Real-Time Large Memory, Optical Pattern Recognition.

A large memory optical recognition system has been developed and tested. The memory consists of an array of stored holographic Fourier transform matched filters in a Vander Lugt type correlator. The filters are stored (on high resolution Kodak plates) and addressed using a novel holographic multi-focus lens. This element acts as a diffraction grating, splitting the input beam into 25 elements and as a lens, producing the Fourier transform of each of the 25 elements. the filters are created and addressed using a HeNe laser and a Hughes liquid crystal light valve (LCLV) to produce a coherent image from a television monitor. The LCLV also allows the filters to be addressed in "real-time" thereby making the use of a transparency as an input scene unnecessary. This provides for real -time recognition. Thus far, more than seventy matched filters have been stored on a single holographic plate and addressed in parallel and in real time with good correlations resulting. This research and the results obtained should contribute to allowing serious consideration to be given to the use of optical recognition systems for a wide variety of civilian and military applications.