Metric constraints
	Orthographic Camera • Rows of P are orthonormal: Weak Perspective Camera • Rows of P are orthogonal: Enforcing “Metric” Constraints • Compute A such that rows of M have these properties
	Trick (not in original Tomasi/Kanade paper, but in followup work) • Constraints are linear in AAT : • Solve for G first by writing equations for every Pi in M • Then G = AAT by SVD (since U = V)