Automation in Mars Landing-site Mapping and Rover Localization

Our project aims to automate Mars mapping and localization using robotic stereo and descent imagery. Stereo vision is a wellstudied domain. However, most efforts aim only at a general scene; little work has been done toward a natural, extraterrestrial environment through consideration of its special geometry and features. Our methodology utilized the properties of piece-wise continuity of natural scene and monotonously decreasing parallax between horizontal-looking stereo cameras. In outline, our automation process for processing robotic stereo imagery is: 1) interest points are extracted as features and matched between intraand inter-stereo images, 2) tie points selection, 3) images with various illumination are balanced through use of tie points, 4) DEMs interpolation from 3-D interest points using Kriging and TIN, 5) orthophotos generation with DEM, and 6) landmarks (i.e. rocks) are extracted and occlusions are marked. Then, with the help of orthophotos, landmarks from different locations can be identified. Finally, robot localization is accomplished through use of rigid transformation and bundle adjustment of matched landmarks. For descent imagery, lower-level images are resampled and registered to higher-level images. Elevation is then estimated from multiple observations. This methodology has been used in the NASA 2003 Mars Exploration Rover Mission (MER) for precise robot navigation and mapping in support of the MER 2003 science and engineering team objectives.