US 12,347,173 B2
Eye openness
Clément Morin, Danderyd (SE); Joakim Zachrisson, Danderyd (SE); Jonas Sjöstrand, Danderyd (SE); Shanker Keshavdas, Danderyd (SE); and Ylva Björk, Danderyd (SE)
Assigned to Tobii AB, Danderyd (SE)
Filed by Tobii AB, Danderyd (SE)
Filed on Feb. 28, 2023, as Appl. No. 18/175,577.
Claims priority of application No. 2250299-1 (SE), filed on Mar. 4, 2022.
Prior Publication US 2023/0277089 A1, Sep. 7, 2023
Int. Cl. G06V 10/774 (2022.01); G06F 3/01 (2006.01); G06V 40/18 (2022.01)
CPC G06V 10/774 (2022.01) [G06F 3/013 (2013.01); G06V 40/193 (2022.01)] 19 Claims
OG exemplary drawing
 
1. A controller configured to:
receive first curve data defining a first curve representative of a first eyelid edge in an image of an eye;
receive second curve data defining a second curve representative of a second eyelid edge in the image of the eye;
determine an eye openness indicator line extending from a first intersection point on the first curve to a second intersection point on the second curve by performing an optimization routine comprising:
defining an objective function representative of:
an orthogonality of the eye openness indicator line to a first tangent to the first curve at the first intersection point; and
an orthogonality of the eye openness indicator line to a second tangent to the second curve at the second intersection point; and
adjusting a value of the first intersection point and a value of the second intersection point until at least one termination condition for a value of the objective function is satisfied, wherein the at least one termination condition comprises at least one of:
the value of the objective function is less than a threshold value;
the value of the objective function is greater than a threshold value;
a variation of a fixed number of successive values of the objective function converge within a convergence threshold; and
a maximum number of iterations of adjusting the value of the first intersection point and the value of the second intersection point have been performed; and
provide an eye openness value based on a length of the eye openness indicator line.