Research For Stereoscopic Vision System Using Light-Pen

According to the demand for the measurement of middle-size and small-size accessories during the developing process of modern measurement systems, and taking the camera, line structured laser, light-pen and etc as carriers, the dissertation studies on the working elements, transforming model and system calibration of the stereoscopic vision measurement system using light-pen deeply theoretically and practically, trying to bring forward a creative method on calibration and measured dots transformation, and prove it through hardware designing and software programming. At last, through the measurement for real objects and the analysis for the errors, it's proved the precision of this theory. The main and creative work in the dissertation consists of the following aspects:1. Using the RAC calibration method, and combining the analysis of the system transformation model, this paper built up the mathematical model of the CCD camera and compensated aberration error, and finished the calibration of camera.2. The barycenter method is used to get LED point facula's center. In order to advance the accuracy of point facula's center, certain threshold is used during calculation process to eliminate irrespective background value and the lens'aberration coefficient is used to compensated aberration error.3. Determine the number and distribution of LED on the light-pen. Take into account the size of camera field, image clarity and constraint relation of the point source, the measuring system designs of a suitable size of light-pen.4. Determine the 3D coordinates of LED's center. The stereoscopic matching principle is used to calculate the 3D coordinates of point source's center.5. Determine the 3D coordinates of measuring point. Using the 3D coordinates of LED's center, the distances between point source and penpoint and Least-squares method to calculate the 3D coordinates of measuring point.The stereoscopic vision measurement system using light-pen is not only making it breaking away from the limit of the outer drive set, but also improving the efficiency of system. At the same time this system is able to meet the requirements of high accuracy, and break away from the shackles of precision measuring instruments. Its advantages are measuring conveniently and portable, low cost, higher precision and high practical value.The innovation of this paper is advancing the 3D transformation model of the stereoscopic vision measuring system and using stereoscopic matching principle to get the 3D coordinates of characteristic point.