A comparative study of five algorithms for processing ultrasonic arc maps

In this work, one newly proposed and four existing algorithms for processing ultrasonic arc maps are compared for map-building purposes. These algorithms are the directional maximum, Bayesian update, morphological processing, voting and thresholding, and arc-transversal median algorithm. The newly proposed method (directional maximum) has a basic consideration of the general direction of the mapped surface. Through the processing of arc maps, each method aims at overcoming the intrinsic angular uncertainty of ultrasonic sensors in map building, as well as eliminating noise and cross-talk related misreadings. The algorithms are implemented in computer simulations with two distinct motion-planning schemes for ground coverage, wall following and Voronoi diagram tracing. As success criteria of the methods, mean absolute difference with the actual map/profile, fill ratio, and computational cost in terms of CPU time are utilized. The directional maximum method performed superior to the existing algorithms in mean absolute error, was satisfactory in fill ratio and performed second best in processing times. The results indicate various trade-offs in the choice of algorithms for arc-map processing.