Coherence length gated optical imaging system

Abstract

An apparatus for providing an image of an object, a diffusive medium being ocated between the apparatus and the object, the apparatus including a coherent light source for projecting a beam of coherent light through the diffusive medium onto various light reflective parts of the object. The coherence length of the projected beam is preferably very short, and each reflective part of the object is located in one of one or more discrete viewing spaces, the depth of field of the apparatus being equal to the coherence length of the projected light. A photocathode or the like is provided for receiving light reflected back through the diffusive medium from the reflective parts, discrete incremental sections of the photo-cathode responding to received light by generating sets of light responsive signals. Each set corresponds to a different viewing space, and the light responsive signals of a given set represent an image of the light reflective parts of the object which are located in the viewing space to which the given set corresponds. Integrating apparatus is provided to combine the light responsive signals of the sets to provide an image of the object.