An affine invariant weighted approach for estimating parameters under affine distortions

In this paper, an affine invariant weighted method is proposed to estimate affine transformation parameters. Affine covariant images are constructed from the original image by assigning an affine invariant weight to each point in the image. Based on the first order moment of these affine covariant images, a system of linear equations is constructed to estimate the affine transformation parameters. The affine covariant images are derived in polar coordinate system, and weights of points on the same radial direction can be calculated together. In compare with the cross-weighted moment method, the proposed method yields a smaller computation burden. Experimental results also show that the proposed method can be used for the recovery of affine transformation parameters by a proper selection of parameters.