Confocal signal evaluation algorithms for surface metrology
uncertainty and numerical efficiency
Abstract
Confocal microscopy is one of the dominating measurement techniques in surface metrology, with an enhanced lateral resolution compared to alternative optical methods. However, the axial resolution in confocal microscopy is strongly dependent on the accuracy of signal evaluation algorithms, which are limited by random noise. Here, we discuss the influence of various noise sources on confocal intensity signal evaluating algorithms, including center-of-mass, parabolic least-square fit, and cross-correlation-based methods. We derive results in closed form for the uncertainty in height evaluation on surface microstructures, also accounting for the number of axially measured intensity values and a threshold that is commonly applied before signal evaluation. The validity of our results is verified by numerical Monte Carlo simulations. In addition, we implemented all three algorithms and analyzed their numerical efficiency. Our results can serve as guidance for a suitable choice of measurement parameters in confocal surface topography measurement, and thus lead to a shorter measurement time in practical applications.
Details
- Organisationseinheit(en)
-
Hannoversches Zentrum für Optische Technologien (HOT)
Institut für Mess- und Regelungstechnik
- Typ
- Artikel
- Journal
- Applied Optics
- Band
- 56
- Seiten
- 5920-5926
- Anzahl der Seiten
- 7
- ISSN
- 1559-128X
- Publikationsdatum
- 17.07.2017
- Publikationsstatus
- Veröffentlicht
- Peer-reviewed
- Ja
- ASJC Scopus Sachgebiete
- Atom- und Molekularphysik sowie Optik, Ingenieurwesen (sonstige), Elektrotechnik und Elektronik
- Elektronische Version(en)
-
https://doi.org/10.1364/AO.56.005920 (Zugang:
Geschlossen
)
