EXACT AND APPROXIMATE SOLUTIONS OF THE PERSPECTIVE-3-POINT PROBLEM

Model-based pose estimation techniques that match image and model triangles require large numbers of matching operations in real-world applications. We show that by using approximations to perspective, 2-D lookup tables can be built for each or the triangles of the models. An approximation called "weak perspective" has been applied previously to this problem; we consider two other perspective approximations: paraperspective and orthoperspective. These approximations produce lower errors for off-center image features than weak perspective.