IMAGE-BASED HEAD POSITION TRACKING METHOD AND SYSTEM

• US 20130083976A1
• Filed: 10/03/2011
• Published: 04/04/2013
• Est. Priority Date: 10/03/2011
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Ragland, Richard R.
• Granted Patent: US 8,879,801 B2
• Time in Patent Office: Days
• US Class Current: 382/117
• CPC Class Codes: A61B 3/113 for determining or recording eye movement
• CPC Class Codes: G06F 18/00 Pattern recognition
• CPC Class Codes: G06F 3/011 Arrangements for interaction with the human body, e.g. for user immersion in virtual reality blind teaching G09B21/00
• CPC Class Codes: G06F 3/012 Head tracking input arrangements
• CPC Class Codes: G06F 3/013 Eye tracking input arrangements G06F3/015 takes precedence
• CPC Class Codes: G06V 40/168 Feature extraction; Face representation
• CPC Class Codes: G06V 40/193 Preprocessing; Feature extraction

Abstract

Systems and methods for tracking a head position of a user include obtaining digital images of the user'"'"'s head, processing the images to locate anatomical structures beneath the visible surface, and using those determined locations as inputs to a computing device. In an embodiment, images of a user'"'"'s face are processed to identify the irises of the eyes, identify pixels along a boundary between each iris and the surrounding sclera, determine an ellipse defined by the identified iris-sclera boundary pixels, determine a distance-to-pixel ratio based on a pixel length of a long axis of such an ellipse compared to a known or presumed diameter of the iris, locating the iris in a three-axis coordinate system, determining an optical axis vector of the eye in the three-axis coordinate system, and calculating a center of the eyeball based on the optical axis vector and a known or presumed eyeball radius.

Claims

1. A method for controlling a computing device, comprising:

obtaining a digital image of a face of a user of the computing device with a digital camera;

processing the digital image to determine a position and orientation of an anatomical structure of the user that is beneath a surface of the user'"'"'s skin; and

translating the position determined and the orientation of the anatomical structure into an input command.

2. The method of claim 1, wherein processing the obtained image to determine a position and orientation of the anatomical structure of the user that is beneath a surface of the user'"'"'s skin comprises determining a spherical center location of at least one of the user'"'"'s eyeballs.

3. The method of claim 2, wherein determining a spherical center point location of a user'"'"'s eyeball comprises:

performing a least squares fit of iris-to-sclera boundary pixels in the digital image to determine an ellipse equation characterizing the imaged iris;

determining coordinates in a three-dimensional coordinate system of a center point of the iris based on the ellipse equation of the imaged iris;

calculating an optical axis vector of the iris oriented in the three-axis coordinate system based on the center point of the iris and on the ellipse equation of the imaged iris;

projecting the optical axis vector into the user'"'"'s eyeball; and

determining a center point of the user'"'"'s eyeball by measuring one eyeball radius distance along the projected optical axis vector from the surface of the iris.

4. The method of claim 3, further comprising:

repeating operations to determine a center point for both eyeballs; and

determining an orientation of the user'"'"'s head within the digital image based the determined eyeball center points and an inter-eyeball distance between the determined eyeball center points.

5. A method for determining a radius of an eyeball, comprising:

prompting a user to look in a first direction;

obtaining a digital image of the user'"'"'s face;

calculating a first optical axis vector for an eye based on the obtained image;

prompting the user to look in a second direction;

obtaining a digital image of the user'"'"'s face;

calculating a second optical axis vector for an eye based on the obtained image;

determining an intersection point of the first and second optical axis vectors; and

calculating the radius of the eyeball as a distance between the determined intersection point of the first and second optical axis vectors and a surface of the eyeball.

6. A method for implementing a user input on a graphical user interface, comprising:

determining a location of an eyeball center point for each of a user'"'"'s eyes;

calculating an optical axis vector for each of the user'"'"'s eyes based on the determined location of an eyeball center point for each of the user'"'"'s eyes;

calculating a first visual axis for one of the user'"'"'s eyes and a second visual axis for the other of the user'"'"'s eyes based on the eyeball center points and the optical axes vectors;

determining the user'"'"'s point-of-gaze, wherein the point-of-gaze comprises a point of intersection of the first and second visual axes; and

selecting a user input feature on the graphical user interface when the user'"'"'s point-of-gaze is stationary for a predetermined duration of time.

7. The method of claim 6, wherein calculating the first visual axis and the second visual axis each comprises:

calculating an eyeball centers line between the eyeball center points based on the determined location of an eyeball center point for each of the user'"'"'s eyes;

calculating an eyeball centers extension line by laterally extending the eyeball centers line by an offset distance past the eyeball center point of the one of the user'"'"'s eyes; and

calculating a visual axis as a line between an origin point of the optical axis vector and an endpoint of eyeball centers extension line, wherein the endpoint of the eyeball centers extension line is ipsilateral to the one of the user'"'"'s eyes.

8. The method of claim 7, wherein the offset distance is determined by:

prompting a user to look at a gaze target presented on the display screen at a known position;

calculating an instantaneous visual axis of the one of the user'"'"'s eyes, wherein the instantaneous visual axis intersects the gaze target and the origin point of the optical axis vector;

calculating an intersection point of the instantaneous visual axis and the eyeball centers extension line; and

measuring a distance between an eyeball center point and the intersection point, wherein the eyeball center point is ipsilateral to the one of the user'"'"'s eyes.

9. The method of claim 6, wherein determining the location of an eyeball center point for each of the user'"'"'s eyes comprises:

performing a least squares fit of the iris-to-sclera boundary pixels in the digital image to determine an ellipse equation characterizing the imaged iris;

determining coordinates in a three-dimensional coordinate system of a center point of the iris based on the ellipse equation of the imaged iris;

calculating an optical axis vector of the iris oriented in the three-axis coordinate system based on the center point of the iris and on the ellipse equation of the imaged iris;

projecting the optical axis vector into the user'"'"'s eyeball; and

determining a center point of the user'"'"'s eyeball by measuring one eyeball radius distance along the projected optical axis vector from the surface of the iris.

10. The method of claim 9, wherein calculating the optical axis vector for one of the eyes comprises:

determining coordinates in the three-dimensional coordinate system of at least two points on an edge of the imaged iris using the ellipse equation characterizing the imaged iris;

calculating an iris disc vector based on the center point of the iris disc and the first and second points of the iris edge;

calculating an optical axis vector of the iris oriented in the three-axis coordinate system based on the iris disc vector; and

projecting the optical axis vector into the eyeball.

11. A method of verifying a user'"'"'s identity using a computing device, comprising:

determining three-dimensional locations of an eyeball center point for each of the user'"'"'s eyes based upon locations of iris disc center points of the user'"'"'s eyes obtained from a digital image;

calculating an iris section line of the iris for the user'"'"'s eye based on the determined eyeball center points;

creating an iris contour map from the iris section line; and

comparing the iris contour map to biometric information stored in the computing device, wherein the stored biometric information comprises iris contour map data for at least one authorized user.

12. A computing device, comprising:

a digital camera; and

a processor coupled to the camera and configured with processor-executable instructions to perform operations comprising;

obtaining a digital image of a face of a user of the computing device with the digital camera;

processing the digital image to determine a position and orientation of an anatomical structure of the user that is beneath a surface of the user'"'"'s skin; and

translating the position determined and the orientation of the anatomical structure into an input command.

13. The computing device of claim 12, wherein the processor is configured with processor-executable instructions to perform operations such that processing the obtained image to determine a position and orientation of the anatomical structure of the user that is beneath a surface of the user'"'"'s skin comprises determining a spherical center location of at least one of the user'"'"'s eyeballs.

14. The computing device of claim 13, wherein the processor is configured with processor-executable instructions to perform operations such that determining a spherical center point location of a user'"'"'s eyeball comprises:

performing a least squares fit of iris-to-sclera boundary pixels in the digital image to determine an ellipse equation characterizing the imaged iris;

determining coordinates in a three-dimensional coordinate system of the center point of the iris based on the ellipse equation of the imaged iris;

calculating an optical axis vector of the iris oriented in the three-axis coordinate system based on the center point of the iris and on the ellipse equation of the imaged iris;

projecting the optical axis vector into the user'"'"'s eyeball; and

determining a center point of the user'"'"'s eyeball by measuring one eyeball radius distance along the projected optical axis vector from the surface of the iris.

15. The computing device of claim 14, wherein the processor is configured with processor-executable instructions to perform operations further comprising:

repeating operations to determine a center point for both eyeballs; and

determining an orientation of the user'"'"'s head within the digital image based the determined eyeball center points and an inter-eyeball distance between the determined eyeball center points.

16. A computing device, comprising:

a digital camera; and

a processor coupled to the camera and configured with processor-executable instructions to perform operations comprising;

prompting a user to look in a first direction;

obtaining a first digital image of the user'"'"'s face with the digital camera;

calculating a first optical axis vector for an eye based on the first digital image;

prompting the user to look in a second direction;

obtaining a second digital image of the user'"'"'s face;

calculating a second optical axis vector for an eye based on the second digital image based on the obtained image;

determining an intersection point of the first and second optical axis vectors; and

calculating the radius of the eyeball as a distance between the determined intersection point of the first and second optical axis vectors and a surface of the eyeball.

17. A computing device for implementing a user input on a graphical user interface, comprising:

a digital camera;

a display screen; and

a processor coupled to the digital camera and display, wherein the processor is configured with processor-executable instructions to perform operations comprising;

displaying a user interface feature on the graphical user interface presented on the display screen;

obtaining a digital image of a user'"'"'s eyes using the digital camera;

determining a location of an eyeball center point for each of the user'"'"'s eyes based on the determined location of an eyeball center point for each of the user'"'"'s eyes;

calculating an optical axis vector for each of the user'"'"'s eyes;

calculating a first visual axis for one of the user'"'"'s eyes and a second visual axis for the other of the user'"'"'s eyes based on the eyeball center points and the optical axes vectors;

determining the user'"'"'s point-of-gaze on the display screen, wherein the point-of-gaze comprises a point of intersection of the first and second visual axes; and

selecting the user interface feature on the graphical user interface when the user'"'"'s point-of-gaze is stationary for a predetermined duration of time.

18. The computing device of claim 17, wherein the processor is configured with processor-executable instructions to perform operations such that calculating the first visual axis and the second visual axis each comprises:

calculating an eyeball centers line between the eyeball center points based on the determined location of an eyeball center point for each of the user'"'"'s eyes;

calculating an eyeball centers extension line by laterally extending the eyeball centers line by an offset distance past the eyeball center point of the one of the user'"'"'s eyes; and

calculating a visual axis as a line between an origin point of the optical axis vector and an endpoint of eyeball centers extension line, wherein the endpoint of the eyeball centers extension line is ipsilateral to the one of the user'"'"'s eyes.

19. The computing device of claim 18, wherein the processor is configured with processor-executable instructions to perform operations such that the offset distance is determined by:

prompting a user to look at a gaze target presented on the display screen at a known position;

calculating an instantaneous visual axis of the one of the user'"'"'s eyes, wherein the instantaneous visual axis intersects the gaze target and the origin point of the optical axis vector;

calculating an intersection point of the instantaneous visual axis and the eyeball centers extension line; and

measuring a distance between an eyeball center point and the intersection point, wherein the eyeball center point is ipsilateral to the one of the user'"'"'s eyes.

20. The computing device of claim 17, wherein the processor is configured with processor-executable instructions to perform operations such that determining the location of an eyeball center point for each of the user'"'"'s eyes comprises:

performing a least squares fit of the iris-to-sclera boundary pixels in the digital image to determine an ellipse equation characterizing the imaged iris;

determining coordinates in a three-dimensional coordinate system of a center point of the iris based on the ellipse equation of the imaged iris;

calculating an optical axis vector of the iris oriented in the three-axis coordinate system based on the center point of the iris and on the ellipse equation of the imaged iris;

projecting the optical axis vector into the user'"'"'s eyeball; and

determining a center point of the user'"'"'s eyeball by measuring one eyeball radius distance along the projected optical axis vector from the surface of the iris.

21. The computing device of claim 20, wherein the processor is configured with processor-executable instructions to perform operations such that calculating the optical axis vector for one of the eyes comprises:

determining coordinates in the three-dimensional coordinate system of at least two points on an edge of the imaged iris using the ellipse equation characterizing the imaged iris;

calculating an iris disc vector based on the center point of the iris disc and the first and second points of the iris edge;

calculating an optical axis vector of the iris oriented in the three-axis coordinate system based on the iris disc vector; and

projecting the optical axis vector into the eyeball.

22. A computing device configured to verify a user'"'"'s identity, comprising:

a digital camera; and

a processor coupled to the display, wherein the processor is configured with processor-executable instructions to perform operations comprising;

determining three-dimensional locations of an eyeball center point for each of the user'"'"'s eyes based upon locations of iris disc center points of the user'"'"'s eyes obtained from a digital image;

calculating an iris section line of the iris for the user'"'"'s eye based on the determined eyeball center points;

creating an iris contour map from the iris section line; and

comparing the iris contour map to biometric information stored in the computing device, wherein the stored biometric information comprises iris contour map data for at least one authorized user.

23. A computing device, comprising:

means for obtaining a digital image of a face of a user of the computing device;

means for processing the digital image to determine a position and orientation of an anatomical structure of the user that is beneath a surface of the user'"'"'s skin; and

means for translating the position determined and the orientation of the anatomical structure into an input command.

24. The computing device of claim 23, wherein means for processing the obtained image to determine a position and orientation of the anatomical structure of the user that is beneath a surface of the user'"'"'s skin comprises means for determining a spherical center location of at least one of the user'"'"'s eyeballs.

25. The computing device of claim 24, wherein means for determining a spherical center point location of a user'"'"'s eyeball comprises:

means for performing a least squares fit iris-to-sclera boundary pixels in the digital image to determine an ellipse equation characterizing the imaged iris;

means for determining coordinates in a three-dimensional coordinate system of the center point of the iris based on the ellipse equation of the imaged iris;

means for calculating an optical axis vector of the iris oriented in the three-axis coordinate system based on the center point of the iris and on the ellipse equation of the imaged iris;

means for projecting the optical axis vector into the user'"'"'s eyeball; and

means for determining a center point of the user'"'"'s eyeball by measuring one eyeball radius distance along the projected optical axis vector from the surface of the iris.

26. The computing device of claim 25, further comprising:

means for repeating operations to determine a center point for both eyeballs; and

means for determining an orientation of the user'"'"'s head within the digital image based the determined eyeball center points and an inter-eyeball distance between the determined eyeball center points.

27. A computing device, comprising:

means for prompting a user to look in a first direction;

means for obtaining a first digital image of the user'"'"'s face;

means for calculating a first optical axis vector for an eye based on the first digital image;

means for prompting the user to look in a second direction;

means for obtaining a second digital image of the user'"'"'s face;

calculating a second optical axis vector for an eye based on the second digital image based on the obtained image;

means for determining an intersection point of the first and second optical axis vectors; and

means for calculating the radius of the eyeball as a distance between the determined intersection point of the first and second optical axis vectors and a surface of the eyeball.

28. A computing device for implementing a user input on a graphical user interface, comprising:

means for displaying a clickable feature on a display screen;

means for obtaining a digital image of a user'"'"'s eyes;

means for determining a location of an eyeball center point for each of the user'"'"'s eyes based on the determined location of an eyeball center point for each of the user'"'"'s eyes;

means for calculating an optical axis vector for each of the user'"'"'s eyes;

means for calculating a first visual axis for one of the user'"'"'s eyes and a second visual axis for the other of the user'"'"'s eyes based on the eyeball center points and the optical axes vectors;

means for determining the user'"'"'s point-of-gaze on the display screen, wherein the point-of-gaze comprises a point of intersection of the first and second visual axes; and

means for selecting the user interface feature on the graphical user interface when the user'"'"'s point-of-gaze is stationary for a predetermined duration of time.

29. The computing device of claim 28, wherein means for calculating the first visual axis and the second visual axis each comprises:

means for calculating an eyeball centers line between the eyeball center points based on the determined location of an eyeball center point for each of the user'"'"'s eyes;

means for calculating an eyeball centers extension line by laterally extending the eyeball centers line by an offset distance past the eyeball center point of the one of the user'"'"'s eyes; and

means for calculating a visual axis as a line between an origin point of the optical axis vector and an endpoint of eyeball centers extension line, wherein the endpoint of the eyeball centers extension line is ipsilateral to the one of the user'"'"'s eyes.

30. The computing device of claim 29, further comprising means for determining the offset distance comprising:

means for prompting a user to look at a gaze target presented on the display screen at a known position;

means for calculating an instantaneous visual axis of the one of the user'"'"'s eyes, wherein the instantaneous visual axis intersects the gaze target and the origin point of the optical axis vector;

means for calculating an intersection point of the instantaneous visual axis and the eyeball centers extension line; and

means for measuring a distance between an eyeball center point and the intersection point, wherein the eyeball center point is ipsilateral to the one of the user'"'"'s eyes.

31. The computing device of claim 30, wherein means for determining the location of an eyeball center point for each of the user'"'"'s eyes comprises:

means for performing a least squares fit of the iris-to-sclera boundary pixels in the digital image to determine an ellipse equation characterizing the imaged iris;

means for determining coordinates in a three-dimensional coordinate system of a center point of the iris based on the ellipse equation of the imaged iris;

means for calculating an optical axis vector of the iris oriented in the three-axis coordinate system based on the center point of the iris and on the ellipse equation of the imaged iris;

means for projecting the optical axis vector into the user'"'"'s eyeball; and

means for determining a center point of the user'"'"'s eyeball by measuring one eyeball radius distance along the projected optical axis vector from the surface of the iris.

32. The computing device of claim 31, wherein means for calculating the optical axis vector for one of the eyes comprises:

means for determining coordinates in the three-dimensional coordinate system of at least two points on an edge of the imaged iris using the ellipse equation characterizing the imaged iris;

means for calculating an iris disc vector based on the center point of the iris disc and the first and second points of the iris edge;

means for calculating an optical axis vector of the iris oriented in the three-axis coordinate system based on the iris disc vector; and

means for projecting the optical axis vector into the eyeball.

33. A computing device configured to verify a user'"'"'s identity, comprising:

means for determining three-dimensional locations of an iris disc center point for each of the user'"'"'s eyes based upon locations of iris disc center points of the user'"'"'s eyes obtained from a digital image;

means for determining a three-dimensional location of an eyeball center point for each of the user'"'"'s eyes based on the determined eyeball center points;

means for calculating an iris section line of the iris for the user'"'"'s eye;

means for creating an iris contour map from the iris section line; and

means for comparing the iris contour map to biometric information stored in the computing device, wherein the stored biometric information comprises iris contour map data for at least one authorized user.

34. A non-transitory processor-readable storage medium having stored thereon processor-executable instructions configured to cause a processor of a computing device including a digital camera to perform operations comprising:

obtaining a digital image of a face of a user of the non-transitory processor-readable storage medium with the digital camera;

processing the digital image to determine a position and orientation of an anatomical structure of the user that is beneath a surface of the user'"'"'s skin; and

translating the position determined and the orientation of the anatomical structure into an input command.

35. The non-transitory processor-readable storage medium of claim 34, wherein the stored processor-executable instructions are configured to cause the processor to perform operations such that processing the obtained image to determine a position and orientation of the anatomical structure of the user that is beneath a surface of the user'"'"'s skin comprises determining a spherical center location of at least one of the user'"'"'s eyeballs.

36. The non-transitory processor-readable storage medium of claim 35, wherein the stored processor-executable instructions are configured to cause the processor to perform operations such that determining a spherical center point location of a user'"'"'s eyeball comprises:

performing a least squares fit of iris-to-sclera boundary pixels in the digital image to determine an ellipse equation characterizing the imaged iris;

determining coordinates in a three-dimensional coordinate system of the center point of the iris based on the ellipse equation of the imaged iris;

calculating an iris disc vector, wherein the iris disc vector is a cross product of a vector from the center point of the iris disc to a first point on the iris edge, and a vector from the center point of the iris disc to a second point of the iris edge;

calculating an optical axis vector of the iris oriented in the three-axis coordinate system based on the center point of the iris and on the ellipse equation of the imaged iris;

projecting the optical axis vector into the user'"'"'s eyeball; and

determining a center point of the user'"'"'s eyeball by measuring one eyeball radius distance along the projected optical axis vector from the surface of the iris.

37. The non-transitory processor-readable storage medium of claim 36, wherein the stored processor-executable instructions are configured to cause the processor to perform operations further comprising:

repeating operations to determine a center point for both eyeballs; and

determining an orientation of the user'"'"'s head within the digital image based the determined eyeball center points and an inter-eyeball distance between the determined eyeball center points.

38. A non-transitory processor-readable storage medium having stored thereon processor-executable instructions configured to cause a processor of a computing device including a digital camera to perform operations comprising:

prompting a user to look in a first direction;

obtaining a first digital image of the user'"'"'s face with the digital camera;

calculating a first optical axis vector for an eye based on the first digital image;

prompting the user to look in a second direction;

obtaining a second digital image of the user'"'"'s face;

calculating a second optical axis vector for an eye based on the second digital image based on the obtained image;

determining an intersection point of the first and second optical axis vectors; and

calculating the radius of the eyeball as a distance between the determined intersection point of the first and second optical axis vectors and a surface of the eyeball.

39. A non-transitory processor-readable storage medium having stored thereon processor-executable instructions configured to cause a processor of a computing device including a digital camera and a display screen to perform operations comprising:

displaying a user interface feature on a graphical user interface presented on the display screen;

obtaining a digital image of a user'"'"'s eyes using the digital camera;

determining a location of an eyeball center point for each of the user'"'"'s eyes based on the determined location of an eyeball center point for each of the user'"'"'s eyes;

calculating an optical axis vector for each of the user'"'"'s eyes;

calculating a first visual axis for one of the user'"'"'s eyes and a second visual axis for the other of the user'"'"'s eyes based on the eyeball center points and the optical axes vectors;

determining the user'"'"'s point-of-gaze on the display screen, wherein the point-of-gaze comprises a point of intersection of the first and second visual axes; and

selecting the user interface feature on the graphical user interface when the user'"'"'s point-of-gaze is stationary for a predetermined duration of time.

40. The non-transitory processor-readable storage medium of claim 39, wherein the stored processor-executable instructions are configured to cause the processor to perform operations such that calculating the first visual axis and the second visual axis each comprises:

calculating an eyeball centers line between the eyeball center points based on the determined location of an eyeball center point for each of the user'"'"'s eyes;

calculating an eyeball centers extension line by laterally extending the eyeball centers line by an offset distance past the eyeball center point of the one of the user'"'"'s eyes; and

calculating a visual axis as a line between an origin point of the optical axis vector and an endpoint of eyeball centers extension line, wherein the endpoint of the eyeball centers extension line is ipsilateral to the one of the user'"'"'s eyes.

41. The non-transitory processor-readable storage medium of claim 40, wherein the stored processor-executable instructions are configured to cause the processor to perform operations such that the offset distance is determined by:

prompting a user to look at a gaze target presented on the display screen at a known position;

calculating an instantaneous visual axis of the one of the user'"'"'s eyes, wherein the instantaneous visual axis intersects the gaze target and the origin point of the optical axis vector;

calculating an intersection point of the instantaneous visual axis and the eyeball centers extension line; and

measuring a distance between an eyeball center point and the intersection point, wherein the eyeball center point is ipsilateral to the one of the user'"'"'s eyes.

42. The non-transitory processor-readable storage medium of claim 39, wherein the stored processor-executable instructions are configured to cause the processor to perform operations such that determining the location of an eyeball center point for each of the user'"'"'s eyes comprises:

performing a least squares fit of the iris-to-sclera boundary pixels in the digital image to determine an ellipse equation characterizing the imaged iris;

determining coordinates in a three-dimensional coordinate system of a center point of the iris based on the ellipse equation of the imaged iris;

calculating an optical axis vector of the iris oriented in the three-axis coordinate system based on the center point of the iris and on the ellipse equation of the imaged iris;

projecting the optical axis vector into the user'"'"'s eyeball; and

determining a center point of the user'"'"'s eyeball by measuring one eyeball radius distance along the projected optical axis vector from the surface of the iris.

43. The non-transitory processor-readable storage medium of claim 42, wherein the stored processor-executable instructions are configured to cause the processor to perform operations such that calculating the optical axis vector for one of the eyes comprises:

determining coordinates in the three-dimensional coordinate system of at least two points on an edge of the imaged iris using the ellipse equation characterizing the imaged iris;

calculating an iris disc vectorbased on the center point of the iris disc and the first and second points of the iris edge;

calculating an optical axis vector of the iris oriented in the three-axis coordinate system based on the iris disc vector; and

projecting the optical axis vector into the eyeball.

44. A non-transitory processor-readable storage medium having stored thereon processor-executable instructions configured to cause a processor of a computing device including a digital camera to perform operations comprising:

determining a three-dimensional location of an eyeball center point for each of the user'"'"'s eyes based upon locations of iris disc center points of the user'"'"'s eyes obtained from a digital image;

calculating an iris section line of the iris for the user'"'"'s eye based on the determined eyeball center points;

creating an iris contour map from the iris section line; and

comparing the iris contour map to biometric information stored in the non-transitory processor-readable storage medium, wherein the stored biometric information comprises iris contour map data for at least one authorized user.