Laser illumination
Projecting a laser line or pattern onto an object and using a camera at a known angle to capture the result reveals displacement of the beam so that this can be measured to provide height information. In addition to points and lines many other patterns such as crosses, circles, squares, dot matrices, multiple lines, or grids can be used. These are created by means of diffractive optical elements (DOEs) which are based on the principle of light diffraction by small micro structures. Depending on the light pattern either triangulation, light section or a grid projection should be used.