Currently, the viability of infrared (IR) as an accurate
means of measuring distance depends on extensive
prior know ledge of the surface. More speci-
cal ly, the manner in which a surface scatters, re
ects,
and absorbs infrared energy is needed to interpret the
sensor output as a distance measure. In order to use
IR in an unknown environment, one must determine
the surface properties during robot operation. This
paper details a method of determining the properties
of a surface, vis-a-vis infrared re
ectance, and subsequently
calculating the distance to the surface and
the relative orientation of the surface using previously
acquired sensory data. We present examples of IR distance
measures for various surfaces using known environments
as wel l as examples where the prior know ledge
has been acquired using sonar sensing. Our results
demonstrate that infrared sensors can provide accurate
range measurements when used in conjunction
with other sensing modalities to t model parameters
during robot operation (i.e. in real-time).