Binocular Robot Vision with Active Viewpoint for Sphere Measurement

A binocular robot vision system reconstructs 3D scenes from right and left images by using triangulation. However when using triangulation, the corresponding problems have to be resolved. To resolve the corresponding problems easily, authors have proposed a binocular robot vision system with an autonomously moving active viewpoint. By using this active viewpoint, the system constructs the correspondence between images of feature points of an object on the right and left images and calculates the spatial coordinates of the feature points. However the system cannot achieve correspondence between right and left images for smooth surface without feature points like corners. In this paper, we propose a method to extract feature points on a smooth surface virtually. To extract the feature points on the smooth surface of an object virtually, we use an active viewpoint of our system and vergence motion of the right and left cameras. In this system, the right and left cameras viewpoints are corresponded mechanically by the active viewpoint and vergence motion of both cameras. As the virtual feature point, a contact point between the smooth surface and tangential line from the epipole on the baseline of right and left cameras is extracted from the camera images. Because the right and left cameras viewpoints are fixed by the active viewpoint, the active viewpoint becomes the constraint for the extraction of the virtual feature points. The information of the virtual feature points on the smooth surface of an object is used for the calculation of the spatial coordinates of the object. The effect of the proposed method to extract the feature points virtually is shown experimentally by using a sphere as an object.