Contactless Fingerprint Processing

Hi!

I’ve been trying to follow these two research papers, Priesnitz et al, and Rathgeb et al to implement and learn about contactless fingerprint capture, but I’ve reached a wall when it comes to processing the cropped and masked fingers

Specifically replicating Figure 5 in the first paper, or Figure 4 in the second. I successfully detect fingers and crop them, then separate them from the background, but it all falls apart when it comes to processing the greyscale image created afterwards (attached some cropped fingers for reference).

How could I create something similar?

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