Remove radial overlap caused by sting on grooves

Previously, tiny bumps on groove edges could result in quite visible distortion in differentiated flattened groove radii. One source of error is in that edge detection could collect points around the stings so that wrong points are taken into account and made the signal longer than it really is. As in
http://kakyoism.webhop.net/~kakyo/0.report/37.flatten_sine/edge-fov1-r632-c368-i3-e2.png
The result of differentiation
http://kakyoism.webhop.net/~kakyo/0.report/37.flatten_sine/undudiff_radius_arc-fov632-368-3-2-fov631-369-4-2.png

These wrong points overlap in azimuth with the valid edge points. A simple treatment is then applied to the same image to remove the overlapped points: At each azimuth location of outer edge, reserve inner most edge point and for inner edge, outermost point. This way we ensure at teach azimuth, only one point is reserved. The result is immediately improved:
Raw flattened radius:
http://kakyoism.webhop.net/~kakyo/0.report/38.remove_sting/undu-fov632-368-3-2_631-369-4-2_radius_arc.png

Differentiated signal:
http://kakyoism.webhop.net/~kakyo/0.report/38.remove_sting/undu-fov632-368-3-2_631-369-4-2_diff.png

The source FOV treated after sting-removal
http://kakyoism.webhop.net/~kakyo/0.report/38.remove_sting/edge-fov1-r632-c368-i3-e2.png

This method is probably useful only to small stings, with larger bumps as in the same image. More sophisticated filtering should be used. Under investigation.