Low bit-rate vector quantization with progressive transmission

This paper proposes a VQ-based coding scheme to perform the fast progressive transmission of images. The basic idea is to exploit the inter-block correlation by jointly encoding the indexes generated by the vector quantizer. The use of ordered codebooks for VQ guarantees that the indexes are highly correlated and therefore that the compression will be successful. In order to preserve the progressive transmission property the compression is carried out at the bit-plane level, by means of a classified-predictive encoding scheme. Numerical experiments on well-known test images show a rate reduction of about 30% in case of full-transmission, and of over 60% in case of partial-transmission, the latter being by far the most common situation in the applications.