Digital in-line holography in thick optical systems: application to visualization in pipes.
We apply digital in-line holography to image opaque objects through a thick plano-concave pipe. Opaque fibers and opaque particles are considered. Analytical expression of the intensity distribution in the CCD sensor plane is derived using a generalized Fresnel transform. The proposed model has the ability to deal with various pipe shapes and thicknesses and compensates for the lack of versatility of classical digital in-line holography models. Holograms obtained with a 12 mm thick plano-concave pipe are then reconstructed using a fractional Fourier transform. This method allows us to get rid of astigmatism. Numerical and experimental results are presented.
Verrier
Nicolas
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Groupe d'Optique et d'Optoélectronique, UMR-6614 CORIA, Avenue de l'Université, 76801 Saint-Etienne du Rouvray Cedex, France.
Coëtmellec
Sébastien
S
Brunel
Marc
M
Lebrun
Denis
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