Fusion of real and logical sensors derived from range and intensity images

An experiment in fusion of real and logical sensors derived from range and intensity images is described. The real sensor used is an active triangulation laser range finder that has programmable speed and region-of-interest scanning and produces range and intensity return images. The logical sensors, which provide intensity edges, jump edges, convex and concave fold edges, and surface curvature derived from these images, are discussed. Theoretical and experimental means of characterizing these sensors and building a satisfactory sensor model are described. The characterization is made both in terms of measurement accuracy and range dependency of the logical sensors on intensity of the returned laser light. The use of the sensor and its model for edge based segmentation is described and evaluated with several test images. Each of the categories of edges is independently detected using the sensor model. The decision based upon the different logical sensors is the result of fusion using dependency rules about the sensor interactions. The result is an edge map with labeled edges. A rule based approach to closing the gaps in this edge map is described and the final segmentation is obtained. It is shown that the fusion helps in finding and localizing correct edges, as well as removing spurious edges.