Ice cross sectional profile measurement based on line structured light

To realize the ice cross sectional profile measurement in a non-contact way,a line structured light based measurement is adopted.Firstly a laser sheet is proj ected vertically on the ice surface.Secondly,the image of the deformed laser line on the ice surface is captured by a camera.Finally,the 3D coordinates of the laser line on the ice surface are calculated upon the cal-ibrated geometric relationship between the laser sheet and the camera.Then the proj ection of these 3D coordinates on the laser sheet is the ice cross sectional profile.In this paper,a simple line structured light measurement device and a measurement procedure are developed.To deal with the problem of the low image contrast due to the low reflected laser energy on ice,a novel laser line center extraction method is provided.In the experiments,an ice sheet frozen by a re-frigerator with its radius known is measured.The maximum relative error is 0.052,and the mean relative error is 0.018.A preliminary measurement result of the icing on two elements air-foil generated in an icing wind tunnel is also obtained.It lays a technical foundation for the 3D ice shape online measurement during ice accretion in icing wind tunnels in the future.