Arrangement for detecting light sources
AssigneeThomson-CSF
InventorsJean-Claude Reymond, Alain Bellissant
Life of this patent
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Abstract
An arrangement which enables the presence in an observed field of a light source whose radiation spectrum is known to be detected with a high signal to noise ratio. It includes an acousto-optical tunable filter controlled to scan through the expected spectrum of the source periodically and preferably linearly. The photo-detected signals are processed by a high-pass filter which removes the D.C. component due to ambient interference radiation and provides a periodic signal which correspond to the observed light source. The arrangement applies, in particular, to the angular location of luminous targets.
Claims8
An arrangement for detecting a light source having a known expected radiation spectrum in an observed field, comprising:
- optical receiving means for focusing incident light radiation originating from said field and consisting of ambient interference radiation and said expected radiation;
- optical filtering means comprising an acousto-optical tunable filter controlled by a control device to scan periodically and according to a predetermined law of change in frequency with time the frequency of the filter through an operating band which corresponds substantially to that of the said expected spectrum so as successively to filter the various received wavelengths therein;
- opto-electrical detection means for detecting said filtered and focused incident radiation;
- and a processing circuit for processing the detected signals and comprising a high-pass filter of predetermined cut-off frequency to eliminate the D.C. component due to the ambient interference radiation and to provide a periodic useful signal due to radiation from said source.
Dependencies are inferred from the claim text.