Stereo vision system for capture and removal of space debris

In order to enable the non-cooperative rendezvous, capture, and removal of large space debris, automatic recognition of the target is needed. Several technologies are currently available and stereo vision is one of the most suitable in the strict context of space missions, where low energy consumption is fundamental and sensors should be passive in order to avoid any possible damage to external objects as well as to the chaser satellite (e.g., scattered reflection of laser scanners may potentially be an issue). In this paper we are presenting a stereo vision system we set up in order to reconstruct the object model of space debris. Histogram equalization, executed by a programmable system-on-chip board equipped with a couple of cameras, and SIFT features extraction are the two fields of investigation. We identified the parameters that such a system have to deal with, and implemented a prototype solution tested in lab with debris mock up and actual satellite models. Results are demonstrating that fast image pre-processing is needed for having an acceptable recognition of object depth and shape. The proposed system can be integrated with other vision techniques to improve the comprehension of debris model allowing a fast evaluation of associated kinematics to select the most appropriate approach for capture.