Optical EngineeringIncoherent optical correlators and phase encoding of identification codes for access control or authentication
|Format||Member Price||Non-Member Price|
We show how phase-only filters can be used in incoherent optical correlators for security applications such as access control, identification, or authentication. As a specific example, a biometric signature, a fingerprint, is encoded in a phase-only representation. The phase encoding is accomplished with the method of generalized projections onto constraint sets implemented by an iterated Fourier transform algorithm. The operation of an incoherent optical security system using both a phase-only filter generated with the generalized projections algorithm and a phase-only matched filter is simulated. The results demonstrate that the selected access pattern was accepted while a false pattern was rejected by the security system and that better recognition and discrimination performance was attained with the phase-only filter produced by the generalized projections algorithm.