Paper
1 October 1999 Adapting the input scene and the filter to the operating curves of the modulators in real-time correlators
Juan Campos, Maria Josefa Yzuel, I. Moreno, Esmail Ahouzi, Andres Marquez, Octavio Lopez-Coronado, Abdelaziz Attaleb
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Abstract
In this paper we present some results on the research line of real-time correlation applied to optical pattern recognition. We present a real time optical correlator that uses two twisted nematic liquid crystal spatial light modulators (SLM). This kind of SLM produces phase and amplitude coupled modulation. Phase modulation is useful for the implementation of phase only filters (POF), but the coupled amplitude modulation affects its performance. We present a model to evaluate the response of the phase-only filter (POF) implemented on a modulator with a restricted modulation and we show results on the optimal implementation of POF of this restricted coding domain. The phase modulation is also used for the implementation of the scene by means of a phase-encoding algorithm. The performance of the phase-only filter has been improved for several performances criteria by the design of binary amplitude masks. We present a technique for the implementation of these optimized binary amplitude phase-only filters using phase-mostly SLMs. Results obtained for the optimization of different criteria are presented. Finally, we present results on the application of these methods to color pattern recognition problems by a multichannel correlation.
© (1999) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Juan Campos, Maria Josefa Yzuel, I. Moreno, Esmail Ahouzi, Andres Marquez, Octavio Lopez-Coronado, and Abdelaziz Attaleb "Adapting the input scene and the filter to the operating curves of the modulators in real-time correlators", Proc. SPIE 3804, Algorithms, Devices, and Systems for Optical Information Processing III, (1 October 1999); https://doi.org/10.1117/12.363966
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KEYWORDS
Phase only filters

Spatial light modulators

Phase shift keying

Modulation

Optical correlators

Phase modulation

Binary data

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