Integrated zigzag Vander Lugt correlators incorporating an optimal trade-off synthetic discriminant filter for invariant pattern recognition

Optical correlators (OCs) have a wide range of applications in the field of pattern recognition. We present a type of integrated zigzag Vander Lugt correlator (IZVLC). The IZVLC incorporates two Fourier transform lenses and one spatial light modulator (SLM) as a programmable filter, which can effectively miniaturize the volume of OCs and hence achieve better optical pattern recognition. In order to precisely recognize distortion targets, an optimal trade-off synthetic discriminant filter (OTSDF) is programmed on the SLM of the IZVLC. Both the simulative and experimental results have shown that the IZVLC can effectively identify distortion targets within a rotation angle of ±π/3 and a scaling range of 0.6-1.6.