Adaptive filter to improve the performance of phase-unwrapping in digital holography

Digital holographic microscopy for recording and analysis of 3D images of etched tracks in LR-115 SSNTD

“…With the capture of only a single hologram the wave field of etched tracks can be completely reconstructed, so that optical sections of the detector at different depths can be reconstructed. Additional theoretical aspects and details of the experimental setup for the analysis of microscopic objects by DHM are described elsewhere [20][21][22][23].…”

Non-destructive strain determination based on phase measurement and radial basis function

“…For example, denoising was done on intensity by spin filters [8] and partial differential equation (PDE) based methods [9]. Windowed Fourier transform (WFT) [10], regularized quadratic cost function (RQCF) [11] and sine/cosine average filtering [12] were applied to filter the wrapped phase.…”

“…Wang et al introduced the RBF interpolation to the fringe skeleton method and RBF was used to filter original ESPI fringes [17]. However, sometimes it is difficult to distinguish between signal and noise in the original fringe while contaminations can be identified from the unwrapped phase map [12]. Furthermore, the result calculated from the fringe after RBF interpolation would not be creditable if more noise points were sampled as signals.…”

Piecewise polynomial phase approximation approach for the analysis of reconstructed interference fields in digital holographic interferometry

“…It is simply calculated using the arctan function from the reconstructed interference field. However, phase calculated in this manner is always wrapped and often noisy, making it mandatory to employ filtering and 2-D phase unwrapping procedures [2,3,4,5,6,7]. These reasons motivated researchers to develop different strategies or new analysis techniques [8,9,10,11,12].…”