In a method for determining touch applied to an electronic device, ultrasonic signals are emitted from an ultrasonic sensor. A plurality of reflected ultrasonic signals from a finger interacting with the ultrasonic sensor is captured. A first data based at least in part on a first reflected ultrasonic signal of the plurality of reflected ultrasonic signals is compared with a second data based at least in part on a second reflected ultrasonic signal of the plurality of reflected ultrasonic signals. A signal change due to a deformation of the finger during a touch interaction with the ultrasonic sensor is determined based on differences between the first data and the second data. A touch applied by the finger to the electronic device is determined based at least in part on the signal change due to the deformation.