On the application of turbo codes to the robust transmission of compressed images

Compressed images transmitted over noisy channels are extremely sensitive to bit errors. This necessitates the application of error control channel coding to the compressed representation before transmission. This paper presents an image transmission system which takes advantage of the superior performance of turbo codes, an important new class of parallel concatenated codes. Several aspects of the application of turbo codes to image transmission are studied, including comparison to a previous image transmission system using convolutional codes. Experimental results for several channel signal-to-noise ratios show that, in the same SNR range, turbo codes achieve much better performance with less decoding complexity than convolutional codes and that similar performance can be achieved at much lower channel SNRs. Studies also show that the use of feedback from an outer Reed-Solomon code to aid turbo decoding results in further improvement.