I worked with a team to develop and maintain the software of a passive-light based 3D scanner, for unmanned boat navigation purpose. The scanner is composed of a pair of optical cameras, and the software is able to capture 3D shape of objects in the field of view. The software was originally written in C/C++ and then was modified by parallel computation coding technique, i.e. NVIDIA's CUDA, to achieve close to realtime 3D calculation. The scanner was then mounted on the boat, captured the scene in realtime, and planned its route according to the captured 3D scene.