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Journal of Electronic Imaging

Efficient focus assessment for a computer vision-based Vickers hardness measurement system
Author(s): Andreas Maier; Georg Niederbrucker; Sebastian Stenger; Andreas Uhl
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Paper Abstract

A large variety of computationally lightweight functions used for assessing image sharpness in the spatial domain is evaluated for application in a passive autofocus system in the context of microindentation-based Vickers hardness testing. Alternatively, the file size of compressed JPEG images is proposed to determine image sharpness. The functions are evaluated on a significant dataset of microindentation images with respect to their properties required for focus search and sharpness assessment, their robustness to downsampling the image data, and their computational demand. Experiments suggest that of all spatial domain techniques considered, the simple Brenner autofocus function is the best compromise between accuracy and computational effort, while JPEG file size is a versatile solution when the application context allows.

Paper Details

Date Published: 15 May 2012
PDF: 15 pages
J. Electron. Imag. 21(2) 021114 doi: 10.1117/1.JEI.21.2.021114
Published in: Journal of Electronic Imaging Volume 21, Issue 2
Show Author Affiliations
Andreas Maier, Univ. Salzburg (Austria)
Georg Niederbrucker, Univ. Salzburg (Austria)
Sebastian Stenger, Univ. Salzburg (Austria)
Andreas Uhl, Univ. Salzburg (Austria)

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