  Majority of the existing robot navigation systems, which facilitate the use
of laser range finders, sonar sensors or artificial landmarks, has the ability
to locate itself in an unknown environment and then build a map of the
corresponding environment. Stereo vision, while still being a rapidly
developing technique in the field of autonomous mobile robots, are currently
less preferable due to its high implementation cost. This paper aims at
describing an experimental approach for the building of a stereo vision system
that helps the robots to avoid obstacles and navigate through indoor
environments and at the same time remaining very much cost effective. This
paper discusses the fusion techniques of stereo vision and ultrasound sensors
which helps in the successful navigation through different types of complex
environments. The data from the sensor enables the robot to create the two
dimensional topological map of unknown environments and stereo vision systems
models the three dimension model of the same environment.
