Small Body Exploration using Visual Methods Jean-Yves Bouguet(1), Andrew Edie Johnson(2) and Pietro Perona(1) (1) Department of Electrical Engineering California Institute of Technology 136-93, Pasadena, CA, 91125 (2) Jet Propulsion Laboratory

ABSTRACT:

We are developing techniques for building complete 3D models of small moving bodies from monocular visual input. The task consists of estimating the body motion as well as its three-dimensional shape using only an image sequence acquired by a single camera.

MOTIVATION & AIMS:

The purpose of this project is to build a system that enables accurate and autonomous position estimation near small bodies (such as comets or asteroids) using imaging sensors. The system consists of two onboard capabilities: local feature tracking for continuous estimates of the spacecraft motion, and landmark recognition and tracking for global position estimation. These capabilities must work during orbit and descent phases of missions and should be general enough to handle variations among small bodies including asteroids and comet nuclei, as well as potential change in lighting conditions (old project page).

RESEARCH:

We are experimenting different algorithms for motion and structure estimation from visual input (known as Structure-From-Motion algorithms in the vision community). This page regroups experimental results achieved on several sequences: two orbital sequences, and one descent sequence. It includes: feature tracking results, 3D motion and trajectory estimations, and 3D structure reconstructions (with recovered 3D meshes). The original sequences, together with the calibration data are available upon request to the authors.

The two orbital sequences were acquired using a turn table, and by rotating a rock by 2 degress between two consecutive images. For the first sequence, a large field of view lens was used (approx. 40 degrees FOV). The second sequence was acquired using a TV-photo lens was used (approx. 10-15 degrees FOV) making the overall reconstruction more challenging. The final presented experiment is a descent sequence, acquired with the same TV-photo lens. These sequences are simulating orbital and descent motions of an spacecraft near a comet.

ACHIEVEMENTS

We have demonstrated the applicability of automatically reconstructing accurate 3D models of small moving bodies only using a monocular sequence of images. The outcome is a dense 3D map of the body that can be further used for positioning purposes. The next step of the project consists of building a landmark recognition system that would enable a spacecraft to estimate its full 3D position with respect to the body at any phase of the approach from images, and the previously computed 3D model (during orbital motions).

Back to main page