Optical Pattern Recognition Technique
AssigneeOld Dominion University Research Foundation
InventorsMohammed Nazrul Islam, K. Vijayan Asari, Mohammad A. Karim
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Abstract
Disclosed is a distortion invariant system, method and computer readable medium for detecting the presence of one or more predefined targets in an input image. The input image and a synthetic discriminant function (SDF) reference image are correlated in a shift phase-encoded fringe-adjusted joint transform correlation (SPFJTC) correlator yielding a correlation output. A peak-to-clutter ratio (PCR) is determined for the correlation output and compared to a threshold value. A predefined target is present in the input image when the PCR is greater than or equal to the threshold value.
Claims3
An optical pattern recognition system comprising:
- a processing device coupled with a database of synthetic discriminant function (SDF) reference images, the processor for controlling the modulation and transformation operations;
- a laser light source for providing a coherent monochromatic light for a base carrier signal;
- a collimating lens for receiving the coherent monochromatic light and producing a parallel beam;
- a spatial light modulator (SLM) that includes phase mask and a fringe-adjusted filter capabilities, the SLM for receiving a phase encoded reference image and an input image to form a joint image such that the coherent monochromatic light passing through the SLM is modulated by the joint image;
- a Fourier lens for receiving the coherent monochromatic light modulated by the joint image;
- a recording device for capturing the Fourier transformed coherent monochromatic light modulated by the joint image and recording the intensity of the spectral signal as the joint power spectrum (JPS);
- and
- switching circuitry for receiving the JPS signal and feeding it back into the SLM such that the Fourier lens will perform an inverse Fourier transformation and the recording device will record the magnitude yielding a final correlation signal.
Dependencies are inferred from the claim text.