LARGE CAPACITY TWO-DIMENSIONAL SCANNING OPTICAL CORRELATOR AND ITS APPLICATION

Optical correlation detection utilizing matched spatial filters (MSF) has been successfully applied to pattern recognition, radar signal detection, and speech recognition. However, the system throughput of the available techniques is generally limited by the inefficient use of the system capacity. Several novel approaches to building a large capacity, versatile, and high performance optical correlator are presented. The large system capacity is first achieved by a wavelength-angle multiplexing scheme such that up to 1000 MSFs can be recorded on a single photographic plate. Multiple signal detection capability using this technique has been proved very successfully. A white light achromatic pattern recognition scheme has demonstrated that the wavelength-angle multiplexing correlator can be operated as a parallel processing instrument. A radial-angle multiplexing scheme even further improved the system capacity such that up to 1300 MSFs can be constructed on a single photographic plate. These large capacity optical correlators can be operated under computer/electronics control for high accuracy and flexibility. The hybrid system possesses large space-bandwidth product and high speed which are the inherent advantages of optical processing.;The temporal and spatial coherence requirements for optical correlation detection have been evaluated on a useful pattern and error estimation of the large capacity correlator system is also performed. The optical pattern recognition successfully applied to small particle sizing is presented, and other applications of these optical correlators include: radar signal processing and speech recognition. In addition, these techniques may be incorporated into a robotic vision system for image recognition.