A survey of methods for iterative signal restoration

The restoration of a distorted signal, and the closely related problem of recovering a signal from partial information, are crucial problems in signal processing. Attention is presently given to iterative algorithms applicable to signal restoration. The examples given illustrate that by incorporating a priori knowledge of the desired signal, impressive results are obtainable in problems for which direct, noniterative restorations are difficult to obtain. It is noted that although the constrained iterative technique is promising in many applications, much work remains to be done on such aspects of the method as convergence rates, noise effects, and the effects of errors in the modeling of distortions, as well as on the application of constraints.