing complexity on satellite or airborne platforms. The data consists of red, blue, green and infra-red channels and is compressed in an asymmetric Wyner-Ziv setting. One image channel is compressed using traditional JPEG and transmitted to the ground station where it is available as side information for Wyner-Ziv coding of the other channels. Encoding is accomplished by quantizing the image data, applying a Low-Density Parity Check code to the remaining three image channels, and transmitting the resulting syndromes. At the ground station, the image data is recovered from the syndromes by exploiting the correlation in the frequency spectrum of the band be-ing decoded and the JPEG-decoded side information band. Various methods are presented to best exploit this correlation, using real un-compressed images obtained by the – satellite. It is observed that the rate-distortion performance is vastly superior to that of JPEG com-pression of individual image channels and rivals that of JPEG2000 at much lower encoding complexity. Index Terms — multispectral, LDPC code, Wyner-Ziv coding 1