Research On Digital Method Of Measuring The Height Of Ocean Wave

According to the requirement of high accuracy and real time test in project, a visual measurement based on structured light for ocean wave height measurement is researched after illuminating the development overview in this field. Considering the specificity of wave image, key techniques in structured light visual inspection such as image feature extraction, vision sensing measurement and calibration is researched theoretically and practically, and then corresponding experimental demonstration work is designed and completed. Experiment results show that ocean wave height measuring method proposed in this paper is of advantages such as real time and reliable precision to meet measuring demands. The main content and innovation of this paper include:1. The research background and study situation is described briefly at home and abroad. After comparing with several programs used for wave height measuring in laboratory, a visual measurement based on structured light is proposed and some key techniques especially main problem as well as technical difficulties are illuminated.2. According to the analysis of optical properties and light stripe distribution of water surface, this paper proposes a quick method based on gray statistic to extract light strip center, which breakthroughs traditional ways based on line structural light extraction. Dynamic real-time monitoring shows that this method is feasible, easy to operate and suitable to extract water strip image in laboratory conditions.3. The vision measurement principle based on structured light and camera imaging model is discussed and analyzed in detail. And the wave height solution method based on collinearity equation model is built. This paper lists various types of camera calibration method and finally choose one method based on checkerboard. This approach could obtain both internal and external camera parameters with high precision, and is of advantages such as convenience, practice as well as without high precision calibration block.4. The traditional system calibration of structured light vision measurement technology is explained. An indirect calibration method based on cross line laser is researched and a site-specific calibration step is given. By evaluating the light plane calibration parameters, the results could achieve reliable and satisfactory accuracy.5. According to wave theory, the digital testing platform based on swing-type wave is built and the OpenGL based 3D visualization software platform is designed. In order to verify the measuring method and system calibration accuracy, the experiments of the system calibration precision, the static water test precision and the dynamic testing of wave height on the digital test experiment platform is finished. Experimental data and results show that the method based on structured light for wave height measurement is feasible and well real-time, which could achieve wave height test in laboratory conditions with the accuracy better than 1mm.