Emulsion thickness and space variance: combined effects in Vander Lugt optical correlators

Previous studies have shown-that the intensity of the correlation peaks in Vander Lugt optical correlators can change with the position of the object because of emulsion thickness effects. In this paper, it is shown that the intensity variations are caused by a combination of thickness effects and a position-dependent frequency cutoff due to space variance of the optical processor. Experiments showing the global effect, as well as experiments showing each effect acting alone, have been performed.