Presented to the Robotics Institute
on March 15, 1996
Robot Evidence Grids
The evidence grid representation was formulated at the CMU Mobile
Robot Laboratory in 1983 to turn wide angle range measurements from
cheap mobile robot-mounted sonar sensors into detailed spatial maps.
It accumulates diffuse evidence about the occupancy of a grid of small
volumes of nearby space from individual sensor readings into
increasingly confident and detailed maps of a robot's surroundings. It
worked surprisingly well in first implementation for sonar navigation
in cluttered rooms. In the past decade its use has been extended to
range measurements from stereoscopic vision and other sensors, sonar
in very difficult specular environments, and other contexts. The most
dramatic extension yet, from 2D grid maps with thousands of cells to
3D grids with millions, is underway.
This talk presents the mathematical and probabilistic framework we now
use for evidence grids. It gives the history of the grid
representation, and its relation to other spatial modeling
approaches. It discusses earlier formulations and their limitations,
and mentions several extensions. Finally, a list of open issues and
research topics is presented.
Martin C. Martin