Experimental implementation of a Wiener filter in a hybrid digital–optical correlator

Abstract

We present the implementation of a clutter-tolerant filter in a hybrid correlator system. Wiener filters were mapped with a complex encoding technique onto a smectic A(*) liquid-crystal spatial light modulator (SLM). The technique overcomes the problem of representing high-dynamic-range data on SLM's that have limited modulation capabilities. It also provides a compact image recognition system that is robust enough for many real-world applications. Experimental results are presented.

Subband mutiresolution by multi-object phase-only joint transform correlator

“…However, realization of filter coefficients and pixel values are a problem for amplitude-only JTC due to consisted negative values. To alleviate this problem, the phaseonly JTC technique has been reported, recently, in which both the input and Fourier planes are phaseencoded [9][10][11]. The phase-only JTC yields similar results as the amplitude only JTC as shown in Fig.…”

“…However, it allows the encoding of bipolar data (including positive and negative values) in the input plane unlike the amplitude-only JTC. This feature is attractive for the applications of correlation operation in case of bipolar data, such as filtering applications [11,12].…”

Image feature extraction by dynamic neural filtering and phase-only joint transform correlation

“…To alleviate this problem, POJTC technique has been reported recently, in which both the input and Fourier planes are phase-encoded [11][12][13]. The POJTC yields similar results as the amplitude-only JTC.…”

Noisy optical detection of chaos-based watermarks

“…An input signal, s, is placed in the input plane and is illuminated, and optically Fourier transformed to S. This signal is then optically mixed with the filter F in the Fourier plane. The new signal is again optically Fourier transformed to produce the correlation signal between the input image and the filter 17 . 5 shows the optical configuration of a Matched Filtering technique.…”