Optical triangulation has been successfully employed for obtaining three-dimensional (3-D) measurements of surfaces. This has been accomplished by projecting a plane of light and viewing the plane with a TV camera. Any surface intersecting the light plane reflects light along the line of intersection. Unless the surface is at an angle that prevents the reflected light from reaching the camera, an image of the line of intersection is obtained within the camera. Based on knowledge of the angle of light projection, distance from camera to projector and angle of the light received from the reflection, the distance from the camera/projector to the surface may be computed. This has the limitation of only providing measurements along the line of intersection which may not be adequate for an application requiring measurements over an area of the surface.
The measurement sensor formed by the camera and projector can be translated linearly by mechanical means to effect a scan of the surface. As the line of intersection scans the surface, it sweeps out an area on the surface over which 3-D measurements may be obtained. Although this is an effective way of obtaining data over a surface area, it is often undesirable to employ a translation table for reasons of cost, size, weight and complexity.