A novel image pre-processing scheme for PIV of single- and two-phase flows over reflecting objects which does not require the use of additional hardware is discussed. The approach for single-phase flow consists of image normalization and intensity stretching followed by background subtraction. For two-phase flow, an additional masking step is added after the background subtraction. The effectiveness of the pre-processing scheme is shown for two examples: PIV of single-phase flow in spacer-filled channels and two-phase flow in these channels. The pre-processing scheme increased the displacement peak detectability significantly and produced high quality vector fields, without the use of additional hardware.
Deen, N. G., Willems, P., van Sint Annaland, M., Kuipers, J. A. M., Lammertink, R. G. H., Kemperman, A. J. B., ... van der Meer, W. G. J. (2010). On image pre-processing for PIV of sinlge- and two-phase flows over reflecting objects. Experiments in fluids, 49(2), 525-530. https://doi.org/10.1007/s00348-010-0827-y