Improved particle tracking velocimetry based on level set segmentation for measuring the velocity field of granular flow

Abstract Using traditional particle tracking velocimetry based on optical flow for measuring areas with large velocity gradient changes may cause oversmoothing, resulting in significant measurement errors. To address this problem, the traditional particle tracking velocimetry method based on an optical flow was improved. The level set segmentation algorithm was used to obtain the boundary contour of the region with large velocity gradient changes, and the non-uniform flow field was divided into regions according to the boundary contour to obtain sub-regions with uniform velocity distribution. The particle tracking velocimetry method based on optical flow was used to measure the granular flow velocity in each sub-region, thus avoiding the problem of granular flow distribution. The simulation results show that the measurement accuracy of this method is approximately 10% higher than that of traditional methods. The method was applied to a velocity measurement experiment on dense granular flow in silos, and the velocity distribution of the granular flow was obtained, verifying the practicality of the method in granular flow fields.