Scanning device using high-resolution moisture discriminating optics

A fingerprint system, comprising:

• a platen comprising a light-reflecting surface;
• a light source configured to emit light rays to illuminate a finger placed in proximity to the light-reflecting surface of the platen;
• a sensor configured to capture image data of the finger in proximity to the light-reflecting surface of the platen;
• wherein the sensor and the platen are positioned relative to one another so that the sensor detects light propagating from the light-reflecting surface at an angle relative to a surface normal of the platen, wherein the angle is greater than a critical angle corresponding to an interface of the light-reflecting surface and water, and less than the critical angle corresponding to an interface of the light-reflecting surface and the finger being imaged by one or more hardware processors;
• and
• one or more non-transitory machine-readable storage media encoded with instructions that, when executed by the one or more hardware processors, cause the fingerprint scanner system to perform operations comprising:
• detecting multiple pores in the finger based on the image data of the finger in proximity to the light-reflecting surface of the platen.