The optical joint transform correlation based on liquid crystal spatial light modulator is a fast and parallel processing technique with high efficiency, which electronic correlation processing techniques can not match with. Similar to the correlation techniques in electronics, the sampling in optical joint transform correlation is of great importance for correlation algorithm. This paper discusses the space bandwidth problem in joint transform correlation identification experiment realized by electronic-addressing liquid crystal spatial light modulator (ELC-SLM) and CCD, and analyses the relation between focal length of Fourier lens and the resolution of lockport community television (LCTV) and charge-coupled device (CCD). Using double slit, the leaves of Dendrobium huoshanense(D.huoshanense) and so on as primary signal of correlation algorithm, it discusses the lineament and size of suitable joint transform correlation (JTC) using an object image and a reference image. In the experiment nonlinear exposure of power spectrum enhances the diffraction efficiency of correlation image. Using the joint transform correlation image recognition platform in experiment, there are leading in recognition to make quantization of recognition results. This research has certain significance to the joint correlation problem about the leaf image processing of D.huoshanense.
Adaptive Focal Length Imaging System using Liquid Crystal Spatial Light Modulator
