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Proceedings Paper

Synthesis of Fourier holograms for recognition of radiation sources with continuous spectra by dispersive correlators
Author(s): D. Yu. Molodtsov; V. G. Rodin; S. N. Starikov
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Paper Abstract

Dispersive correlators have been proposed previously for solving problems of recognition of radiating objects in real time. Correlation signals are formed by radiation of analyzed object during its interaction with spatial filter. Most difficult recognition case is when spectrum of input radiation is continuous (non-line spectrum). Method of synthesis of Fourier holograms for their using in dispersive correlators as spatial filters is developed in this work. Spectral ranges, in which values of components of radiation are greater than predetermined threshold for reference spectrum, were determined. Entrance slit used as reference object. Next, spatial image of spectrum, which is a set of images of object (slit), was formed. Amount of object images and its sizes are determined with selected wavelength ranges. Fourier hologram of this image was computer synthesized and had 2048x2048 pixels. Then this hologram was binarized and printed using laser imagesetter with 100 dots/mm resolution. In this work the scheme of the dispersive correlator with single Fourier-objective was used. Correlation signals for different spectra were experimentally formed. LEDs, including RGB-LED with ability of dynamically changing of composition of radiation spectrum, were used as radiation sources. Post-processing operations, which provide independence of recognition results from radiation source power and holograms diffraction efficiency, were defined. Three methods of normalization of correlation signal for identification signal obtaining were experimentally tested and compared. These methods are normalization to radiation power in zero, first, and both of these diffraction orders. Experimental results on identification of test sources with non-line radiation spectra are obtained. They show successful recognition of used LED sources of different colors. Average ratio of spectra coincidence signal to mismatch signal was 4.6 at relative spectral resolution of used setup equaled to 0.004.

Paper Details

Date Published: 8 May 2015
PDF: 8 pages
Proc. SPIE 9508, Holography: Advances and Modern Trends IV, 950812 (8 May 2015); doi: 10.1117/12.2182281
Show Author Affiliations
D. Yu. Molodtsov, National Research Nuclear Univ. MEPhI (Russian Federation)
V. G. Rodin, National Research Nuclear Univ. MEPhI (Russian Federation)
S. N. Starikov, National Research Nuclear Univ. MEPhI (Russian Federation)

Published in SPIE Proceedings Vol. 9508:
Holography: Advances and Modern Trends IV
Miroslav Hrabovský; John T. Sheridan; Antonio Fimia, Editor(s)

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