Bundle adjustment in industrial photogrammetry

Abstract Two ways of determining initial values for bundle adjustment in industrial photogrametry are first explained. One approach is based on solving the 11 parameters of the linear relation between photo and object space coordinates. Those parameters are related to the nine inner and outer orientation elements and two additional parameters. Six control points are needed per photo, or fewer if linear constraints for partly known orientation are added. Another approach is a closed solution for space resection from four control points, or fewer if outer orientation is partly known. It is based on solving the distances between camera station and control points from second degree equations by a search procedure. The bundle adjustment is performed iteratively: Orientation of photos, intersection of new points, repeated orientation, etc. The method allows for additional parameters and additional constraints for given spatial data, e.g. distances. Lastly, experiences with photogrammetry applied in shipbuilding are given.