INFLUENCE OF A PERTURBATION IN A DOUBLE PHASE-ENCODING SYSTEM

We consider the recently proposed double phase-encoding system [Opt. L ett. 20, 767 (1995)]. We study the robustness of the decoding process, that is, the way in which a perturbation of the coded image modifies the decoded image. We demonstrate that the amplitude signal-to-noise r atio (SNR) in the decoded image is strictly (and not only statisticall y) equal to the SNR in the coded image for different kinds of coded-im age perturbations. In optical implementations the intensity of the dec oded image is measured at the output of the decoding system. We show t hat there exists a simple relation between the intensity SNR of the de coded image and the amplitude SNR of the coded image and that this rel ation is quasi-independent of the nature of the coded-image perturbati on. The results presented could provide a simple and efficient way of determining the precision level of the components of the optical decod ing system necessary to reach a predefined quality level of the decode d image. (C) 1998 Optical Society of America.