Abstract
White light interferometry is a widely used tool to extend the unambiguous measurement range of a monochromatic interferometer. In this work, we discuss Hilbert transformation analysis of a single white light interferogram acquired with a single-chip color CCD camera for step height measurement which lies beyond the unambiguous range of the monochromatic interferometry. The color interferogram is decomposed and phase maps for red, green, and blue components are calculated independently using Hilbert transformation. This procedure makes the measurement faster, simpler, and cost-effective. The usefulness of the technique is demonstrated on micro-sample.
Highlights
The single wavelength phase shifting interferometry (SWPSI) offers excellent vertical resolution and sensitivity [1,2,3,4,5,6]
The spectrally resolved white light interferometry [16,17], on the other hand gives only a line profile of the object, the requirement on number of frames is similar to the single wavelength phase shifting interferometry
The signals from the R G B channels are associated with non-uniform bias and are modulated
Summary
The single wavelength phase shifting interferometry (SWPSI) offers excellent vertical resolution and sensitivity [1,2,3,4,5,6]. Phase shifting white light interferometry (PSWLI) combined with a 3-chip colour CCD camera can make the data acquisition as simple as in single wavelength case [18]. A 3-chip colour CCD can give high resolution, but is costly This technique requires typically 5 to 8 phase shifted frames for phase evaluation [18,19,20]. We discuss Hilbert transform fringe analysis of a single white light interferogram acquired with a single-chip colour CCD camera for large step-height measurement. The present technique does not require phase shifting method, multiple-wavelength laser sources, or 3-chip CCD for surface profiling. It makes the measurement faster, simpler and less expensive. The theoretical background of Hilbert transformation fringe analysis of colour fringes and experimental results on a micro-specimen are presented
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
