A high resolution 3-D surface profiling system

Abstract

An improved version of the structured sine wave illuminated three-dimensional vision system has been developed in order to obtain high depth resolution. Errors generated by local imperfections in the sine wave grating have been compensated for in order to achieve this resolution. The method uses a collimated laser beam for illumination of the surface. It is sinusoidally intensity modulated along a transverse direction by a grating. An image of the surface is recorded by a camera placed at an angle with respect to the incident laser beam. The depth change of the surface from pixel to pixel, measured by phase modulation of the sinusoidal intensity distribution. Test measurements made on several sample objects show that a depth resolution better than 0.05 mm is achievable.