Modeling and calibration of a structured-light-sensor-based five-axis scanning system

With the development of industry structured-light sensors have been widely applied in reverse engineering and quality control. Due to the incapability of changing their orientations continuously in response to the surface fluctuation of a part to be measured, they have met some challenges on measuring complex structured parts. In this paper a five-axis scanning system integrated with a CMM, a structured-light sensor and a PHI OM rotary head is proposed, which can index the sensor's orientation by the rotation of PH10M automatically. The system model is established to transform the 2D data got from the sensor into 3D data in world coordinate system. By measuring a fixed point (ball center) using the sensor at different orientations, some "conjugate pairs" are identified for solving the system model. A "conjugate pair" corresponds to the coordinate of the fixed point in 2D sensor coordinate system, a set of PH10M rotation angles, and the coordinate got from the CMM optical scales. To ensure that the fixed point can measured by the sensor, an algorithm for determining the position of the CMM scanning axis where the laser plane passes through the fixed point is put forward. Experiment study shows that the system model is correct and the calibration accuracy is high enough to gain accurate 3D measurement. (C) 2004 Elsevier Ltd. All rights reserved.