A CRITERION OF RADIAL DISTORTION ON STRUCTURE FROM MOTION WITH CONSUMER-GRADE CAMERAS

Abstract

Images from consumer-grade cameras typically contain significant radial distortions, resulting in less accurate photogrammetry results generated using Structure from Motion (SfM). It is prone to reconstruct inaccurate scene points, becoming the so-called doming effect. The main reason is that in bundle adjustment, the last step of SfM, radial distortion is insufficiently estimated even though self-calibrating bundle adjustment was carried out. This paper designed a criterion to measure the radial distortion before SfM calculation, called Criterion on Radial Distortion (CRD). Firstly, the feature points were extracted and matched on the image; then, the image was divided into circular blocks, and the fundamental matrices were estimated by the matching points in different ring sub-blocks; finally, the difference between these fundamental matrices was used to reflect the radial distortion. Experiments on simulation data show that CRD can accurately reflect the radial distortion, which verifies its validity. Using actual UAV image data to conduct SfM experiments, CRD is consistent with the self-calibration results of Agisoft Metashape. After evaluating the accuracy of the elevation of scene points, it verifies its necessity for SfM.