Comparison of envelope detection techniques in coherence scanning interferometry

Webpage : https://www.osapublishing.org/ao/abstract.cfm?URI=ao-55-24-6763

The aim of this work is to make a comparison of the most current signal processing techniques used to analyze the fringe signal in Coherence Scanning Interferometry (CSI), a major technique for optical surface roughness measurement. We focus here on classical AM-FM signal processing algorithms such as Hilbert Transform (HT), Five Sample Adaptive (FSA) and Continuous Wavelet Transform (CWT). We have recently also introduced a new family of compact and robust algorithms using the Teager Kaiser Energy Operator (TKEO). We propose an improved version of TKEO using the combination of different techniques of pre-filtering and demodulation processing to remove the noise and offset component, and to retrieve the fringe envelope to determine the surface height information. In particular, as a pre-filtering approach, we have focused on empirical mode decomposition (EMD) in combination with the Savitzky-Golay filter. An added Gaussian post-filtering is helpful for a precise peak extraction. The experimental results show that TKEO performs better than CWT in terms of computational time and provides a better surface extraction than the HT and FSA. Results have been obtained on synthetic and real data taken from a layer of resin on a silicon (substrate).

G. Gianto , F. Salzenstein , P. Montgomery

Applied Optics , Volume 55 , Number 24 , page 6763-6774 - 2016

@Article{2-GSM16,
 author = {Gianto, G. and Salzenstein, F. and Montgomery, P.},
 title = {Comparison of envelope detection techniques in coherence scanning interferometry},
 journal = {Applied Optics},
 number = {24},
 volume = {55},
 pages = {6763-6774},
 month = {Aug},
 year = {2016},
 doi = {doi.org/10.1364/AO.55.006763},
 x-international-audience = {Yes},
 x-language = {EN},
 url = {http://publis.icube.unistra.fr/2-GSM16}
}