The Indirect Rate-Distortion Function of a Binary i.i.d Source

Abstract

The indirect source-coding problem in which a Bernoulli process is compressed in a lossy manner from its noisy observations is considered. These noisy observations are obtained by passing the source sequence through a binary symmetric channel so that the channel crossover probability controls the amount of information available about the source realization at the encoder. We use classic results in rate-distortion theory to compute the rate-distortion function for this model as a solution of an exponential equation. In addition, we derive an upper bound on the rate distortion which has a simple closed-form expression and investigate the coding scheme that attains it. These expressions capture precisely the expected behavior of the rate-distortion function: the noisier the source observations, the smaller the reduction in distortion obtained from increasing the compression rate.