Uncertainty Estimation for Laser Triangulation Height Measurement

According to the Guide to the Expression of Uncertainty in Measurement, measurement uncertainty in quality control is especially important, as the measured value determines either the acceptance or rejection of a product. As the coordinate measuring machines are not capable of 100% dimensional quality control, the use of optical methods is growing. The problem here is still the lack of methods for metrological verification. The available regulations and norms are not directly applicable for all optical measurement principles. One example is the laser triangulation method. It has been used in the in-process production control in height measurement (1D), profile reconstruction (2D) or complete 3D scanning for over 30 years. This paperwork presents proposals of the procedure of measurements uncertainty evaluation for laser triangulation method. This method is designed for a semi-automatic determination of measure of the accuracy of shape reconstruction on the technical level and for a specific sensor. The process of the measurement in case of the laser triangulation method was divided into four sub-processes. The uncertainty for each of them can be estimated separately. Thanks to the presented method, the process of the triangulation system accuracy evaluation is remarkably quicker, in comparison with the typical multiple measurement with the use of reference objects. The correctness of the procedure was verified by the comparative research, which was based on the method of multiple height measurement of the set of block gauges.