Described examples include an integrated circuit having a point identifier configured to receive a stream of input frames and to identify point pairs on objects in the input frames. A ground plane converter transposes a position of the point pairs to a ground plane, the ground plane having a fixed relationship in at least one dimension relative to a source of the input frames. A motion estimator estimates a motion of the source of the input frames by comparing a plurality of point pairs between at least two input frames as transposed to the ground plane, in which the motion estimator compares a motion estimate determined by the plurality of point pairs and determines a refined motion estimate based on the plurality of point pairs excluding outliers from the plurality of point pairs.