Locating of objects with discontinuities, boundaries and intersections using a compact ultrasonic 3D sensor

High resolution ToF measurements from multiple ultrasonic transmitter/receiver pairs allow determination of distance and bearing of reflectors. By combining methods for solving the echo correspondence problem, in case of multiple reflectors, and avoiding outliers, typically occurring on object discontinuities, a high quality map of 3D reflection points is obtained. This information is suitable for 3D scene analysis making it possible to determine location, orientation and parameters of planes, cylinders and edges. The presented sensor herein is low in cost, compact in size, can operate under real-time constrains and is suitable for a wide range of applications. Experimental verification was performed in an office room with multiple reflectors. Two planes are in close proximity showing the performance of solving the echo correspondence problem and the reduction of outliers. Determination of the orientation of a cylinder and its parameters in 3D show the high accuracy of the proposed system.