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Remote nocturnal bird classification by spectroscopy in extended wavelength ranges

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Author

Summary, in English

We present optical methods at a wide range of wavelengths for remote classification of birds. The proposed methods include eye-safe fluorescence and depolarization lidar techniques, passive scattering spectroscopy, and infrared (IR) spectroscopy. In this paper we refine our previously presented method of remotely classifying birds with the help of laser-induced beta-keratin fluorescence. Phenomena of excitation quenching are studied in the laboratory and are theoretically discussed in detail. It is shown how the ordered microstructures in bird feathers induce structural "colors" in the IR region with wavelengths of around 3-6 mu m. We show that transmittance in this region depends on the angle of incidence of the transmitted light in a species-specific way and that the transmittance exhibits a close correlation to the spatial periodicity in the arrangement of the feather barbules. We present a method by which the microstructure of feathers can be monitored in a remote fashion by utilization of thermal radiation and the wing beating of the bird. (C) 2011 Optical Society of America

Publishing year

2011

Language

English

Pages

3396-3411

Publication/Series

Applied Optics

Volume

50

Issue

20

Document type

Journal article

Publisher

Optical Society of America

Topic

  • Atom and Molecular Physics and Optics
  • Biological Sciences

Status

Published

ISBN/ISSN/Other

  • ISSN: 2155-3165