Local Surface Reconstruction of Objects in Space

The increasing number of objects orbiting our planet necessitates the creation of sensing systems designed to determine the surface structure of such objects. One of the key challenges facing computer vision systems used in space is the presence of specular surfaces on most man-made orbital objects. Such surfaces present a challenge to conventional vision systems due to specular reflections, which may mask the true location of the object and hence lead to incorrect measurements. The incorporation of traditional highpowered illuminants, such as laser beams, in a space-based computer vision system can also be problematic since the instruments inside space structures may be sensitive to various forms of radiation. A properly designed computer vision system could assist in the repair and maintenance of delicate space equipment. This article describes the development of a fixed vision system which can recover the local surface structure of highly specular objects. The system utilizes a commercial trinocular stereo vision system and a low-power twodimensional illuminant. The local surface structure of an object is obtained by projecting coded light patterns onto the object. As space objects are neither fully specular nor fully diffuse, an algorithm has been developed which recovers local surface structure from both the specular and diffuse regions of an object.