Experimental evaluation of a 3D wavelet-based phase recovery method in temporal speckle pattern interferometry.

We test the performance of a phase recovery method based on a three-dimensional directional wavelet transform applied to the intensity signal measured by temporal speckle pattern interferometry (TSPI). We present and discuss several sources of uncertainty by analyzing experimental datasets recorded for an in-plane interferometer without introducing a temporal carrier. The dynamic phase data measured with the proposed method are compared with those obtained from the well-known one-dimensional Fourier transform phase recovery technique.

Measurement of nanometric displacements by correlating two speckle interferograms.

This paper presents a method to measure nanometric displacement fields using digital speckle pattern interferometry, which can be applied when the generated correlation fringes show less than one complete fringe. The method is based on the evaluation of the correlation between the two speckle interferograms generated by both deformation states of the object. The performance of the proposed method is analyzed using computer-simulated speckle interferograms.

Tilt scanning interferometry: a numerical simulation benchmark for 3D metrology.

Tilt scanning interferometry (TSI) is a novel experimental technique that allows the measurement of multicomponent displacement fields inside the volume of a sample. In this paper, we present a simulation model that allows for the evaluation of the speckle fields recorded in TSI when this technique is applied to the analysis of semitransparent scattering materials. The simulation is based on the convolution of the optical impulsive response of the optical system and the incident field amplitude.

Speckle activity images based on the spatial variance of the phase.

We propose the display of the local spatial variance of the temporal variations of the phase as an activity descriptor in dynamic speckle images. The spatial autocorrelation of the speckle intensity is calculated in sliding windows, and an estimation of the variance of the phase variations in each region of the sample is determined. The activity images obtained in this way depict some interesting features and in some cases they could be related to physical magnitudes in the samples.

Phase measurement in temporal speckle pattern interferometry: comparison between the phase-shifting and the Fourier transform methods.

The measurement of dynamic displacements by use of speckle pattern interferometry and temporal phase unwrapping allows for the evaluation of large-object displacement fields without the propagation of spatial unwrapping errors. If a temporal carrier is introduced in one of the beams of the interferometer, phase data for whole-object displacement can be retrieved by use of a temporal phase-shifting method or a temporal Fourier transformation approach. We present a comparison between both methods of temporal phase measurement in terms of precision and execution speed.