Fully affine invariant matching algorithm based on nonlinear scale space for side scan sonar image

A fully affine invariant matching method for side scan sonar image is proposed in this paper. This method uses fully affine invariant features under nonlinear scale space built by nonlinear diffusion filter. We call the new Nonlinear Affine Inva-Riant feature NAIR feature, it makes full use of the advantage of affine invariant of ASIFT algorithm and feature distinctiveness in nonlinear scale space. It overcomes the problem of the failure of large view-changed side scan sonar image matching caused by the change of heading direction during sonar data acquisition and the anti-noise performance is enhanced through the nonlinear diffusion filter. The experimental results show that the proposed method has better anti-noise performance and higher accuracy compared with the state of art feature matching algorithms.