Topology Matching of Branched Deformable Linear Objects

This paper presents a new method for correspondence estimation between a previously known topology of a branched deformable linear object and an image representation from a 3D stereo camera. Although frequently encountered in production, robotic deformable linear object manipulation still lacks reliable sensor feedback. Especially for branched deformable linear objects, such as wire harnesses, correspondence estimation is very challenging. Due to their flexible nature, they have an infinite-dimensional configuration space, such that visual appearances of the same object can vary strongly. Knowing the correspondence is vital for various applications, e.g., estimating valid grasping positions for robotic wire routing or augmented reality support for workers. Therefore, this paper presents a method for matching the topology of a branched deformable linear object to camera sensor data. Asymmetries in the wire harness design reduce the solution space by comparing the known topology of a model to the topology extracted from sensor data. The problem of finding the most likely solution to the matching problem requires features extracted from camera images. These features are used to construct a graph-based topology representation, which can then be matched to a graph-based topology representation of the known branched deformable linear object. The presented method is evaluated using multiple different non-overlapping configurations of a wire harness, showing the effectiveness of a graph-based segment matching approach.