Proceedings Article | 30 April 2009
Weihong Zhang, Ping Zhuang, Les Elkins, Rick Simon, David Gore, Jeff Cogar, Kevin Hildebrand, Steve Crawford, Joe Fuller
KEYWORDS: Cameras, Clouds, Imaging systems, Stereoscopic cameras, Calibration, Navigation systems, Image processing, RGB color model, Convolution, Edge detection
Spatial Integrated System (SIS), Rockville, Maryland, in collaboration with NSWC Combatant Craft Division
(NSWCCD), is applying 3D imaging technology, artificial intelligence, sensor fusion, behaviors-based control,
and system integration to a prototype 40 foot, high performance Research and Development Unmanned Surface
Vehicle (USV). This paper focus on the developments of the stereo camera system in the USV navigation that
currently consists of two high-resolution cameras and will incorporate an array of cameras in the near future.
The objectives of the camera system are to re-construct 3D objects and detect them in the sea water surface.
The paper reviews two critical technological components, namely camera calibration and stereo matching. In
stereo matching, a comprehensive study is presented to compare the algorithmic performances resulted from
the various information sources (intensity, RGB values, Gaussian gradients and Gaussian Laplacians), patching
schemas (single windows, and multiple windows with same/different centers), and correlation metrics (convolution,
absolute difference, and histogram). To enhance system performance, a sub-pixel edge detection technique
has been introduced to address the precision requirement and a noise removal post-processing step added to
eliminate noisy points from the reconstructed 3D point clouds. Finally, experimental results are reported to
demonstrate the performance of the stereo camera system.
