The use of CCD pixel binning in PIV measurements

Abstract

In this work, we study the effects of a CCD camera binning option, which increases camera frame rate throughput at the expense of loosing spatial resolution, on the Particle Image Velocimetry measurements. The camera frame rate defines upper bound on a speed of a flow a PIV system can measure. We have carried our experiments on the real images of the 1 µm size fluorescence polystyrene microparticles placed onto a thick quarts glass plate and illuminated with the high-power LED. The in-plane images were captured at various CCD binning factors and the distances between particles were calculated using cross-correlation analysis with a sub-pixel interpolation scheme based on the Gaussian regression. As a result of this study, we show that despite the decrease in the spatial resolution, the advantages of the pixel binning, such as increase in sensitivity and the total full frame rate, can be useful for LED illuminated PIV measurements, especially in laminar fluid flows.