Occlusion-aware multi-view reconstruction of articulated objects for manipulation

• Use of the Procrustes-Lo-RANSAC (PLR) algorithm to perform 3D reconstruction of articulated objects.
• A purely geometric approach recovers the axes’ location, orientation, and type (revolute or prismatic).
• The resulting 3D model is occlusion-aware, meaning that parts not visible in the current view are included.

We present an algorithm called Procrustes-Lo-RANSAC (PLR) to recover complete 3D models of articulated objects. Structure-from-motion techniques are used to capture 3D point cloud models of an object in two different configurations. Procrustes analysis, combined with a locally optimized RANSAC sampling strategy, facilitates a straightforward geometric approach to recovering the joint axes, as well as classifying them automatically as either revolute or prismatic. With the resulting articulated model, a robotic system is then able to manipulate the object along its joint axes at a specified grasp point in order to exercise its degrees of freedom. Because the models capture all sides of the object, they are occlusion-aware, meaning that the robot has knowledge of parts of the object that are not visible in the current view. Our algorithm does not require prior knowledge of the object, nor does it make any assumptions about the planarity of the object or scene. Experiments with a PUMA 500 robotic arm demonstrate the effectiveness of the approach on a variety of real-world objects containing both revolute and prismatic joints.