Measurement of three-dimensional velocity profiles using forward-scattering particle image velocimetry (FSPIV) and neural net pattern recognition

Effects of Ammonia Plasma Treatment on the Electrical Properties of Plasma-Enhanced Chemical Vapor Deposition Amorphous Hydrogenated Silicon Carbide Films

“…Therefore, it is advantageous to carry out bespoke tuning of the CCD camera, including switching to manual gain from automatic gain, to exploit to the full the dynamic range available from the CCD. Finally, predictions using GLMT confirmed the observation made by other authors [19][20][21][22][23] that particle images on either side of the focus plane are different.…”

“…the accuracy of out-of-plane position estimation, for the image above was estimated to be 5 µm out of plane. This accuracy can be increased at the cost of having a diminished region of interest [23]. For many velocimetry applications, for which the magnification is of the order of 1-3, the potential accuracy of this method is estimated to be 20-30 µm, using an approach of comparing predicted and experimental images and a Nelder-Mead optimization, though this may be increased with more sophisticated approaches to optimization.…”

“…An experimental 18 µm glass sample image is quantitatively compared with the calculated image for a Gaussian wavefront in forward scattering. This sample image in this viewing configuration has been chosen and described by a number of other authors [19][20][21][22][23] and therefore was chosen as the sample case for the present work.…”

Robust genetic algorithm for high-accuracy particle position estimation in three-dimensional particle image velocimetry applications

“…8,22,23 Moreover, the method demonstrated a capability to identify contaminant seeding particles, which typically do not satisfy flow-following criteria and therefore increase error.…”

“…To achieve an initial estimate of the z coordinate, a conventional neural net was constructed, broadly similar to one described previously, 8 while a centroid estimate was employed to yield a first estimate of in-plane position. The overall light intensity estimate can be obtained by calibration, and so this was taken as a known subject to an experimental error.…”