A new image processing algorithm for three-dimensional angular velocity measurement and its application in a granular avalanche
Journal
Advanced Powder Technology
Journal Volume
29
Journal Issue
3
Pages
506-517
Date Issued
2018
Author(s)
Lin, C.-C.
Abstract
This work proposes a novel algorithm to extract three-dimensional angular velocity of a sphere from a sequence of high-speed digital images of this sphere and its marker stickers. This technique can capture the angular velocity ω of a sphere made to move at a specific angle from the camera by an offset DC motor and its speed |ω| with an error lower than 5%. The method is then applied to measure individual grain rotation dynamics at the boundary during a bulk avalanche to extract the instantaneous contour of each angular velocity component which is in qualitative agreement to that reported from a complementing discrete element simulation. The angular velocity of individual grains |ωp| is further analyzed with its local packing density and configuration to confirm that the sudden rise of |ωp| is always accompanied by local dilatation upon particle rearrangement.
Type
journal article