25 October 1989 Real And Positive Filter Based On Circular Harmonic Expansion
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Proceedings Volume 1134, Optical Pattern Recognition II; (1989) https://doi.org/10.1117/12.961630
Event: 1989 International Congress on Optical Science and Engineering, 1989, Paris, France
A real and positive filter for pattern recognition is presented. The filter, based on the circular harmonic (CH) expansion of a real function, is partially rotation invariant. As it is real and positive, the filter can be recorded on a transparency as an amplitude filter. Computer simulations of character recognition show a partial rotation invariance of about 40°. Optical experiments agree with these results and with acceptable discrimination between different characters. Nevertheless, due to experimental difficulties, the method is onerous for use in general pattern recognition problems.
© (1989) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Carlos Ferreira, Carlos Ferreira, Javier Garcia, Javier Garcia, Enrique Tajahuerce, Enrique Tajahuerce, "Real And Positive Filter Based On Circular Harmonic Expansion", Proc. SPIE 1134, Optical Pattern Recognition II, (25 October 1989); doi: 10.1117/12.961630; https://doi.org/10.1117/12.961630

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