Apparatus for capturing a high quality image of a moist finger

Abstract

An apparatus for capturing the image of a wet/moist fingerprint. The apparatus includes: a prism having an imaging plane on which a finger having valleys and ridges is place, a bottom plane parallel to the imaging plane and a reflective plane intercepting the imaging plane and intercepting the bottom plane at an angle α; a light source for generating a light with an incident angle of approximately 0° with respect to a surface normal of the imaging plane; and a lens for capturing light reflected from the reflective plane. The apparatus further includes an image sensor for generating an image of the valleys and ridges of the finger, wherein the reflective plane is arranged in such a way to meet the equation of α>45 +(arc sin (n1/n2))/2, where n1 is a refraction index of medium filled between the valleys of the finger and the imaging plane, and n2 is refraction index of the prism.

Dependencies are inferred from the claim text.