We propose and demonstrate the application of coherence modulation of light in shadow casting correlation. This technique allows to carry out simultaneously several correlation products in order to increases the processing capacity of this correlator. The experimental results have been obtained with a broadband source, such as white-light source.
In this paper, we propose a new optical implementation for reference-phase-encoded joint transform correlation technique for efficient multiple target detection. The proposed method employs phase encoding for the reference image and nonlinear Fourier plane apodization for optimizing the detection performance. The reference phase-encoded joint transform Correlator (JTC) overcomes false target detection by eliminating the false correlation peaks while alleviating the effects of noise and other artifacts in just one-step thus ensuring higher processing speed. This technique yields only one peak per target instead of a pair of peaks produced by alternate JTCs. An all-optical implementation for the reference phase-encoded JTC technique is proposed and experimental results are presented.
The performance of target detection and tracking algorithms generally depends on the signature, clutter, and noise that are usually present in the input scene. To evaluate the effectiveness of a given algorithm, it is necessary to develop performance metrics based on the input plane as well as output plane information. We develop two performance metrics for assessing the effects of input plane data on the performance of detection and tracking algorithms by identifying three regions of operation—excellent, average, and risky intervals. To evaluate the performance of a given algorithm based on the output plane information, we utilize several metrics that use primarily correlation peak intensity and clutter information. Since the fringe-adjusted joint transform correlation (JTC) was found to yield better correlation output compared to alternate JTC algorithms, we investigate the performance of two fringe-adjusted JTC (FJTC)-based detection and tracking algorithms using several metrics involving the correlation peak sharpness, signal-to-noise ratio, and distortion invariance. The aforementioned input and output plane metrics are used to evaluate the results for both single/multiple target detection and tracking algorithms using real life forward-looking infrared (FLIR) video sequences.
In this paper, we proposed a new architecture, called nonzero-order fringe-adjusted joint transform correlator (FJTC) using a binary random phase mask, for real time pattern recognition applications. The binary random phase mask encodes the reference image by two equal probability phases before it is introduced in the joint input image. The joint power spectrum is then multiplied by the same phase mask to remove the zero-order term and false alarms that may be generated in the correlation plane due to the presence of multiple identical target or non-target objects in the input scene. The criteria used for measuring the performance of nonzero-order fringe-adjusted JTC include correlation peak intensity, peak-to-correlation energy, and peak-to-sidelobe ratio. Detailed analysis for the proposed nonzero-order FJTC using binary random phase mask is presented. Simulation results verify the effectiveness of the proposed technique.
The fringe-adjusted joint transform correlator (JTC) technique has been found to yield substantially better correlation performance than alternate JTC techniques. Since the fringe-adjusted JTC (FJTC) is sensitive to scale and rotation variations, a synthetic discriminant function (SDF) based FJTC was proposed to realize scale and rotation invariant pattern recognition system via computer simulation. In this paper, optoelectronic implementation of the scale and rotation invariant pattern recognition using SDF based FJTC has been tested for both binary and gray level images. The experimental results obtained are in close agreement with the simulation results obtained earlier.
To achieve scale and rotation invariant pattern recognition, we implemented synthetic discriminant function (SDF) based reference image in a nonzero order Fringe-adjusted Joint Transform Correlator (FJTC) using binary random phase mask. The binary random phase mask encodes the SDF based reference image before it is introduced in the joint input image. The joint power spectrum is then multiplied by the phase mask to remove the zero-order term and false alarms that may be generated in the correlation plane due to the presence of multiple identical target or non-target objects in the input scene. Detailed analysis for the proposed SDF based nonzero order FJTC using binary random phase mask is presented. Simulation results verify the effectiveness of the proposed technique.
The pattern matching for fingerprints requires a large amount of data and computation time. Practical fingerprint
identification systems require minimal errors and ultrafast processing time to perform real time verification and
identification. By utilizing the two-dimensional processing capability, ultrafast processing speed and noninterfering
communication of optical processing techniques, fingerprint identification systems can be
implemented in real time. Among the various pattern matching systems, the joint transform correlator (JTC) has
been found to be inherently suitable for real time matching applications. Among the various JTCs, the fringeadjusted
JTC has been found to yield significantly better correlation output compared to alternate JTCs. In this
paper, we review the latest trends and advancements in fingerprint identification system based on the fringeadjusted
JTC. Since all pattern matching systems suffer from high sensitivity to distortions, the synthetic
discriminant function concept has been incorporated in fringe-adjusted JTC to ensure distortion-invariant
fingerprint identification. On the other hand a novel polarization-enhanced fingerprint verification system is
described where a polarized coherent light beam is used to record spatially dependent response of the scattering
medium of the fingerprint to provide detailed surface information, which is not accessible to mere intensity
measurement. It is shown that polarization-enhanced database improves the accuracy of the fingerprint
identification or verification system significantly.
Keywords: Fringe-adjust joint transform correlation, finger print identification, polarization, synthetic
discriminant function
We introduce novel optoelectronic target detection technique using polarization enhancement. Images correspond to elements of Stokes vector imagery are introduced as input scenes to the fringe-adjusted joint-transform correlator. Our results show excellent improvement in performance parameters. Both computer simulation and experimental results are presented in support of the proposed technique.
Several metrics for quantifying the performance of fringe-adjusted joint transform correlator (JTC) technique are investigated in this paper. The criteria used for measuring the performance of fringe-adjusted JTC include peak sharpness, signal-to-clutter measure, distortion invariance, signal-to-noise ratio and a new metric called peak-to-background correlation energy is proposed in this paper. These metrics are used to estimate the reliability of signal detection in the input scene with respect to clutter, noise and other associated distortions. Detailed analysis and simulation results for quantifying the performance of fringe-adjusted JTC are presented.
In this paper, we report for the first time the feasibility of coding by coherence modulation in 2D optical correlator using a spatially and temporally incoherent light source. This technique allows to carry out simultaneously several correlation products. The reported results have been obtained with a broadband source, such as a white-light source.
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