Thread Pitch

The topic of this sample application is screw gauging. The image displays a screw with the relevant measuring lines.

The backlighting gives a clear contour image, from which first the complete screw is created as a separate object, then two corresponding teeth of the outer contour. A straight line connecting the tips of the teeth is computed and measured against the axis of the screw to determine the thread pitch. The advantage of this method is that the screw has to be aligned using only as much precision as is necessary to find the teeth on the contour.