Three-dimensional shape measurement system using optical spatial modulator and zoom camera

An automatic measurement system of three-dimensional shapes by a projection method with striped patterns from an optical spatial modulator has been developed. Patterns on the surface of the object were taken into a computer by a CCD camera, and the 3D cocordinate of the surface of the object was calculated according to a principle of a trigonometry measurement. This system has the following advantages. (1) It is possible to capture the surface topography without any contact. (2) The time required for the measurements is shorter than the light-section method. (3) The optical spatial modulator using a liquid crystal projector is possible to control the striped patterns accurately by the computer. (4) It is possible to measure precisely and to expand the measurement area using a zoom camera. In this study, we developed the method with using zooming of a CCD camera image. By using zooming of a CCD camera image, the measurement accuracy improved and the measurement range was expandable.