Correction of Scanning Steps to Improve Accuracy in Interferometric Profilometer

Abstract

In scanning interferometry of longitudinal shift, an uncertainty of required phase shift performance leads to a measurement error. Such uncertainty can be caused by external factors (vibrations, air turbulence in measuring area etc.) as well as inaccuracy of the scanning system. The method for calculating the phase shift between interferograms, which allows reducing the measurement error, is proposed. The results of numerical and full scale experiments are presented.

A Novel Quadrature Signal Estimation Method for a Planar Capacitive Incremental Displacement Sensor

“…In the PSA scheme, the X-Y displacement signals are obtained by a particular arctangent function as shown in (14) and (15). Effects of phase-shift errors on X-Y quadrature waveforms are also removed.…”

“…Commonly, PCIDS signals are squared into electrical pulses, the number of which is counted to determine displacement information [11]- [15]. Tan et al introduced an interpolation method based on constructing and squaring a set of high-order sinusoids.…”