Agile biometric camera with bandpass filter and variable light source

• US 10,121,073 B2
• Filed: 02/12/2015
• Issued: 11/06/2018
• Est. Priority Date: 02/12/2014
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Smits, Gerard Dirk
• Primary Examiner(s): Perungavoor, Sathyanaraya V
• Assistant Examiner(s): Young, Patricia I
• Application Number:
  US14/621,078
• Publication Number:
  US 20150227790A1
• Time in Patent Office: 1,363 Days
• Field of Search: 348 78
• CPC Class Codes: G06V 40/19 Sensors therefor

Abstract

A system and method for authenticating a user of a device. A biometric camera system includes a light source having a variable illumination wavelength output, and a camera including an imaging sensor and a bandpass filter for filtering ambient illumination received at the imaging sensor. An optical image of a user, for example an image of an iris, is generated by illumination from the light source, filtered by the bandpass filter, and received at the imaging sensor. An authentication status of the user can be determined using the image.

Claims

1. A biometric camera system, comprising:

a light source disposed on a mobile device, the light source to output a first pulse of near infrared (NIR) light with a first center wavelength at a first time to illuminate an iris, and a second pulse of NIR light with a second center wavelength at a second time to illuminate the iris;

a biometric camera disposed on the mobile device, the biometric camera comprising;

an imaging lens;

a bandpass filter disposed along a focal axis of the imaging lens to receive light including the first and second pulses of NIR light reflected from the iris, the bandpass filter to filter light that lies outside of a range of wavelengths and to transmit light that lies within the range of wavelengths, the first and second pulses of NIR light reflected from the iris being transmitted through the bandpass filter;

an imaging sensor disposed along the focal axis of the imaging lens such that the bandpass filter is disposed between the imaging lens and the imaging sensor, the imaging sensor having a plurality of sensor regions, the imaging sensor to capture the first pulse of NIR light reflected from the iris and transmitted through the bandpass filter in a first sensor region of the plurality of sensor regions as a first captured pulse, and convert the first captured pulse into a first electrical signal, the imaging sensor to capture the second pulse of NIR light reflected from the iris and transmitted through the bandpass filter in a second sensor region of the plurality of sensor regions as a second captured pulse, and convert the second captured pulse into a second electrical signal, the first and second sensor regions being non-overlapping; and

a processor to generate first and second iris images in response to the first and second electrical signals, respectively, compare a characteristic of the first iris image to a characteristic of the second iris image to choose a selected iris image from the first and second iris images, compare the selected iris image to a previously registered iris image stored in an iris database, and grant authentication when the selected iris image matches the previously registered iris image, the characteristics of the first and second iris images include spectral reflections off of a cornea of an eye, the selected iris image having a maximum spectral reflection between the first and second iris images.

2. The system according to claim 1, wherein:

the tunable light source to scan through the range of wavelengths of NIR light to illuminate the eye with a series of substantially single wavelengths of NIR light;

the imaging sensor captures the series of substantially single wavelengths of NIR light reflected from the iris as a series of captured wavelengths, and converts the series of captured wavelengths into a series of scanned electrical signals; and

the processor to generate a series of scanned images from the series of scanned electrical signals, compare a characteristic of each scanned image to identify a best illuminated scanned image from the series of scanned images, and select the wavelength of NIR light that was used to generate the best illuminated scanned image as the substantially single wavelength of NIR light to be output by the tunable light source.

3. The system according to claim 1, wherein:

the tunable light source to scan through the range of wavelengths of NIR light to illuminate the eye with a series of wavelengths of NIR light to generate spectral reflections off of a cornea of the eye; and

the processor to select the substantially single wavelength of NIR light from the range of wavelengths of NIR light based on the wavelength of the series of wavelengths that has a maximum spectral reflection.

4. A biometric camera system, comprising:

a light source disposed on a mobile device, the light source to output a first pulse of near infrared (NIR) light with a first center wavelength at a first time to illuminate an iris, and a second pulse of NIR light with a second center wavelength at a second time to illuminate the iris, the light source to include a vertical cavity surface emitting laser (VCSEL), the VCSEL being tunable to output the first and second pulses of NIR light;

a biometric camera disposed on the mobile device, the biometric camera comprising;

an imaging lens;

a bandpass filter disposed along a focal axis of the imaging lens to receive light including the first and second pulses of NIR light reflected from the iris, the bandpass filter to filter light that lies outside of a range of wavelengths and to transmit light that lies within the range of wavelengths, the first and second pulses of NIR light reflected from the iris being transmitted through the bandpass filter;

an imaging sensor disposed along the focal axis of the imaging lens such that the bandpass filter is disposed between the imaging lens and the imaging sensor, the imaging sensor having a plurality of sensor regions, the imaging sensor to capture the first pulse of NIR light reflected from the iris and transmitted through the bandpass filter in a first sensor region of the plurality of sensor regions as a first captured pulse, and convert the first captured pulse into a first electrical signal, the imaging sensor to capture the second pulse of NIR light reflected from the iris and transmitted through the bandpass filter in a second sensor region of the plurality of sensor regions as a second captured pulse, and convert the second captured pulse into a second electrical signal, the first and second sensor regions being non-overlapping; and

a processor to generate first and second iris images in response to the first and second electrical signals, respectively, compare a characteristic of the first iris image to a characteristic of the second iris image to choose a selected iris image from the first and second iris images, compare the selected iris image to a previously registered iris image stored in an iris database, and grant authentication when the selected iris image matches the previously registered iris image.

5. The system according to claim 4, wherein the biometric camera further comprises a visible light filter disposed between the imaging lens and the imaging sensor, the visible light filter to substantially reduce the amplitudes of substantially all wavelengths of visible light.

6. The system according to claim 4,

further comprising a visible-light camera disposed on the mobile device that captures a visible-light image of the iris;

and

wherein the processor to select the substantially single wavelength of NIR light based on the position of the iris relative to the position of the visible-light camera.

7. A method of biometric identification, the method comprising:

outputting a substantially single wavelength of near infrared (NIR) light from a range of wavelengths of NIR light to illuminate an iris of an eye, the substantially single wavelength of NIR light to reflect off of the iris;

substantially reducing the amplitudes of the wavelengths of light that lie outside of the range of wavelengths of NIR light, and passing all wavelengths of light that lie within the range of wavelengths of NIR light, including the substantially single wavelength of NIR light reflected from the iris, with relatively little reduction in the amplitudes of the wavelengths of light within the range of wavelengths of NIR light as compared to the wavelengths of light that lie outside of the range of wavelengths of NIR light;

capturing the substantially single wavelength of NIR light reflected from the iris and transmitted through the bandpass filter as a captured wavelength, and converting the captured wavelength into an electrical signal;

and

selecting the substantially single wavelength of NIR light to be output by the tunable light source from the range of wavelengths of NIR light based on light reflected from the iris, generating a current iris image in response to the electrical signal, comparing the current iris image with a previously registered iris image stored in an iris database, and granting authentication when the current iris image matches the previously registered iris image.

8. The method according to claim 7, further comprising scanning through the range of wavelengths of NIR light to illuminate the eye with a series of wavelengths of NIR light to generate spectral reflections off of a cornea of the eye, and

selecting the substantially single wavelength of NIR light to be output from the range of wavelengths of NIR light based on the wavelength of the series of wavelengths that has a maximum spectral reflection.

9. The method according to claim 7, further comprising:

scanning through the range of wavelengths of NIR light to illuminate the eye with a series of substantially single wavelengths of NIR light;

capturing the series of substantially single wavelengths of NIR light reflected from the iris as a series of captured wavelengths, and converting the series of captured wavelengths into a series of scanned electrical signals; and

generating a series of scanned images from the series of scanned electrical signals, comparing a characteristic of each scanned image to identify a best illuminated scanned image from the series of scanned images, and selecting the wavelength of NIR light that was used to generate the best illuminated scanned image as the substantially single wavelength of NIR light to be output.

10. The method according to claim 7, further comprising capturing the substantially single wavelength of NIR light in a first sensor region of a plurality of sensor regions, each sensor region having a plurality of imaging elements.

11. The method according to claim 10, and further comprising reading less than all of the imaging elements in the first sensor region to form the electrical signal.

12. The method according to claim 7, further comprising:

capturing a visible-light image of the iris; and

selecting the substantially single wavelength of NIR light based on the position of the iris relative to the position of the visible-light camera.

13. A method of biometric identification, the method comprising:

outputting a first pulse of near infrared (NIR) light with a first center wavelength at a first time to illuminate an iris, and a second pulse of NIR light with a second center wavelength at a second time to illuminate the iris, the first pulse and the second pulse being output by a light source, the light source includes an LED array that has a first region that outputs the first pulse of NIR light with the first center wavelength, and a second region that outputs the second pulse of NIR light with the second center wavelength;

receiving light including the first and second pulses of NIR light reflected from the iris, filtering light that lies outside of a range of wavelengths, and transmitting light that lies within the range of wavelengths, the first and second pulses of NIR light reflected from the iris being transmitted through the bandpass filter;

capturing the first pulse of NIR light reflected from the iris and transmitted through the bandpass filter in a first sensor region of the plurality of sensor regions as a first captured pulse, and converting the first captured pulse into a first electrical signal;

capturing the second pulse of NIR light reflected from the iris and transmitted through the bandpass filter in a second sensor region of the plurality of sensor regions as a second captured pulse, and converting the second captured pulse into a second electrical signal, the first and second sensor regions being non-overlapping;

generating first and second iris images in response to the first and second electrical signals, respectively, and comparing a characteristic of the first iris image to a characteristic of the second iris image to choose a selected iris image; and

comparing the selected iris image with a previously registered iris image stored in an iris database, and granting authentication when the selected iris image matches the previously registered iris image.

14. A mobile apparatus for biometric user authentication, the apparatus comprising:

a memory to store an iris database;

a light source having a plurality of lighting elements, the light source to output;

a first pulse of light with a first number of lighting elements at a first time to illuminate a scene that includes an iris and a number of other features, and

a second pulse of light with a second number of lighting elements selected from the first number of lighting elements at a second time to illuminate substantially only the iris, the second number of lighting elements being less than the first number of lighting elements, and being selected based on a location of the iris; and

a camera, comprising;

an imaging lens;

a bandpass filter disposed along a focal axis of the imaging lens to receive light including the first and second pulses of light reflected from the scene and substantially only the iris, respectively, the bandpass filter to filter light that lies outside of a range of wavelengths and to transmit light that lies within the range of wavelengths, the first and second pulses of light reflected from the scene and substantially only the iris, respectively, being transmitted through the bandpass filter; and

an imaging sensor disposed along the focal axis of the imaging lens such that the bandpass filter is disposed between the imaging lens and the imaging sensor, the imaging sensor to capture the first pulse of light reflected from the scene and transmitted through the bandpass filter as a first captured pulse, and convert the first captured pulse into a first electrical signal, the imaging sensor to capture the second pulse of light reflected from substantially only the iris and transmitted through the bandpass filter as a second captured pulse, and convert the second captured pulse into a second electrical signal; and

a processor to generate an image of the scene in response to the first electrical signal, determine the location of the iris from the image of the scene, generate an image of substantially only the iris in response to the second electrical signal, compare the image of substantially only the iris with a previously registered iris image stored in the iris database to determine an authentication status, and grant an authentication when the image of substantially only the iris matches the previously registered iris image.

15. The apparatus according to claim 14, wherein the first pulse of light is output at a low power level and the second pulse of light is output at a higher power level.

16. The apparatus according to claim 14 wherein each lighting element includes a plurality of light emitting diodes (LEDs), the plurality of LEDs in each lighting element including LEDs that emit visible light and LEDs that emit near infrared light.

17. The apparatus according to claim 14, wherein the plurality of lighting elements include an array of light emitting diodes (LEDs), and wherein LEDs of the array are individually addressable.

18. The apparatus according to claim 17, wherein a first portion of the array comprises LEDs operable to emit at a first wavelength, and a second portion of the array comprises LEDs operable to emit at a second wavelength, wherein the first wavelength is greater than the second wavelength.

19. The apparatus according to claim 17, wherein LEDs of the array are disposed to emit illumination at varying angles with respect to a top surface of the array.