A vision-based method for the circle pose determination with a direct geometric interpretation

A novel vision-based method for the circle pose determination is addressed. This method is based on two particular projected chords of a circle image. The first one is the projection of a circle chord which subtends the largest apex angle of the viewing cone for the circle image and the second one is the projection of a circle diameter whose back-projection plane bisects the above largest apex angle. This method is conceptually simple, since the circle center is the center point of the diameter chord and the circle orientation is given by the cross product of these two (directed) chords. We present theorems on the geometry of both the viewing cone and a re-projected circle image which are essential to the pose determination. We then give a pose determination method which is applicable under all viewing conditions. Experimental results illustrate the good performance of the method, when compared with other existing methods.