If we suppose that every fingerprint is made of concentric curves (ellipses or circles) - and I'm aware of the fact that not every fingerprint is - how can I find center of those concentric curves?

Let's take this "ideal" fingerprint and try to find out its center ...

My approaches were to try:

• Find the spectrum through columns/rows of the image and try to find columns/rows that maximize particular band of the spectrum. I thought that column going through the center would have most regular pattern of changing amplitudes - therefore, most recognizible harmonic.
• My second approach was to try to count the changes of black-and-white also through the columns and rows, and to maximize that amount among rows and columns also.

While these methods work to the some extant, with some additional filtering, they fail, when fingerprint is "not ideal as this one is". Can you think of any different approach? Are there standard ways to do it?