The value is initialized to a small value, e.g. . If the value obtained for reduces the error, the increment is accepted and is divided by 10 before the next iteration. On the other hand, if the error increases then is multiplied by 10 and the augmented normal equations are solved again, until an increment is obtained that reduces the error. This is bound to happen, since for a large the method approaches a steepest descent.

Marc Pollefeys 2002-11-22