Robust model-based tracking considering changes in the measurable DoF of the target object

Model based tracking approaches estimate the pose of the object by minimizing the re-projection error. However, when the object has some ambiguity, for instance, rotation invariance, the 3D pose cannot be correctly estimated. This paper proposes a novel method to allow continuous tracking even when the Degrees of Freedom (DoF) of the target object changes, being able to recover one missing DoF. Pose ambiguity test and recovery of the 3D pose by null space search were added into a general model-based tracking algorithm. Experiments were conducted in a synthetic and in the real world environment to validate the proposed method.