Scale-invariant optical correlators using ferroelectric liquid-crystal spatial light modulators.

New experimental results for scale-invariant implementations of the binary phase-only matched filter and the nonlinear joint transform correlator using ferroelectric liquid-crystal spatial light modulators are presented. We provide a comparative study of both architectures for real-time road-sign recognition. Signal-to-peak-noise ratios in excess of 5 dB over a scale range of 1.0 to 2.0 are achieved under realistic conditions of clutter.

[1]  B. Javidi.  Nonlinear joint power spectrum based optical correlation. , 1989, Applied optics.

[2]  Uri Mahlab,et al.  Optical pattern recognition based on convex functions , 1991 .

[3]  B Javidi,et al.  Technique for reducing the redundant and self-correlation terms in joint transform correlators. , 1993, Applied optics.

[4]  D. O’brien,et al.  Dynamic asymmetric binary holograms using a ferroelectric liquid crystal spatial light modulator , 1994 .

[5]  Kristina M. Johnson,et al.  Joint Transform Correlation Using An Amorphous Silicon Ferroelectric Liquid Crystal Spatial Light Modulator , 1990, Optics & Photonics.

[6]  Demetri Psaltis,et al.  V Deformation Invariant, Space-Variant Optical Pattern Recognition , 1978 .

[7]  B. Fracasso,et al.  Joint transform correlator using nonlinear ferroelectric liquid-crystal spatial light modulator , 1991, Optics & Photonics.

[8]  Mondher Attia,et al.  Optical roadsign recognition to improve active safety features , 1993, Defense, Security, and Sensing.

[9]  Kristina M. Johnson,et al.  Joint transform correlator using an amorphous silicon ferroelectric liquid crystal spatial light modulator , 1990 .

[10]  D C O'Brien,et al.  Scale-invariant binary phase-only matched filter using a ferroelectric-liquid-crystal spatial light modulator. , 1994, Applied optics.

[11]  Don A. Gregory,et al.  Joint transform correlation using an optically addressed ferroelectric LC spatial light modulator. , 1990, Applied optics.

[12]  Bahram Javidi,et al.  Multiple Object Identification By Bipolar Joint Transform Correlation , 1988 .

[13]  D. Casasent,et al.  Minimum average correlation energy filters. , 1987, Applied optics.

[14]  Kristina M. Johnson,et al.  Ferroelectric Liquid Crystal Spatial Light Modulators , 1990, Optics & Photonics.

[15]  D A Jared,et al.  Optical correlator using very-large-scale integrated circuit/ferroelectric-liquid-crystal electrically addressed spatial light modulators. , 1993, Applied optics.