| There comes in vision measurement fields a new technique called probe imaging vision coordinates measurement technique which is combined the technique of the conventional coordinates measurement and vision measurement. The 3D coordinates of the measured point can be got by analysing the images of probe which used to be the image of the points on the measured surface in this technique. The problem of vision measurement on the complex shape is not a difficult one because the measured object in vision measuremt is not the point of object surface but the probe. The 3D vision coordinates measurement system using Light Pen is proposed on the new technique. The structure of the system is simple. It includes a light pen, one or more CCD cameras and a computer. The system is easy to be operated. For example when the Light Pen touches the measured point, the CCD camera at once incepts the image position of the LEDs on the light pen and a monitor will show the 3D coordinates of the measured point after the computer's system disposal. The precision of measurement reaches to 0.1 mm in measuring space of 1m. The system can be set up dynamically, which satisfes the request of the real-time measurement.The main topics in this thesis are as follows:The traits of the conventional CMM and vision measurement were studied. The key technique of the portable 3D vision coordinates measurment system using light pen was analysed.The whole configuration design was improved. Based on the perspective view of three points, the system model was established and solved. A new camera calibration method using the CMM and the devices by hand was proposed.A digital subtract method was brought into the pick-up process of the characteristic points, and an ellipse curve fitting algorithm was applied to get the center of the characteristic points.The feasibility, stability and accuracy of this system were tested by experiments. Some further improvements were pointed out.
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