Power law response of volume holographic pattern recognition to partial images

摘要

The response of a volume holographic pattern recognition system to partial versions of a reference image is investigated. Reference images used are arrays of circular apertures under uniform illumination. The arrays consist of three periodic grids, with different aperture diameters and spacing, and two arbitrary images. Partial versions of an image are generated by blocking apertures, resulting in fractional content R, where R is the ratio of remaining apertures to the total number of apertures. Recognition strength, in terms of reconstructed intensity, for five different images shows power law dependence on R. Exponents of the scaling functions depend on the nature of the reference image. The response of the holographic system is variable with respect to which apertures are present in the partial image, demonstrating a feature-specific recognition capability. Scale invariance is still observed even when a Gaussian beam is used for recording and recognition. (C) 2004 Elsevier B.V. All rights reserved.