Abstract

Contrast improvement in a coherent image enhancement system by very low spatial frequency attenuation is shown, demonstrating possible errors incurred by incorrect attenuation. A novel way to achieve a continuous range of low frequency attenuation is introduced. The variable attenuation is produced by constructing the spatial filter from polarizing material and altering the relative polarization between the object transparency illumination and the spatial filter. This technique gives the observer control over a continuous change in contrast enhancement and greatly increases the versatility of low frequency spatial filtering. Coherent imaging systems are usually contaminated by noise, and a simple way to reduce the noise content in the image is shown.

© 1977 Optical Society of America

Spatial frequency filtering and its application to microscopy

Peter J. S. Hutzler
Appl. Opt. 16(8) 2264-2272 (1977)

Microscope adapted for the generation of various contrast types: theory and experiment

H. de Lang and N. H. Dekkers
Appl. Opt. 16(8) 2215-2222 (1977)

Real-time transmission of a 3-D image using volume scanning and spatial modulation

J. Hamasaki, Y. Nagata, H. Higuchi, and M. Okada
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MTF evaluation with optical matched filters

Alex Grumet
Appl. Opt. 16(1) 154-159 (1977)

White light optical processing and holography

E. Leith and J. Roth
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