A moment-based approach for deskewing rotationally symmetric shapes
The covariance matrix of a rotationally symmetric shape is a scalar identity matrix. We apply this property of covariance matrix to deskew the skewed shape of rotational symmetry. The parameters of the deskew transformation matrix are solved by letting the covariance matrix of the transformed shape be equal to a scalar identity matrix. Then, the rotationally symmetric shape can be recovered by the deskew transformation matrix. The method does not rely on continuous contours, since only second-order moments of the input shape are required to be computed. Experimental results are also presented.