Removing background from fingerprint images

how to remove background from fingerprint image without loosing fingerprint information. output image should be grayscale image not binary. please help.

Answer 1

[Image Analyst]

Try my background correction demo, attached. It uses John D'Errico's polyfitn to fit the background to a 2D polynomial. Then I divide the image by it.

Alternatively you can look for fingerprint articles here http://iris.usc.edu/Vision-Notes/bibliography/contentspeople.html#Face%20Recognition,%20Detection,%20Tracking,%20Gesture%20Recognition,%20Fingerprints,%20Biometrics to see how researchers in the field are doing it.