Design of high-resolution thin line structured light measurement system

To achieve high-precision 3D measurement of surface profile of the object, a telecentric optical path measurement system with large field of view (FOV), object distance and measuring range was proposed. The composition of the system and the principle of optical triangulation were introduced, the construction of the optical path with the angle of 45 ° between the projection and double optical path and the normal line of the measured surface could reduce the requirement of depth of field of the imaging objective lens for large depth measurement range. The theoretical model of system depth calibration was established, and the theoretical value of CCD unit pixel depth was 0.554 4 μm. The magnification, numerical apertures and other optical parameters were calculated and the optical path was constructed. The resolution, measuring range, minimum width of light stripe and edge quality of the system were analyzed by experiments. The experimental results show that the longest projection stripe is 2 mm, the minimum line width is 8.96 μm, and the stripe edge is clear and smooth. The imaging distortion of the system is small, and the optical resolution of 1.62 µm and the depth pixel resolution of 0.54 µm can be achieved. The object distance is 65 mm, the depth measurement range is no less than 140 µm. The system has good measurement performances.