Journal ArticleDOI
Use of two wavelengths in microscopic TV holography for nondestructive testing
Paul Kumar Upputuri,Somasundaram Umapathy,Manojit Pramanik,M. P. Kothiyal,Krishna Mohan Nandigana +4 more
TLDR
In this paper, a two-wavelength TV holography using a single-chip color charge-coupled device (CCD) camera for NDT of microspecimens is presented.Abstract:
Single wavelength TV holography is a widely used whole-field noncontacting optical method for nondestructive testing (NDT) of engineering structures. However, with a single wavelength configuration, it is difficult to quantify the large amplitude defects due to the overcrowding of fringes in the defect location. In this work, we propose a two wavelength microscopic TV holography using a single-chip color charge-coupled device (CCD) camera for NDT of microspecimens. The use of a color CCD allows simultaneous acquisition of speckle patterns at two different wavelengths and makes the data acquisition as simple as that of the single wavelength case. For the quantitative measurement of the defect, an error compensating eight-step phase-shifted algorithm is used. The design of the system and a few experimental results on small-scale rough specimens are presented.read more
Citations
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Proceedings ArticleDOI
Simultaneous profiling of optically smooth and rough surfaces using dual-wavelength interferometry
TL;DR: In this article, a dual-wavelength approach to measure surface profile of both smooth and rough surfaces simultaneously is presented, where the wrapped phases at each wavelength are calculated and subtracted to generate contour phase map.
References
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Journal ArticleDOI
Two-wavelength interferometry.
TL;DR: An extension of the static technique to real- time dynamic testing is proposed and an operational variable-sensitivity interferometer utilizing the real-time technique is described.
Journal ArticleDOI
Digital Speckle Pattern Interferometry & Related Techniques
TL;DR: Digital Speckle Pattern Interference (DSPI) is a class of important interferometric techniques such as TV holography or phase shifting pattern interferometry, all of which involve similar optical and electronic principles as discussed by the authors.
Journal ArticleDOI
Talbot images of wavelength-scale amplitude gratings
TL;DR: Detailed analysis of the impact and the interplay of various diffraction orders to the formation of Talbot images provides new insights into the fundamental properties of gratings that often find use in applications such as, e.g., lithography, sensing, and imaging.
Journal ArticleDOI
White light interferometry for surface profiling with a colour CCD
TL;DR: In this article, a white light interferometer with a colour CCD camera is discussed, where interference intensity information from the three channels of the color CCD simulating three-wavelength measurement is accessed.