J. Wang et B. Javidi, MULTIOBJECT DETECTION USING THE BINARY JOINT TRANSFORM CORRELATOR WITH DIFFERENT TYPES OF THRESHOLDING METHODS, Optical engineering, 33(6), 1994, pp. 1793-1805
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.