MULTIOBJECT DETECTION USING THE BINARY JOINT TRANSFORM CORRELATOR WITH DIFFERENT TYPES OF THRESHOLDING METHODS

The correlation performance of the binary joint transform correlator f or 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 ex pression for the image separation requirement in the input plane of th e linear joint transform correlator for multiobject detection. Also, w e introduce a new analytical approach for obtaining the threshold func tion in the binary joint transform correlator. The median thresholding method for multiobject detection by the binary joint transform correl ator (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 b inary JTC using different thresholding methods are determined and comp ared in terms of correlation peak-to-noise ratio, peak-to-sidelobe rat io, and space-bandwidth product. The results indicate that the binary JTC performs well for multiobject detection. Furthermore, using the th reshold function in the binary JTC eliminates the first-order correlat ions between different input targets and the even-order harmonic terms in the output plane.