Study On The Key Technologies Of Instrumentation Of 3D Visual Inspection

The three-dimensional visual inspection technologies in the world and three universal vision system schemes are exhaustively analyzed in the thesis based on the demands and applications of the technology through the development of the modern measurement technology. The research is mainly conducted to the key technologies of three-dimensional visual inspection, such as image feature extraction, vision sensor calibration and measurement, abiding by the instrumentation regulation of high precision, universality, uniformity, flexibility and practicality. Both theoretical and practical researches and discussions were taken, and some creative theories and means, as well as experimental validation were finished. The main work of the thesis is as follows:1. Introduction of the demands and application domains of three-dimensional visual inspection, the development of three-dimensional visual inspection technologies in the world. Analysis of three universal vision system schemes for dimension and surface visual inspection. Explanation of the common and key technologies, especially not have been solved exhaustively.2. A novel structure-uniform stereovision sensor for various three-dimensional feature inspection tasks, such as hole, edge, surface and so on, based on the active and passive visual inspection methods.3. Analysis of camera calibration methods in detail. The research on a universal camera calibration method with unknown camera initial parameters and planar pattern position, which estimate all the camera parameters including lens radial and tangential distortion coefficient with high precision.4. High-precision calibration solution of a structure-uniform stereovision sensor with free-position planar pattern. The uniform mathematical model was constructed. The solution was proven by experiments to be easy, flexible, with high precision.5. High-precision calibration solution of a structured light stripe vision sensor, which is suitable in flexible three-dimensional visual inspection system based on the industrial robot platform. The solution simplified the calibration set-up greatly, and was proven by experiments to be easy, flexible, with high precision.6. The research on the image feature extraction technology in the visual inspection. The auto-segmentation and sub pixel auto-location method of ellipse was presented. The high-precision light stripe location technology base on the Hessian matrix through exhaustive analysis of light stripe extraction algorithm was proposed and validated by experiment.7. Creation of the reparability method of stereovision sensor. The method was proven by experiment to be practical in the three-dimensional visual inspection system, which is sensitive to the light.8. Creation of the two-step hole inspection technology with structured light stripe vision sensor, and exhaustive analysis of measurement error. The method broke the traditional hole inspection method with stereovision sensor, and was proven by experiment to be valid.