Solving the bas-relief ambiguity

Bas-relief ambiguity exists from two views in points correspondence. Solving this problem relies on either prior knowledge of the motion or further projection such as three views. It is shown in this paper that the unique solution exists from only one pair of correspondence with the prior knowledge of known rotation axis. The least square approach is derived to compute the rotation angle in the presence of noise. The advantage of such an approach is that no camera calibration is required. Further, we show that the least squares approach is statistically unbiased and produces stable results with noisy data