Method and system for biometric recognition
High quality, high contrast images of an iris and the face of a person are acquired in rapid succession in either sequence by a single sensor and one or more illuminators, preferably within less than one second of each other, by changing the data acquisition settings or illumination settings between each acquisition.
1. A system for acquiring iris and face biometric features, the system comprising:
a depth measurement sensor configured to determine a distance of an image sensor from a subject;
at least one light source; and
the image sensor, the image sensor configured to:
acquire, at a first time instant, a first image comprising a biometric feature of a face of the subject, the face illuminated by light of a first wavelength from the at least one light source set to a first intensity magnitude suitable for acquiring the first image at the determined distance; and
acquire, at a second time instant, a second image comprising a biometric feature of an iris of the subject, the iris illuminated by light of a second wavelength from the at least one light source set to a second intensity magnitude suitable for acquiring the second image at the determined distance, wherein the second time instant is within a predetermined time period of the first time instant sufficient to link the first image and the second image to the same subject.
2. The system of claim 1 , wherein the depth measurement sensor is configured to determine the distance of the image sensor from the subject by determining at least one of a diameter of the iris or a separation distance between two eyes of the subject.
3. The system of claim 1 , further comprising at least one processor configured to perform biometric recognition using the first image comprising the biometric feature of the face, and perform biometric recognition the second image comprising the biometric feature of the iris.
4. The system of claim 1 , further comprising at least one processor configured to determine an orientation of the face using the first image, and determine an expected orientation and location of the iris on the second image using the determined orientation of the face.
5. The system of claim 1 , further comprising at least one processor configured to perform registration between the first image comprising the biometric feature of the face and the second image comprising the biometric feature of the iris.
6. The system of claim 1 , wherein the at least one light source comprises a visible light illuminator configured to provide the light of the first wavelength, and an infra-red light illuminator configured to provide the light of the second wavelength.
7. The system of claim 1 , further comprising at least one processor configured to adjust at least one of the light of the first wavelength or the light of the second wavelength responsive to the determined distance.
8. The system of claim 1 , wherein the depth measurement sensor is configured to determine the distance by comparing at least one of a diameter of the iris or a separation distance between two eyes of the subject, with one or more values of a reference table.
9. The system of claim 1 , further comprising an imaging controller configured to adjust at least one of: sensor gain, sensor offset, illumination pulse width, shutter speed, focus, zoom or integration time for image acquisition, between the acquisition of the first image and the acquisition of the second image.
10. The system of claim 1 , wherein the image sensor is configured to acquire at least one of the first image or the second image while the subject is in motion.
11. A method for biometric acquisition, the method comprising:
determining, by a depth measurement sensor, a distance of an image sensor from a subject;
acquiring, by the image sensor at a first time instant, a first image comprising a biometric feature of an iris of the subject, the iris illuminated by light of a first wavelength set to a first intensity magnitude suitable for acquiring the first image at the determined distance; and
acquiring, by the image sensor at a second time instant, a second image of a biometric feature of a face of the subject, the face illuminated by light of a second wavelength set to a second intensity magnitude suitable for acquiring the second image at the determined distance, wherein the second time instant is within a predetermined time period of the first time instant sufficient to link the first image and the second image to the same subject.
12. The method of claim 11 , wherein determining the distance of the image sensor from the subject comprises determining at least one of a diameter of the iris or a separation distance between two eyes of the subject.
13. The method of claim 11 , further comprising performing biometric recognition using the first image comprising the biometric feature of the iris, and performing biometric recognition using the second image comprising the biometric feature of the face.
14. The method of claim 11 , further comprising determining an orientation of the face using the second image, and determining an expected orientation and location of the iris on the first image using the determined orientation of the face.
15. The method of claim 11 , further comprising performing registration between the first image comprising the biometric feature of the iris and the second image of the biometric feature of the face.
16. The method of claim 11 , wherein the light of the second wavelength is provided by a visible light illuminator and the light of the first wavelength is provided by an infra-red light illuminator.
17. The method of claim 11 , further comprising adjusting at least one of the light of the first wavelength or the light of the second wavelength responsive to the determined distance.
18. The method of claim 11 , wherein determining the distance comprises comparing at least one of a diameter of the iris or a separation distance between two eyes of the subject, with one or more values of a reference table.
19. The method of claim 11 , further comprising adjusting, by an imaging controller, at least one of: sensor gain, sensor offset, illumination pulse width, shutter speed, focus, zoom or integration time for image acquisition, between the acquisition of the first image and the acquisition of the second image.
20. The method of claim 11 , wherein the acquisition of at least one of the first image or the second image occurs while the subject is in motion.