One method of transmitting wavelet based zerotree encoded images over noisy channels is to add channel coding without altering the source coder. A second method is to reorder the embedded zerotree bitstream into packets containing a small set of wavelet coefficient trees. We consider a hybrid mixture of these two approaches and demonstrate situations in which the hybrid image coder can outperform either of the two building block methods, namely on channels that can suffer packet losses as well as statistically varying bit errors.

We present a novel robust image compression algorithm in which the output of a wavelet zerotree-style coder is manipulated into fixed-length segments. The segments are independently decodable, and errors occurring in one segment do not propagate into any other. The method provides both excellent compression performance and graceful degradation under increasing packet losses. We extend the basic scheme to perform region-based compression, in which specified portions of the image are coded to higher quality with little or no side information required by the decoder.

We describe a combined wavelet zerotree coding and packetization method that provides excellent image compression and graceful degradation against packet erasure. For example, using 53-byte packets (48-byte payload), the algorithm compresses the 512/spl times/512 gray-scale Lena image to 0.2 b/pixel with a peak signal-to-noise ratio (PSNR) of 32.2 dB with no packet erasure, and 26.3 dB on average for 10% packets erased.