Resolving ambiguities of self-calibration in turntable motion

A camera under general motions allows the fixed geometric entities: the absolute conic and the plane at infinity to be determined uniquely for self-calibration. For turntable motions, these two geometric entities cannot be determined, and will lead to ambiguities in 3D reconstruction. However, some fixed points and lines will arise as a result of turntable motions, and can be related to the calibration matrix. We have made two contributions for self-calibration under turntable motion. First, a detailed theoretical analysis of degeneracy is given, and the degrees of the resulting ambiguities are deduced. Second, from some constraints on the physical characteristics of the camera the ambiguities can be removed up to a single parameter family. Experiments on real turntable image sequences verified our findings which are used also to perform a 3D reconstruction