Improved range estimation using simple infrared sensors without prior knowledge of surface characteristics

Abstract

This thesis describes a new method for range estimation using low-cost infrared sensors. The intensity data acquired with infrared sensors depends highly on the surface properties and the con guration of the sensors with respect to the surface. Therefore, in many related studies, either the properties of the surface are determined rst or certain assumptions about the surface are made in order to estimate the distance and the orientation of the surface relative to the sensors. We propose a novel method for position estimation of surfaces with infrared sensors without the need to determine the surface properties rst. The method is relatively independent of the type of surface encountered since it is based on searching the maximum value of the intensity rather than using absolute intensity values for a given surface which would depend on the surface type. The method is veri ed experimentally with planar surfaces of di erent surface properties. An intelligent feature of our system is that its operating range is made adaptive based on the intensity of the detected signal. Three di erent ways of processing the intensity signals are considered for range estimation. The overall absolute mean error in the range estimates has been calculated as 0.15 cm in the range from 10 to 50 cm. The cases where the azimuth and elevation angles are nonzero are considered as well. The results obtained demonstrate that infrared sensors can be used for localization to an unexpectedly high accuracy without prior knowledge of the surface characteristics.