Bend tube spatial parameter measurement method based on multi-vision

Aiming at the problems that it is difficult to ensure the measurement precision and the measurement efficiency is low in the spatial parameter measurement of large size and complex bend tubes, a non-contact measurement method of bend tube spatial parameters based on multi-vision is presented. According to multi-vision principle, this method acquires the 3-D coordinates of the bend tube spatial central axis from different points of view adopting the matching method based on central axis, and calculates the bend tube external diameter from the edge lines. With 3-D modeling technology, the 3-D model of the measured bend tube is reconstructed. A bend tube spatial parameter measurement system with eight cameras was designed and built. The measurement experiment proves that the proposed method and measurement system can realize fast measurement of bend tube spatial parameters, and the measurement time can be controlled within 1 min. The measurement error of the central points on both sides is 0.25 mm, the measurement error of external diameter is 0.072 1 mm, and the measurement error of bending angle is 0.278°.