An application of image processing in the study of sediment motion

The influence of turbulence on the entrainment of sediment particles from a plane mobile bed was investigated using image processing techniques to rec ord sediment particle motion in an experimental flume while simultaneously monitoring the turbulence characteristics of the flow. The importance of th e image processing techniques applied arise from the use of the collected i mages for determination of the area of sediment entrained and the instantan eous particle velocity. A subtraction technique was used to derive the difference between consecuti ve images, from which the number of particles entrained in an increment of time could be determined. A cross correlation was applied to find if a rela tion between the number of entrained particles and the instantaneous shear stress in sweep events existed. A significant correlation with was found fo r this relation. From the results obtained, the exceedance probability of t he area entrained was found to correlate with the exceedance probability of instantaneous shear stress in a sweep event. Image processing was found to be a useful technique for the analysis of exp erimental data and fundamental to this study aimed at investigating the ent rainment mechanisms for sediment particles.