Profilometry using optical edge projection

Abstract

A novel optical edge projection method to measure the profile of an object is proposed. It can be applied to some special field for example to measure a profile of a specimen with a black and soft surface. A structured black-and-white light edge is projected onto an object surface and the distorted optical edge shadow image is captured by a CCD camera. The border line of the optical edge shadow is extracted and compared with a reference line, the distortion modulated by the height of the object surface is then obtained. By calculating the height, and scanning the optical edge shadow along the object, the height information obtained from a series of images can be determined. Combining the border line in these images, the profile of the object can be measured.