High precision deformation measurement by digital phase shifting holographic interferometry

Abstract

A digital phase shifting technique capable of quantitatively determining the phase of holographic interferometric displacement fringes is presented. This technique uses computer control to take data and calculate surface deformation. The phase value at each detector point can be calculated by taking four successive intensity data frames with the reference phase shifted between each frame. The displacement fringe order number can be assigned by adding or subtracting 2r from a data point until the phase difference between adjacent data points is less than ir. Experimental results show that this technique can precisely determine a fraction of a fringe with an accuracy of +1'.

Statistic optics discussion on the formula of digital holographic 3D surface profiling measurement

“…Digital holography 3D surface profile measurement has been applied to the 3D profile measurement of small objects and particles, such as MEMS characteristics and 3D micro-particles imaging [8][9][10][11]. Therefore, the discussions presented in this paper have valuable references for increasing the measurement precision in the digital holography 3D surface profile measurement technology.…”

<title>Defect detection on composite materials by phase-step interferometry</title>

“…I(x,y)=A(x,y)+B(x,y)cosp(x,y) (1) Here, A(x,y) is background intensity, B(x,y) is fringe contrast, P(x,y)is the phase value to be measured at point (x,y). Assume in the phase step system, the total phase shift is 2B by Here, m(x,y)=B(x,y)/A(x,y), r0,l,2 ... N is step number.…”

Active Optical Range Imaging Sensors

“…Thalmann and Dandliker [1985] and Dandliker and Thalmann [1985] examine two-reference beam interferometry and two-wavelength contouring for quasi-heterodyne and heterodyne systems. Chang et al [1985] did experiments in digital phase-shifted holographic interferometry to eliminate the need to calibrate the phase shifter as in Hariharan et al [1983]. They claim an accuracy of 2 nm over a 300-nm depth of field.…”