The invention is related to methods and apparatus that use a visual sensor
and dead reckoning sensors to process Simultaneous Localization and
Mapping (SLAM). These techniques can be used in robot navigation.
Advantageously, such visual techniques can be used to autonomously
generate and update a map. Unlike with laser rangefinders, the visual
techniques are economically practical in a wide range of applications and
can be used in relatively dynamic environments, such as environments in
which people move. One embodiment further advantageously uses multiple
particles to maintain multiple hypotheses with respect to localization
and mapping. Further advantageously, one embodiment maintains the
particles in a relatively computationally-efficient manner, thereby
permitting the SLAM processes to be performed in software using
relatively inexpensive microprocessor-based computer systems.