That paper has absolutely nothing to do with generating keys directly from an image of a finger. They are discussing the lower bounds on how small a fingerprint

That paper has absolutely nothing to do with generating keys directly from an image of a finger. They are discussing the lower bounds on how small a fingerprint sensor can get. It doesn’t seem like you read my reply at all. It’s not a question of raw entropy from the sensor, which is what the paper is discussing. It’s an issue of repeatability.