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IJPAP Vol.46 [2008] >
IJPAP Vol.46(12) [December 2008] >
| Title: | Design parameters of hybrid correlator |
| Authors: | Beri, Vinod K
Nishchal, Naveen K
Gupta, Arun K
Rastogi, V K |
| Keywords: | Optical correlator
Spatial light modulator
Wavelet function
Log-polar transform
Chirp function |
| Issue Date: | Dec-2008 |
| Publisher: | CSIR |
| Abstract: | In this paper, the design issues of a hybrid correlator are discussed. The architecture of the hybrid correlator is similar to the conventional 4-f correlator, with a difference that the first Fourier transformation, filter synthesis and their multiplica-tion are done digitally using a digital signal-processing unit. The input to the correlator is the scene/target captured either through a CCD camera or thermal imager. Wavelet-modified maximum average correlation height filter is used for catering the need of in-plane rotation, out-of-plane rotation and scale invariant target recognition. The product function is displayed over a high-speed spatial light modulator, which when illuminated with a laser light results correlation outputs due to optical Fourier transformation. A chirp function is employed with the filters that helps to capture the desired autocorrelation peak discarding the dc and one of the undesired autocorrelation peaks. The space-bandwidth of the processor and focal length of the required lens are discussed. The requirement of zero padding of the product function is also discussed. Simulation and experimental results are presented. |
| Page(s): | 844-851 |
| ISSN: | 0019-5596 |
| Source: | IJPAP Vol.46(12) [December 2008]
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