Enhancement of Particle Image Velocimetry Images

Abstract: Particle Image Velocimetry (PIV) is a method to visualize the flows and quantitatively map the flows. It is used to obtain the instantaneous velocity, vorticity, divergence, shear in fluids, etc. Laser Doppler velocimetry and hot wire anemometry are other techniques that are used to measure the flow. The main difference between PIV and those techniques is that PIV produces two-dimensional or three-dimensional vector fields. PIV uses two sequences of images (frames) and the frames are split into a large number of interrogation windows. The displacement vector is calculated for each window with the help of auto-correlation or cross-correlation techniques. Missing data during these processes leads to inaccurate results. To overcome this, preprocessing techniques such as histogram equalization and intensity clipping are used to enhance the PIV images to obtain accurate results.