A method and a device for verifying liveness of a finger

Abstract

A method (700) for verifying liveness of a finger (102) of a user by capturing a first fingerprint sample (402) from the finger (102) placed on a display (104) by using a first sensor (106) placed under the display (104). The method (700) may comprise transmitting (702) light, by using a first light transmitting display area of the display (104), towards a first area of the finger (102), wherein the first light transmitting display area (108) is smaller than a first sensor area; capturing (704) reflected light from the finger (102) by the first sensor (104), wherein the reflected light (114) is transmitted through the display (104); and identifying (706) a first feature of the first fingerprint sample (402) by using the reflected light (114), wherein the first feature comprises scattered light from the finger (102), wherein the light transmitted from the display (104) comprises a first light component with a first wavelength from a first area of the display (104).

1 .- 12 . (canceled) 
     
     
         13 . A method for verifying liveness of a finger of a user, the method comprising:
 capturing a fingerprint sample from the finger placed on a display by using a first sensor placed within or under the display;   extracting scattered light features from the fingerprint sample;   comparing the scattered light features with a light scattering template; and   if a match is found, generating a liveness acceptance signal, else generating a liveness rejection signal;   wherein capturing the fingerprint sample involves
 transmitting light of a first light component with a first wavelength from the display towards the finger, and 
 capturing light reflected from the finger by the first sensor, wherein the reflected light is transmitted through the display. 
   
     
     
         14 . The method according to  claim 13 , wherein capturing the fingerprint sample comprises:
 transmitting light, from a first light transmitting display area of the display, towards the finger, wherein the first light transmitting display area is divided into subareas, wherein the light transmitted from the different subareas comprises different light components with different wavelengths; and   capturing light reflected from the finger by the first sensor, wherein the reflected light is transmitted through the display.   
     
     
         15 . The method according to  claim 13 , wherein capturing the fingerprint sample comprises:
 capturing a first fingerprint sample by
 transmitting light of a first light component with a first wavelength from the display towards the finger, and 
 capturing light reflected from the finger by the first sensor, wherein the reflected light is transmitted through the display; 
   capturing a second fingerprint sample by
 transmitting light of a second light component with a second wavelength from the display towards the finger, and 
 capturing light reflected from the finger by the first sensor wherein the reflected light is transmitted through the display; and 
   generating the fingerprint sample from the first and the second fingerprint samples as a composite fingerprint sample of the first and the second fingerprint samples.   
     
     
         16 . The method according to  claim 13 , further comprising:
 determining a surrounding temperature and/or a surrounding brightness; and   determining the wavelength(s) to be used in the step of transmitting light towards the finger based on the surrounding temperature and/or the surrounding brightness.   
     
     
         17 . The method according to  claim 13 , wherein the light scattering template comprises information about how light with different wavelength behave in the finger. 
     
     
         18 . The method according to  claim 17 , wherein the light scattering template further comprises information about how light with different wavelength behave in different spoof-materials. 
     
     
         19 . The method according to  claim 13 , wherein capturing the fingerprint sample comprises illuminating only a part of the finger. 
     
     
         20 . A mobile device configured to verify liveness of a finger of a user, the mobile device comprising:
 a display configured to transmit light towards the finger placed on the display, wherein the light includes a first light component with a first wavelength;   a first sensor placed under or within the display, wherein the first sensor is configured to capture a fingerprint sample from the finger placed on the display; and   a processor configured to
 extract scattered light features from the first fingerprint sample, 
 compare the scattered light features with a light scattering template, and 
 if a match is found, generate a liveness acceptance signal, else generate a liveness rejection signal. 
   
     
     
         21 . The mobile device according to  claim 20 , further comprising a second sensor configured to determine a surrounding temperature and/or a surrounding brightness;
 wherein the first wavelength is determined based on the surrounding temperature and/or the surrounding brightness.   
     
     
         22 . The mobile device according to  claim 20 , wherein the light scattering template comprises information about how light with different wavelength behave in the finger. 
     
     
         23 . The mobile device according to  claim 22 , wherein the light scattering template further comprises information about how light with different wavelength behave in different spoof-materials. 
     
     
         24 . The mobile device according to  claim 20 , wherein the display is configured to transmit light towards only a part of the finger placed on the display. 
     
     
         25 . A system configured to verify liveness of a finger of a user, the system comprising a mobile device and a server;
 the mobile device including
 a display configured to transmit light towards the finger placed on the display, wherein the light comprises a first light component with a first wavelength, and 
 a first sensor placed under or within the display, wherein the first sensor is configured to capture a fingerprint sample from the finger placed on the display, 
 wherein the mobile device is configured to send the first fingerprint sample to the server; 
   the server including a control unit, a transceiver, and a memory, wherein the server is configured to
 execute an extraction function to extract scattered light features from the fingerprint sample, and 
   execute a comparison function to compare the scattered light features with a light scattering template, and if a match is found, generate a liveness acceptance signal to the mobile device, else generate a liveness rejection signal to the mobile device.