Multichannel single-output color pattern recognition by use of a joint-transform correlator

Abstract

A novel method for performing color image recognition by the use of the coherent joint-transform correlator is introduced. The input plane of the proposed method is a spatial rearrangement of the separation into color channels of both the color input scene and the color target. This input plane is gray scaled and monochromatic, thus it can be displayed by the use of amplitude spatial light modulators to achieve real-time operation. The system provides a single output-plane result of the optical coherent addition of the separate channels' correlation outputs. At the output plane no electronic postprocessing is needed, and the detection decision is achieved simply by the application of threshold detection. Experimental results and computer simulations are presented to demonstrate the abilities of this system.

Color Pattern Recognition with Recombined Single Input Channel Joint Transform Correlator

“…However, the multi-channel single output color JTC has to take into account the separation between the input target image and the reference image. Deutsch [21] found that the separation between the input target image and the reference image for the same color must be the same and also larger than the sum of the widths of these images in order to prevent any unwanted overlapping between correlation outputs. To yield sharp correlation peaks, Alam et al proposed a fringe-adjusted JTC based on Newton-Raphson algorithm [22].…”

Coded Single Input Channel for Color Pattern Recognition in Joint Transform Correlator

“…For example, a spatial light modulator (SLM) is needed at each channel, two lenses are required at each channel, and an extra beam splitter and a mirror are also needed. The concept of multi-channel single output color JTC configuration was initially proposed by Deutsch to overcome such disadvantages [21]. However, the multi-channel single output color JTC has to take into account the separation between the input target image and the reference image.…”

“…However, the multi-channel single output color JTC has to take into account the separation between the input target image and the reference image. Deutsch [21] found that the separation between the input target image and the reference image for the same color must be the same and also larger than the sum of the widths of these images in order to prevent any unwanted overlapping between correlation outputs. To yield sharp correlation peaks, Alam et al proposed a fringe-adjusted JTC based on the Newton-Raphson algorithm [22].…”

Constrained optimization for color pattern recognition with a nonzero order joint transform correlator

“…In fact, it could be possible to find an arrangement of objects for all color channels at the input plane that would lead to the coherent addition of the three cross-correlation terms between the corresponding RGB color channels of the target and the input scene. To achieve this, Deutsch et al [8] introduced a multichannel single-output JTC. However, their concept led to massive zero-order parts composed of several autocorrelation terms that suffer from poor detection efficiency.…”