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Proceedings Paper

Minimizing the effects of threshold setting errors, detection, shading, and noise errors in fringe patterns
Author(s): Jerzy M. Woznicki; Grzegorz Kukielka
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Paper Abstract

This paper presents an overview of methods of error elimination during image processing and analysis, and more specially ofthe problems ofsetting the threshold errors, shading and noise. Of all the steps involved in measuring objects in an image, setting the threshold is the one which should be considered most careftilly. There are described following errors: threshold setting error, the offset threshold error, "halo" error and elimination methods. The process of setting the detection level should be standardised, whichever technique is adopted, and some form of check on a standard specimen should be incorporated into the image analysis routine if at all practicable. Shading is the best dealt with by using a shading correction step in the image processing, but operator can help by ensuring that illumination system of microscope for example is correctly centred, that specimen is flat, that the lamps on macroviewer all have the same wattage and are at the same distance from the specimen. Shading can be asymmetrical, and it can be present in the specimen itself as well as being introduced in the optical system. Noise is a function of system design, with no room for operator of the system to affect it, except by increasing the gain of the video amplification. Noise is minimised by operating the system at the optimum conditions of incident lighting.

Paper Details

Date Published: 17 July 1996
PDF: 7 pages
Proc. SPIE 2860, Laser Interferometry VIII: Techniques and Analysis, (17 July 1996); doi: 10.1117/12.276328
Show Author Affiliations
Jerzy M. Woznicki, Warsaw Univ. of Technology (Poland)
Grzegorz Kukielka, Warsaw Univ. of Technology (Poland)

Published in SPIE Proceedings Vol. 2860:
Laser Interferometry VIII: Techniques and Analysis
Malgorzata Kujawinska; Ryszard J. Pryputniewicz; Mitsuo Takeda, Editor(s)

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