1. A method to filter outliers in an image-aided motion-estimation system, the method comprising: selecting eight-image-points in a first image received from a moving imaging device at at least one processor; selecting eight-image-points in a second image that correspond to the selected eight-image-points in the first image at the at least one processor, the second image being received from the moving imaging device; scaling the selected image-points at the at least one processor so the components of the selected image-points are between two selected values on the order magnitude of 1; building an 8-by-9 matrix (A) from the scaled selected image-points at the at least one processor; determining a condition number for the 8-by-9 matrix at the at least one processor; and rejecting the 8-by-9 matrix built from the selected image-points when the determined condition number is greater than or equal to a condition-number threshold.