A Laser and Vision-Based Microspatial Angle Measurement Technique for Datum Transformation

The precise microspatial angle measurement is of great importance for error compensation in datum transformation by laser beam. The commonly used angle measurement methods have problems, such as complex systems, difficult processing of key equipment, and difficulty in optical path installation or adjustment, so these methods are not the best choice to compensate error in datum transformation by laser beam. This article presents a microspatial angle measurement method and device for datum transformation, a fixed cross laser beam was used as optical measurement datum, and a beam splitter was used to split the cross laser beam. Based on the author’s previous work, the position and angle information of the cross laser pattern in two image acquisition systems were extracted, and the proposed method realizes microspatial angle measurement based on the extraction results and the proposed measuring device. With the light filtering dark chamber, environmental stray light interference could be effectively reduced, improving environmental adaptability of the system; with error compensation experiments, the law of systematic error was explored, improving system measurement accuracy. The experimental results show that the uncertainty of angle measurement meets requirements. Based on the camera of 14 fps, as well as the cross-laser-pattern image processing speed, its measurement frequency could theoretically reach 10 Hz. The proposed measurement system has a wide application, and it not only provides a new method and idea for error compensation in datum transformation but also can be applied to other fields that require microspatial angle measurement.