Research On Motion Parameters Measurement System Of Golf Ball

The initial motion parameters measurement system of golf ball is an important part of the golf simulator. And it is required to have the characteristics of high accuracy and instantaneity. In the aspect of motion parameters measurement, radar sensor has the highest precision. But in some cases, the radar sensor has the problems that can’t detect the golf ball which has a low speed, or returns a wrong result when disturbed by other things. To solve these problems, a monocular vision system and a multi-sensor fusion system which contains a monocular vision sensor and a radar sensor are proposed. The purpose is improving the measurement system. The main work is as follows.First, this paper studies the camera calibration technique, the measurement model and the pose measurement theory of monocular system. A planar target is used to calibrate the camera and get the camera intrinsic parameters. Considering the characteristics of the golf ball and the requirements of calculating translation and rotation, the method based on the feature points target is chosen to measure the golf ball’s pose, which can be used to calculate motion parameters.Secondly, a spherical marker is designed which can meet the requirements of pose measurement. The design references to the criterion of artificial markers, and considers the characteristics of golf ball and its imaging. This paper also studies the method of target detection and feature extraction. The coordinates of feature points in the target coordinate, which can be obtained by the method, can provide the information for pose measurement.Finally, this paper studies the method of pose measurement and motion parameters calculation based on4points. The P4P theory is used to measure the golf ball’s pose. And the motion parameters, including the vectors of translational velocity and rotating angular velocity, can be calculated from the pose at different moments. Then a monocular vision system is built to measure the pose and motion parameters. Besides, based on the studies of multi-sensor data fusion, a multi-sensor system contains a monocular vision sensor and a radar sensor is proposed. And the process of decision-making layer fusion is completed. Then adopt a method of simulation to verify the performance of system. According to analyses of the results, the experiments indicate that the method based on the feature points target and the spherical marker designed in this paper can meet the requirements of the measurement. And the multi-sensor fusion system can improve the reliability of the measurement system.