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Proceedings Paper

Axial-resolution in depth from focus digital holography
Author(s): Joseph van Rooij; Jeroen Kalkman
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Paper Abstract

We use digital holography to quantify surface topography of rough objects in full-field. We calculate the variance of the intensity image as a focus metric over a set of reconstruction distances for each pixel, which results in a focus metric curve. The distance where the variance peaks is an estimate for the depth. First we analyze the lateral resolution of this method using the Talbot effect and argue that sub-mm axial resolution is feasible. Then, using a Michelson setup without magnifying optics or lateral scanning we experimentally demonstrate that sub-mm FWHM width of the focus curve can be achieved. This is significantly better than what was previously reported using digital holography and could make this technique useful for characterising objects in art and machine vision.

Paper Details

Date Published: 26 June 2017
PDF: 7 pages
Proc. SPIE 10335, Digital Optical Technologies 2017, 103351F (26 June 2017); doi: 10.1117/12.2270295
Show Author Affiliations
Joseph van Rooij, Technische Univ. Delft (Netherlands)
Jeroen Kalkman, Technische Univ. Delft (Netherlands)

Published in SPIE Proceedings Vol. 10335:
Digital Optical Technologies 2017
Bernard C. Kress; Peter Schelkens, Editor(s)

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