Error Analysis of a Three-Dimensional GTA Weld Pool Surface Measurement System

Measurement of weld pool surface is an important research area in the welding community. In recent years, many vision-based approaches have been proposed that have achieved certain successes in this area. However, the accuracy of the measurement results in these systems deserves further consideration since the shape information of small weld pool surface may be used to validate welding models and control the process. In this paper, specific error analysis is given for our early proposed three-dimensional gas tungsten arc (GTA) weld pool surface measurement system, which utilizes the specular reflection characteristic of pool surface to do the measurement. First, all the measurement procedures related to the system error were introduced. Then the included error sources in each procedure were analyzed. Last, experiments and simulations were conducted to estimate measurement system error and other errors quantitatively. Through error analysis, the accuracy of the proposed measurement system was validated and the main error source was identified. This work is not only useful to improve the accuracy of our measurement method, but also instructive for error analysis of the others.