Spoof detection by ultrasonic subdermal probe

An ultrasonic sensor system, comprising:

• a substantially planar piezoelectric transmit layer;
• an ultrasonic receiver array having a plurality of receivers;
• a platen;
• and
• control electronics configured to:
• produce, via the transmit layer, an ultrasound plane wave traveling toward an object proximate the platen, the object having an outer surface and internal structures;
• detect, via the ultrasonic receiver, ultrasonic energy that has been reflected from the object;
• analyze the detected ultrasonic energy to provide an analysis result indicative of the outer surface and at least one of the internal structures;
• and
• indicate whether the object is part of a living being based, at least in part, on the analysis result.

One or more non-transitory, computer-readable storage media having instructions stored thereon for performing a method of indicating whether an object is part of a living being, the method comprising:

• with an ultrasonic sensor comprising a substantially planar piezoelectric transmit layer, an ultrasonic receiver array having a plurality of receivers, and a platen:
• producing, via the transmit layer, an ultrasound plane wave traveling toward an object proximate the platen, the object having an outer surface and internal structures;
• detecting, via the ultrasonic receiver, ultrasonic energy that has been reflected from the object;
• analyzing the detected ultrasonic energy to provide an analysis result indicative of the outer surface and at least one of the internal structures;
• indicating whether the object is part of a living being based, at least in part, on the analysis result.