Measuring Geometrical Parameters of Involute Spur Gears to Sub-pixel Resolution.

The problem of accurate determination of the position, orientation and width of involute spur gear teeth using a single front-lit image is addressed. The information is used to compute global measures of tooth concentricity and pitch variations across a gear wheel. The approach is based on the use of specialised filters which make maximum use of the grey level information available in the image. Tooth location consistent to ±0.04 pixels has been achieved in realistic images.