Position and orientation measurement using monocular camera-ultrasonic sensor configuration mounted on robot

A method was proposed for measuring the position and orientation of objects using monocular CCD camera and a ultrasonic sensor. Firstly, in the image coordinate, the undistorted coordinates of the desired point on objects was obtained from one image captured by the CCD camera, from which the orientation of the projection vector (the line connecting the object point and its image) was obtained. Then, by moving the robot, let the z axis of the ultrasonic sensor coincide with the orientation of the projection vector; lastly, the length of the vector was measured using the ultrasonic sensor, and the point coordinates in the camera coordinate system were calculated. The mainly factors that affected the measurement accuracy were analyzed, the influence of mounting parameters of the ultrasonic sensor was discussed and simulations were given. The position and orientation of objects can be measured rapidly and accurately with low computation cost and the avoidance of the image watching in stereo vision.