Method of guiding a user of a portable electronic device

1. A method of guiding a user of a portable electronic device, the electronic device comprising a display unit configured to display a graphical user interface (GUI), a fingerprint sensor having an array of pixels and configured for capturing a fingerprint representation of a fingerprint pattern of a finger, and a control unit connected to and configured to control an operation of the display unit and the fingerprint sensor, wherein the method comprises:

acquiring, at a first instance in time, a first partial fingerprint image of a corresponding first portion of a fingerprint pattern using the fingerprint sensor;

determining, based on the first partial fingerprint image, a first arrangement of the finger in relation to the fingerprint sensor;

selecting a first user guidance based on the first finger arrangement;

providing the first user guidance to the user for rearranging the finger in relation to the fingerprint sensor;

acquiring, at a second instance in time, a second partial fingerprint image of a corresponding second portion of the fingerprint pattern using the fingerprint sensor;

determining, based on the second partial fingerprint image, a second arrangement of the finger in relation to the fingerprint sensor;

determining a difference between the first and the second finger arrangement;

estimating an experience level for the user;

selecting a second user guidance taking into account both the first and the second finger arrangement, wherein the selected second user guidance is further based on the estimated experience level for the user; and

providing the second user guidance to the user for arranging the finger in relation to the fingerprint sensor.

2. The method according to claim 1 , wherein the selected second user guidance is further based on a difference between the first and the second finger arrangement.

3. The method according to claim 1 , further comprising:

determining a quality metric for the first partial fingerprint image,

wherein selecting the first user guidance comprises forming a combined single visualization of a position of the finger in relation to the fingerprint sensor and the resulting quality metric.

4. The method according to claim 3 , wherein determining the quality metric for the first partial fingerprint image comprises at least one of:

determining an area of the fingerprint pattern of the finger as compared to a total area of the fingerprint sensor;

determining a contrast level for the first partial fingerprint image; and

determining an indication of a possibility of successful feature extraction from the first partial fingerprint image.

5. The method according to claim 1 , wherein selecting the second user guidance comprises:

forming a visualization to be provided within GUI of both the first and the second finger arrangement.

6. The method according to claim 1 , wherein the first and the second arrangement of the finger in relation to the fingerprint sensor corresponds to at least one of a lateral position of the finger in relation to the fingerprint sensor and an indication of a pressure level of the finger contacting the fingerprint sensor.

7. The method according to claim 1 , wherein the first and the second user guidance is context adapted depending on the first and the second fingerprint arrangement.

8. The method according to claim 1 , wherein the first user guidance is a graphical representation of relative position of the finger in relation to the fingerprint sensor.

9. The method according to claim 8 , wherein the graphical representation comprises a histogram.

10. The method according to claim 9 , wherein the histogram is configured to show a lateral position of the finger in relation to the fingerprint sensor.

11. The method according to claim 8 , wherein the graphical representation comprises a heat map.

12. The method according to claim 1 , wherein selecting the first guidance comprises:

comparing the first finger arrangement with a desired arrangement of the finger in relation to the fingerprint sensor, and

determining a graphical representation corresponding to a result of the comparison.

13. The method according to claim 1 , wherein the fingerprint sensor is mounted at a side of the electronic device, essentially perpendicular to the display unit.

14. The method according to claim 1 , wherein the display unit is arranged at a front side of the electronic device and the fingerprint sensor is mounted at a back side of the electronic device.

15. The method according to claim 14 , wherein the first user guidance is visualized within the GUI at a relative position corresponding to a position of mounting the fingerprint sensor at the back side of the electronic device.

16. The method according to claim 1 , wherein selecting the second user guidance based on the first and the second finger arrangement comprises:

comparing the difference between first finger arrangement and the second finger arrangement with a desired rearrangement of the finger in relation to the fingerprint sensor.

17. The method according to claim 16 , wherein if the difference between first finger arrangement and the second finger arrangement is less than the desired rearrangement of the finger in relation to the fingerprint sensor, then the second user guidance is selected to be an instruction video for guiding the user in using the fingerprint sensor.

18. The method according to claim 16 , wherein the desired rearrangement corresponds to at least a 10% repositioning of the finger in relation to the fingerprint sensor.

19. The method according to claim 1 , wherein at least one of the first and the second user guidance is provided to the user by displaying at least one of the first and the second user guidance through the GUI.

20. The method according to claim 1 , wherein the second user guidance is different from the first user guidance.

21. The method according to claim 1 , wherein determining the first and the second finger arrangement further comprises:

determining a quality metric for the first and the second partial fingerprint image, respectively.

22. A portable electronic device, comprising:

a display unit configured to display a graphical user interface (GUI);

a fingerprint sensor having an array of pixels and configured for capturing a fingerprint representation of a fingerprint pattern of a finger, and

a control unit electrically connected to the fingerprint sensor and the display unit, wherein the control unit is configured to:

acquire, at a first instance in time, a first partial fingerprint image of a corresponding first portion of a fingerprint pattern using the fingerprint sensor;

determine, based on the first partial fingerprint image, a first arrangement of the finger in relation to the fingerprint sensor;

select a first user guidance based on the first finger arrangement;

provide the first user guidance to the user for rearranging the finger in relation to the fingerprint sensor;

acquire, at a second instance in time, a second partial fingerprint image of a corresponding second portion of the fingerprint pattern using the fingerprint sensor;

determine, based on the second partial fingerprint image, a second arrangement of the finger in relation to the fingerprint sensor;

determine a difference between the first and the second finger arrangement;

estimate an experience level for the user;

select a second user guidance taking into account both the first and the second finger arrangement, wherein the selected second user guidance is further based on the estimated experience level for the user; and

provide the second user guidance to the user for arranging the finger in relation to the fingerprint sensor.

23. The portable electronic device according to claim 22 , wherein the fingerprint sensor is employing capacitive sensing technology.

24. The portable electronic device according to claim 22 , wherein the fingerprint sensor is mounted at a side of the electronic device, essentially perpendicular to the display unit.

25. The portable electronic device according to claim 22 , wherein the control unit is further configured for general operation of the portable electronic device.

26. The portable electronic device according to claim 22 , wherein the portable electronic device is a mobile phone.

27. A computer program product comprising a non-transitory computer readable medium having stored thereon computer program means for a control unit adapted for controlling a portable electronic device, the electronic device comprising a display unit configured to display a graphical user interface (GUI), a fingerprint sensor having an array of pixels and configured for capturing a fingerprint representation of a fingerprint pattern of a finger, and a control unit connected to and configured to control an operation of the display unit and the fingerprint sensor, wherein the computer program product comprises:

code for acquiring, at a first instance in time, a first partial fingerprint image of a corresponding first portion of a fingerprint pattern using the fingerprint sensor;

code for determining, based on the first partial fingerprint image, a first arrangement of the finger in relation to the fingerprint sensor;

code for selecting a first user guidance based on the first finger arrangement;

code for providing the first user guidance to the user for rearranging the finger in relation to the fingerprint sensor;

code for acquiring, at a second instance in time, a second partial fingerprint image of a corresponding second portion of the fingerprint pattern using the fingerprint sensor;

code for determining, based on the second partial fingerprint image, a second arrangement of the finger in relation to the fingerprint sensor;

code for determining a difference between the first and the second finger arrangement;

code for estimating an experience level for the user;

code for selecting a second user guidance taking into account both the first and the second finger arrangement, wherein the selected second user guidance is further based on the estimated experience level for the user; and

code for providing the second user guidance to the user for arranging the finger in relation to the fingerprint sensor.