Portable monocular light pen vision measurement system.

Abstract

This paper introduces a portable monocular vision measurement system that is suitable for measuring complex object surfaces or hidden features. The system mainly consists of a light pen, a camera, and a portable computer. First, without any control point, a camera calibration method based on the bundle adjustment is developed. This method can also be applied to calculate the positions of the feature points on the light pen. Second, we calibrate the probe tip center, since the position of the replaceable stylus is uncertain. Last, by taking images of the light pen when the stylus contacts the object's surface, we get the measured point's position. This measuring system is portable, efficient, and high-precision. Experiments show that in a 100 mm×200 mm field, the position errors of 66 points are less than 30μm.