Apparatus for hierarchical encoding of digital image signals with improved encoding efficiency

摘要

An input digital video signal is encoded to produce at least first and second hierarchical data signals which respectively represent a first video signal and a lower resolution video signal. Each pixel data signal of the second hierarchical data signal is calculated as an average of N pixel data signals of the input digital video signal. The second hierarchical data signal is output together with first hierarchical pixel data signals representing only N-1 of the N pixel data signals of the input digital video signal. The first hierarchical pixel data signals may be differential signals produced by subtracting each of the N-1 pixel data signals from the average value of the N pixel data signals. During decoding the Nth pixel data signal is reconstructed from the N-1 pixel data signals and the average value provided as the corresponding second hierarchical pixel signal.