US Patent 9879993 Enhanced bundle adjustment techniques

Novel tools and techniques that can be used to enhance the effectiveness of photogrammetric tools, such as bundle adjustment. One set of techniques can include a photo-observable backsight operation, in which a position of target point can be observed non-photographically, and this observed position can be used to constrain a pixel coordinate location of the same target point in a bundle adjustment operation. Using another technique, a photo-observable check shot operation, the observed position of another target point can be used to verify the validity of a bundle adjustment calculation. Such techniques can be used together or separately.