Predicting local material thickness from steady-state ultrasonic wavefield measurements using a convolutional neural network.

Acoustic steady-state excitation spatial spectroscopy (ASSESS) is a full-field, ultrasonic non-destructive evaluation (NDE) technique used to locate and characterize defects in plate-like structures. ASSESS generates a steady-state, single-tone ultrasonic excitation in a structure and a scanning laser Doppler Vibrometer (LDV) measures the resulting full-field surface velocity response. Traditional processing techniques for ASSESS data rely on wavenumber domain analysis.

Simulating translation-induced laser speckle dynamics in photon Doppler velocimetry.

Historically, single-beam optical velocimetry has been limited to measuring only the component of velocity along the beam. However, theoretical work and recent experimental results have shown that laser speckle dynamics may be exploited to measure lateral motion, thereby gaining information about surface dynamics across an additional degree of freedom. In the use of photon Doppler velocimetry (PDV), this new information is considered "free" in that it is already contained within the PDV signal, needing only to be extracted and interpreted correctly.

Three-wavelength electronic speckle pattern interferometry with the Fourier-transform method for simultaneous measurement of microstructure-scale deformations in three dimensions.

We present the simultaneous measurement of three-dimensional deformations by electronic speckle pattern interferometry using five object beams and three colors. Each color, corresponding to an orthogonal direction of displacement, is separated through dichroic filtering before being recorded by a separate CCD camera. Carrier fringes are introduced by tilting the beam path in one arm of each of the three interferometers.