Multiobject detection using the binary joint transform correlator with different types of thresholding methods

Abstract

The correlation performance of the binary joint transform correlator for multiobject detection is studied mathematically and experimentally using three types of thresholding methods. These thresholding methods include the spatial frequency dependent threshold function, the median thresholding, and the subset median thresholding. We provide a new expression for the image separation requirement in the input plane of the linear joint transform correlator for multiobject detection. Also, we introduce a new analytical approach for obtaining the threshold function in the binary joint transform correlator. The median thresholding method for multiobject detection by the binary joint transform correlator (JTC) is also analyzed. A hybrid optoelectronic setup is used for experiments. Two different implementations of the threshold function are employed in the experimental system. Experimental results of the binary JTC using different thresholding methods are determined and compared in terms of correlation peak-to-noise ratio, peak-to-sidelobe ratio, and space-bandwidth product. The results indicate that the binary JTC performs well for multiobject detection. Furthermore, using the threshold function in the binary JTC eliminates the first-order correlations between different input targets and the even-order harmonic terms in the output plane.