A new static method of calibration for low-cost laser triangulation systems

Abstract

As a non-contact high-efficiency method, laser triangulation has long been studied by many scholars. Building such a system usually requires calibration where system parameters are found or amended to achieve the targeted precision. Traditional calibration methods require using either precise movement or high precision gauge object that are accompanied with extra manufacturing cost and auxiliary equipment/devices and hence increase the overall cost as well as prevent widespread applications, for instance, due to required environment conditions to be fulfilled. A new static method was, therefore, proposed to calibrate a system without need of a motion or a high precision gauge object to be deployed. The method relies on preparation of the data on a scalar compound target with a geometric estimator as quality indicator. Based on this method, three versions of a low-cost prototype were built, which achieved sub-millimeter precision. Although the precision is sufficient for a measurement often used manufacturing large panels, higher precision is achievable with additional work which is to be undertaken in the future. The proposed method makes tradeoff between precision and cost. This was followed by testing on the measurement of a small panel part as application-case study. The proven feasibility of the method proposed suggested potential of developing low-cost, inline industrial system (large or small) for inspecting sheet parts during manufacturing, especially panel component manufacturing, including that from metal sheets and composite materials.