Determining touch applied to an ultrasonic sensor

An electronic device comprising:

• an ultrasonic sensor for emitting ultrasonic signals and capturing reflected ultrasonic signals from a finger interacting with the ultrasonic sensor;
• a processor capable of determining touch applied to the electronic device by the finger, wherein the processor is operable to:
• compare a first data based at least in part on a first reflected ultrasonic signal of the reflected ultrasonic signals with a second data based at least in part on a second reflected ultrasonic signal of the reflected ultrasonic signals;
• determine a signal change due to a change in a feature of the finger during a touch interaction with the ultrasonic sensor based on differences between the first data based at least in part on the first reflected ultrasonic signal and the second data at least in part based on the second reflected ultrasonic signal;
• and
• determine a touch applied by the finger to the electronic device based at least in part on the signal change due to the change in the feature of the finger.

A sensor processing unit comprising:

• an ultrasonic sensor for emitting ultrasonic signals and capturing reflected ultrasonic signals from a finger interacting with the ultrasonic sensor;
• a sensor processor capable of determining touch applied to an electronic device comprising the ultrasonic sensor by the finger, wherein the sensor processor is operable to:
• compare a first data based at least in part on a first reflected ultrasonic signal of the reflected ultrasonic signals with a second data based at least in part on a second reflected ultrasonic signal of the reflected ultrasonic signals;
• determine a signal change due to a change in a feature of the finger during a touch interaction with the ultrasonic sensor based on differences between the first data based at least in part on the first reflected ultrasonic signal and the second data at least in part based on the second reflected ultrasonic signal;
• and
• determine a touch applied by the finger to the electronic device based at least in part on the signal change due to the change in the feature of the finger.