Studying Disk Movements by Novel Image-Analysis Method

An image-analysis method developed to study granular flow, the accumulating particle trajectories (APT) method, is shown to be a versatile tool to study the movements of disks. The moving disks, which are provided with suitable dot patterns, are video-recorded and the recorded sequences are analyzed to provide trajectories of the disks and the dots, thus making it possible to study both translational and rotational movements. It is also possible to introduce time markers in the trajectories. Up to eight images per second can be analyzed. The filtering necessary to attenuate electronic noise in the video equipment is performed as time filtering between consecutive images and is very efficient. The method's demands for processing power are very moderate and, therefore, particle movements during time spans corresponding with thousands of video frames can be easily presented as analysis results. The method can be implemented at relatively low cost.