On the Quality of Automatic Relative Orientation Procedures

This paper presents an empirical investigation into the quality of automatic relative orientation procedures. The results of an in-house developed automatic orientation software called AURELO (Läbe and Förstner, 2006) are evaluated. For this evaluation a recently proposed consistency measure for two sets of orientation parameters (Dickscheid et al., 2008) and the ratio of two covariances matrices is used. Thus we evaluate the consistency of bundle block adjustments and the precision level achievable. We use different sets of orientation results related to the same set of images but computed under differing conditions. As reference datasets results on a much higher image resolution and ground truth data from artificial images rendered with computer graphics software are used. Six different effects are analysed: varying results due to random procedures in AURELO, computations on different image pyramid levels and with or without points with only two or three observations, the effect of replacing the used SIFT operator with an approximation of SIFT features, called SURF, repetitive patterns in the scene and remaining non-linear distortions. These experiments show under which conditions the bundle adjustment results reflect the true errors and thus give valuable hints for the use of automatic relative orientation procedures and possible improvements of the software.