Point Triangulation
Point triangulation sensors are the simplest of the family, collecting data at a single point on the object surface. In a point triangulation sensor, a light source, almost always a laser, projects a beam of light onto the surface to be measured. At the surface, the laser projects a spot of light at position A. At an angle to the laser beam, a lens is used to form an image or "picture" of this spot at an image plane at position A1. If the surface is farther away from the sensor, the spot on the surface is formed at position B, and the location of the imaged spot shifts to position B1. By determining the position of the imaged spot and calculating the angles involved, the distance from the sensor to the surface can be determined.
It is important to underst
and that triangulation involves imaging of the spot (essentially taking a picture of the spot on the surface), and not just collecting reflected light from the surface. It is the imaging of the laser spot on the surface that makes triangulation an elegant measuring tool. The imaging technique allows flexibility in the design of the triangulation sensor. For example, by altering the optical magnification of the imaging lens or the angle between the laser beam and the imaging axis, the sensor resolution and range can be changed.