VOLUME HOLOGRAPHIC OPTICAL CORRELATOR FOR HIGH-SPEED PARALLEL PATTERN RECOGNITION

摘要

1 Introduction It is well known that the parallel-processing capabilities of an optical image-processing system offer the benefits of high processing speed and the capability of handling images having a large spacebandwidth product. The foundation of modem optical image processing is the holographic matched filter proposed by Vander Lugt in 1964[1]. A typical multifilter optical eorrelator uses an input spatial light modulator(SLM),a filter-plane SLM supported by a massive electronic memory,and an output detector array[2-3]. Correlations between input objects and stored images are obtained by updating the filter-plane SLM with filter data from its supporting electronic memory while synchronously collecting data from the output detector array. This constant accessing of data from the massive electronic memory creates a bottleneck which reduces the overall processing-speed significantly. This is caused by the serial nature of electronic memory accessing and can be eleminated by using volume hologranhic storage.