Paper
18 January 1985 Imaging Properties Of Random Phase Diffusers For Coherent Imaging Systems
Marek Kowalczyk
Author Affiliations +
Proceedings Volume 0473, Symposium Optika '84; (1985) https://doi.org/10.1117/12.942397
Event: Symposium Optika '84, 1984, Budapest, Hungary
Abstract
A number of coherent systems exist for whichillp would be desirable to illuminate an object with a beam of randomly modulated phase. Usually for this purpose we put together the object and random phase diffuser, e.g. ground glass, at its back side. In the case of uniformly illuminated trivial object whose amplitude transmittance equals unity we observe in the image plane intensity fluctuations which correspond to some extent to the random relief of illuminating wavefront. By imaging properties of random phase diffuser we mean statistical propoerties of these fluctuations, especially their average contrast. In this work we consider imaging properties of diffusers which are set in the wide-band imaging system for which ratio, point spread function area divided by autocorrelation area of diffuser complex transmittance, is less than unity. We derive the formulae which describe intensity fluctuation in the image plane in terms of phase distribution and its first and second spatial derivatives in the object plane. Above formulae are derived for the low-pass filtering, particular case of high pass filtering, and for the case of not perfect image focusing. Then we employ these formulae for calculation the average contrast of noise pattern in the image plane when photographically formed strong diffuser with small standard deviation of surface roughness (≈ 0.58λ) is used.
© (1985) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Marek Kowalczyk "Imaging Properties Of Random Phase Diffusers For Coherent Imaging Systems", Proc. SPIE 0473, Symposium Optika '84, (18 January 1985); https://doi.org/10.1117/12.942397
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KEYWORDS
Diffusers

Imaging systems

Image filtering

Linear filtering

Speckle

Speckle pattern

Transmittance

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