Machine vision for ice layer thickness measurements

A patented technique for remotely measuring layer thickness of transparent fluids and solids on surfaces has been incorporated into Canpolar East's Smart Camera (VE-262) and been validated for measurement of ice layer thickness. This application addresses the need for reliable detection of icing on aircraft. The thickness measurement technique is carried out by directing a laser beam at the surface with the ice layer. A pattern of illumination appears on the surface as a result of internal reflection of the laser light within the ice layer. The layer thickness is calculated by a simple formula involving the size of the image pattern and the refractive index of layer material. The system was tested using a wedge-shaped ice sample with a maximum thickness of about 10 mm. The data indicated a system measurement accuracy of /spl plusmn/0.1 mm.