Fingerprint sensor with force or pressure feedback

1. A method of controlling an apparatus that includes a fingerprint sensor system, the method comprising:

controlling, via a control system, the apparatus to provide a first prompt to place a digit on an outer surface of the apparatus in a fingerprint sensor system area;

determining, via the control system, a digit force or a digit pressure of the digit on the outer surface of the apparatus;

obtaining fingerprint image data;

determining an image quality metric corresponding to the fingerprint image data; and

controlling, via the control system, the apparatus to provide a second prompt corresponding to the digit force or the digit pressure, wherein the second prompt is based, at least in part, on the image quality metric.

2. The method of claim 1 , wherein providing the second prompt involves presenting a graphical user interface (GUI) on a display device of the apparatus.

3. The method of claim 2 , wherein the GUI indicates a current digit force or a current digit pressure.

4. The method of claim 3 , wherein the GUI indicates whether the current digit force or the current digit pressure is within an acceptable range.

5. The method of claim 3 , wherein the GUI indicates that the current digit force or the current digit pressure is not within an acceptable range and wherein the GUI includes a prompt to change the current digit force or the current digit pressure.

6. The method of claim 3 , wherein the GUI corresponds with a force calibration phase or a pressure calibration phase of a user enrollment process.

7. The method of claim 3 , wherein the GUI corresponds with a fingerprint capture phase of a user enrollment process.

8. The method of claim 3 , wherein the GUI corresponds with an authentication process.

9. The method of claim 1 , wherein providing the first prompt involves presenting a graphical user interface (GUI) on a display device of the apparatus.

10. The method of claim 9 , wherein the GUI corresponds to a user enrollment process.

11. The method of claim 9 , wherein the GUI indicates the fingerprint sensor system area.

12. The method of claim 9 , wherein the GUI corresponds to an authentication process.

13. The method of claim 1 , wherein the second prompt indicates whether a current digit force or a current digit pressure should be changed.

14. The method of claim 1 , further comprising controlling, via the control system, the apparatus to provide a third prompt based, at least in part, on the image quality metric.

15. The method of claim 14 , wherein the third prompt indicates that a finger moisture level should be changed.

16. The method of claim 1 , further comprising determining an acceptable image quality force range or an acceptable image quality pressure range associated with image quality metrics that equal or exceed an image quality metric threshold.

17. The method of claim 16 , further comprising associating the acceptable image quality force range or the acceptable image quality pressure range with a person and storing the acceptable image quality force range or the acceptable image quality pressure range in a memory.

18. The method of claim 17 , further comprising:

performing an authentication process; and

applying the acceptable image quality force range or the acceptable image quality pressure range during the authentication process.

19. The method of claim 1 , further comprising:

performing a digit enrollment process;

determining digit characteristic data in addition to fingerprint image characteristic data during the digit enrollment process; and

storing the digit characteristic data in a memory.

20. The method of claim 19 , further comprising:

performing an authentication process; and

applying the digit characteristic data during the authentication process.

21. The method of claim 19 , wherein the digit characteristic data includes one or more of digit orientation data, digit force data, digit pressure data or digit dryness data.

22. The method of claim 1 , wherein the control system determines the digit force or the digit pressure according to fingerprint sensor data received from the fingerprint sensor system.

23. The method of claim 22 , wherein the fingerprint sensor data comprise ultrasonic fingerprint sensor data.

24. The method of claim 23 , wherein the ultrasonic fingerprint sensor data are received via an electrode layer proximate a piezoelectric layer.

25. The method of claim 23 , wherein the ultrasonic fingerprint sensor data are received via an array of ultrasonic sensor pixels.

26. The method of claim 1 , further comprising:

detecting a digit dryness condition based, at least in part, on fingerprint sensor data received from the fingerprint sensor system; and

controlling, via the control system, the apparatus to provide a third prompt corresponding to the digit dryness condition.

27. The method of claim 1 , further comprising performing a spoof detection process based, at least in part, on the digit force or the digit pressure.

28. An apparatus, comprising:

a fingerprint sensor system;

a user interface system; and

a control system configured to:

determine whether a digit is on an outer surface of the apparatus in a fingerprint sensor system area;

responsive to determining that the digit is on the outer surface of the apparatus in the fingerprint sensor system area, receive fingerprint sensor data from the fingerprint sensor system corresponding to the digit;

determine, according to the fingerprint sensor data, a digit force or a digit pressure of the digit on the outer surface;

obtain fingerprint image data;

determine an image quality metric corresponding to the fingerprint image data; and

control the user interface system to provide a prompt corresponding to the digit force or the digit pressure, wherein the second prompt is based, at least in part, on the image quality metric.

29. The apparatus of claim 28 , wherein the apparatus further comprises a display device and wherein providing the prompt involves presenting a graphical user interface (GUI) on the display device.

30. The apparatus of claim 29 , wherein the GUI is configured to indicate a current digit force or a current digit pressure.

31. The apparatus of claim 30 , wherein the GUI is configured to indicate whether the current digit force or the current digit pressure is within an acceptable range.

32. The apparatus of claim 30 , wherein the GUI is configured to indicate that the current digit force or the current digit pressure is not within an acceptable range and wherein the GUI includes a prompt to change the current digit force or the current digit pressure.

33. The apparatus of claim 30 , wherein the GUI corresponds with a force calibration phase or a pressure calibration phase of a user enrollment process.

34. The apparatus of claim 30 , wherein the GUI corresponds with a fingerprint capture phase of a user enrollment process.

35. The apparatus of claim 30 , wherein the GUI corresponds with an authentication process.

36. An apparatus, comprising:

a fingerprint sensor system;

a user interface system; and

control means for:

controlling the user interface system to provide a first prompt to place a digit on an outer surface of the apparatus in a fingerprint sensor system area;

receiving fingerprint sensor data from the fingerprint sensor system corresponding to the digit;

determining, based at least in part on the fingerprint sensor data, a digit force or a digit pressure of the digit on the outer surface of the apparatus;

obtaining fingerprint image data;

determining an image quality metric corresponding to the fingerprint image data; and

controlling the user interface system to provide a second prompt corresponding to the digit force or the digit pressure, wherein the second prompt is based, at least in part, on the image quality metric.

37. The apparatus of claim 36 , further comprising a display device, wherein providing the second prompt involves presenting a graphical user interface (GUI) on the display device.

38. The apparatus of claim 37 , wherein the GUI is configured to indicate a current digit force or a current digit pressure.

39. The apparatus of claim 38 , wherein the GUI is configured to indicate whether the current digit force or the current digit pressure is within an acceptable range.

40. One or more non-transitory media having software stored thereon, the software including instructions for controlling one or more devices to perform a method, the method comprising:

controlling, via a control system, an apparatus to provide a first prompt to place a digit on an outer surface of the apparatus in a fingerprint sensor system area;

determining, via the control system, a digit force or a digit pressure of the digit on the outer surface of the apparatus;

obtaining fingerprint image data;

determining an image quality metric corresponding to the fingerprint image data; and

controlling, via the control system, the apparatus to provide a second prompt corresponding to the digit force or the digit pressure, wherein the second prompt is based, at least in part, on the image quality metric.

41. The one or more non-transitory media of claim 40 , wherein providing the second prompt involves presenting a graphical user interface (GUI) on a display device of the apparatus.

42. The one or more non-transitory media of claim 41 , wherein the GUI is configured to indicate a current digit force or a current digit pressure.

43. The one or more non-transitory media of claim 42 , wherein the GUI is configured to indicate whether the current digit force or the current digit pressure is within an acceptable range.