Study on reconstruction of marker point cloud in single camera photogrammetry

This study designs an algorithm to reconstruct the marker point cloud using a monocular camera. The specific processes can be described as: Firstly, a group of images containing only the coded marker and the reference ruler are used for selfcalibration; Secondly, another group of object images are reconstructed by the internal parameters of the camera; The processing algorithms of the two groups of images are similar, and the second group needs additional matching and reconstruction of noncoding points. When a large number of coding marks cannot be placed on the surface of the object to be measured, the observed value of adjustment is reduced. The experimental verification of industrial structural parts shows that the measurement error is 0.05 mm and the relative error is 0.02% in the measurement range of 5 m. Compared with the method using camera internal parameter as observation value adjustment, the accuracy is similar, the number of observations is reduced and it can be applied to most industrial measurement fields.