Journal ArticleDOI
Optical pattern recognition using circular harmonic expansion
Yuan-Neng Hsu,Henri H. Arsenault +1 more
TLDR
Experimental results with simple photographic objects show that targets with different locations and orientations can be simultaneously recognized by the optical system.Abstract:
Presented in this paper is an optical implementation of a shift- and rotation-invariant pattern recognition technique. A computer-generated hologram is designed to match with one of the circular harmonic components of the target. Experimental results with simple photographic objects show that targets with different locations and orientations can be simultaneously recognized by the optical system.read more
Citations
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Journal ArticleDOI
Minimum average correlation energy filters
TL;DR: The synthesis of a new category of spatial filters that produces sharp output correlation peaks with controlled peak values is considered, and these filters are referred to as minimum average correlation energy filters.
Journal ArticleDOI
Symmetric phase-only matched filtering of Fourier-Mellin transforms for image registration and recognition
TL;DR: A new method to match a 2D image to a translated, rotated and scaled reference image using symmetric phase-only matched filtering to the FMI descriptors, which guarantees high discriminating power and excellent robustness in the presence of noise.
Journal ArticleDOI
Performance measures for correlation filters.
TL;DR: It is shown that the POF appears to provide a good compromise between noise tolerance and peak sharpness, with the help of a new family of filters called fractional power filters (FPFs).
Journal ArticleDOI
Tutorial survey of composite filter designs for optical correlators.
TL;DR: A tutorial survey is presented of the many composite filter designs proposed for distortion-invariant optical pattern recognition and remarks are made regarding areas for further investigation.
Journal ArticleDOI
Unconstrained correlation filters
TL;DR: To optimize the filter's performance, the usual hard constraints on the outputs in the synthetic discriminant function formulation are removed, and the resulting filters exhibit superior distortion tolerance while retaining the attractive features of their predecessors.
References
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Journal ArticleDOI
Representation of a Function by Its Line Integrals, with Some Radiological Applications
TL;DR: In this paper, a method for finding a real function in a finite region of a plane given its line integrals along all straight lines intersecting the region was given, and the solution found is applicable to three problems of interest for precise radiology and radiotherapy: (1) the determination of a variable x-ray absorption coefficient in two dimensions, (2) the distribution of positron annihilations when there is an inhomogeneous distribution of the positron emitter in matter, and (3) a variable density of matter with constant chemical composition, using the energy loss
Journal ArticleDOI
Binary Fraunhofer Holograms, Generated by Computer
Adolf W. Lohmann,D. P. Paris +1 more
TL;DR: A theory for binary holograms is developed that is equivalent in terms of image reconstruction with ordinary holograms, proven theoretically and verified experimentally.
Journal ArticleDOI
Rotation-invariant digital pattern recognition using circular harmonic expansion.
TL;DR: A new method has been developed for rotation-invariant pattern recognition using one component of the circular harmonic expansion of the target in the preparation of the reference by FFT and multiplication in the frequency domain.
Journal ArticleDOI
Hybrid optical processor for pattern recognition and classification using a generalized set of pattern functions.
James R. Leger,Sing H. Lee +1 more
TL;DR: An analysis on the SNR of the processor employing the coded-phase technique, on the diffraction efficiencies of computer-generated filters (amplitude superposition) vs conventional filters (intensity superposition), and on the number of pattern functions required for a certain recognition task are provided.
Journal ArticleDOI
Optical reconstruction from projections via circular harmonic expansion
E. W. Hansen,Joseph W. Goodman +1 more
TL;DR: In this article, a new optical method for reconstructing a two-dimensional object from one-dimensional projections of that object has been proposed, which has wide application in such fields as computerized tomography, testing and measurement, and radio astronomy.