Determination of position of a head-mounted device on a user

Abstract

A method for determining if a head-mounted device for extended reality is correctly positioned and performing a position correction procedure if the head-mounted device is determined to be incorrectly positioned, including performing eye tracking by estimating, based on a first image of a first eye of a user, a position of a pupil in two dimensions. The method also includes determining whether the estimated position of the pupil of the first eye is within a predetermined allowable area in the first image. The method also includes, responsive to determining that the estimated position of the pupil of the first eye is inside the predetermined allowable area, that the head-mounted device is correctly positioned on the user, or, responsive to determining that the position of the pupil of the first eye is outside the predetermined allowable area, that the head-mounted device is incorrectly positioned on the user.

What is claimed is: 
     
         1 . A method for determining if a head-mounted device is correctly positioned on a user, the method comprising:
 performing eye tracking based on an image of a first eye of the user, by determining what the first eye is tracking or gazing towards,
 determining that the estimated position of the pupil of the first eye is within a predetermined allowable area in the first image or is outside the predetermined allowable area in the first image; and further comprising: (A) responsive to determining that the estimated position of the pupil of the first eye is inside the predetermined allowable area of the first image, that the head-mounted device is correctly positioned on the user, or 
 (B) responsive to determining that the estimated position of the pupil of the first eye is outside the predetermined allowable area of the first image, that the head-mounted device is incorrectly positioned on the user. 
   
     
     
         2 . The method of  claim 1 , wherein the step of determining, using the processing circuitry, that the head-mounted device is correctly positioned on the user, further comprises:
 obtaining a gaze angle for the first eye;   comparing the obtained gaze angle to a preset gaze angle threshold value; and   performing one of:
 (a) if the obtained gaze angle is below the preset gaze angle threshold value, performing eye tracking and determining that the head-mounted device is correctly positioned on the user; or 
 (b) if the obtained gaze angle is not below the preset gaze angle threshold value, obtaining the gaze angle for the first eye. 
   
     
     
         3 . The method of  claim 1 , wherein the step of determining that the estimated position of the pupil of the first eye is within the predetermined allowable area in the first image or is outside the predetermined allowable area in the first image further comprises:
 estimating a center of a first pupil of the user.   
     
     
         4 . The method of  claim 1 , wherein the step of performing eye tracking, using processing circuitry, further comprises:
 obtaining an eye rotation center for the first eye, wherein the eye rotation center defines a point where all gaze directions of the first eye converge behind a cornea of the first eye; and   for a gaze direction, estimating a position of the pupil of the first eye in three dimensions, based on the obtained eye rotation center,   wherein the position of the pupil of the first eye, in two dimensions is estimated further based on the estimated position of the pupil of the first eye in three dimensions.   
     
     
         5 . The method of  claim 1 , further comprising:
 using the processing circuitry:
 performing eye tracking by estimating, based on a second image of a second eye of the user, the position of the pupil of the second eye in two dimensions, wherein each of the positions of the pupils of the first and second eyes, respectively, are defined according to a common coordinate system; and 
 determining an eye separation distance comprising a difference between a position of the pupil of the first eye and a position of the pupil of the second eye, 
   wherein determining that the head-mounted device is incorrectly positioned on the user is performed further responsive to determining that an absolute value of the determined eye separation distance is above a preset eye separation threshold value.   
     
     
         6 . The method of  claim 1 , further comprising:
 estimating a lens cup separation distance comprising a difference between a position of a center of a first lens cup of the head-mounted device and a position of a center of a second lens cup of the head-mounted device in three dimensions;   performing eye tracking by estimating an eye separation distance comprising a difference between a position of the pupil of the first eye of the user and a position of a pupil of a second eye of the user, in three dimensions, wherein each of the position of the center of the first lens cup and the position of the center of the second lens cup, respectively, and each of the pupil of the first eye of the user and the pupil of the second eye of the user, respectively, are defined according to a common coordinate system; and   calculating a difference between the lens cup separation distance and the eye separation distance;   comparing, to a predefined difference threshold value, the calculated difference between the lens cup separation distance and the eye separation distance,   wherein determining that the head-mounted device is incorrectly positioned on the user is performed further responsive to determining that the calculated difference is above the preset difference threshold value.   
     
     
         7 . The method of  claim 1 , further comprising, responsive to determining that the head-mounted device is incorrectly positioned on the user, performing a position correction procedure. 
     
     
         8 . The method of  claim 7 , wherein performing the position correction procedure comprises performing a motorized position correction of the lens cup distance. 
     
     
         9 . The method of  claim 7 , wherein performing the position correction procedure comprises generating a notification about the determined incorrect position of the head-mounted device. 
     
     
         10 . The method of  claim 7 , wherein performing the position correction procedure comprises initiating a positioning guide, wherein the positioning guide provides instructions for manual correction of the position of the head-mounted device. 
     
     
         11 . A system for determining if a head-mounted device is correctly positioned on a user, the method comprising:
 performing eye tracking based on an image of a first eye of a user, wherein the eye tracking comprises determining towards what the first eye is tracking or gazing;   determining that the estimated position of the pupil of the first eye is inside a predetermined allowable area in the first image or that the estimation position of the pupil of the first eye is outside the predetermined allowable area in the first image; and further comprising:
 (A) responsive to determining that the estimated position of the pupil of the first eye is inside the predetermined allowable area of the first image, determining that the head-mounted device is correctly positioned on the user, or 
 (B) responsive to determining that the estimated position of the pupil of the first eye is outside the predetermined allowable area of the first image, determining that the head-mounted device is incorrectly positioned on the user. 
   
     
     
         12 . The system of  claim 11 , wherein the processing circuitry is further configured to:
 obtain a gaze angle for the first eye;   compare the obtained gaze angle to a preset gaze angle threshold value; and wherein the processing circuitry is further configured to:
 (a) determine, if the obtained gaze angle is below the preset gaze angle threshold value, that the head-mounted device is correctly positioned on the user and performing eye tracking; or 
 (b) if the obtained gaze angle is not below the preset gaze angle threshold value, obtaining a subsequent gaze angle for the first eye. 
   
     
     
         13 . The system of  claim 11 , wherein the processing circuitry is further configured to:
 estimate a center of a first pupil of the user.   
     
     
         14 . The system of  claim 11 , wherein the processing circuitry is further configured to:
 obtain an eye rotation center for the first eye, wherein the eye rotation center defines a point where all gaze directions of the first eye converge behind the cornea of the first eye; and   for a gaze direction, estimate a position of the pupil of the first eye in three dimensions, based on the obtained eye rotation center,   wherein estimating the position of the pupil of the first eye in two dimensions is further based on the estimated position of the pupil of the first eye in three dimensions.   
     
     
         15 . The method of  claim 11 , wherein the processing circuitry is further configured to:
 perform eye tracking comprising estimating, based on a second image of a second eye of the user, a position of the pupil of the second eye in two dimensions, wherein the position of the pupil of the first eye and the position of the pupil of the second eye, respectively, are defined according to a common coordinate system;   determine an eye separation distance comprising a difference between the position of the pupil of the first eye and the position of the pupil of the second eye,   wherein determining that the head-mounted device is incorrectly positioned on the user is further responsive to:
 determining that the absolute value of the determined eye separation distance is above a preset eye separation threshold value. 
   
     
     
         16 . The system of  claim 11 , wherein the processing circuitry is further configured to:
 estimate a lens cup separation distance comprising a difference between a position of a center of a first lens cup of the head-mounted device and a position of a center of a second lens cup of the head-mounted device in three dimensions;   perform eye tracking by estimating an eye separation distance comprising a difference between the position of the pupil of the first eye of the user and the position of a pupil of a second eye of the user, in three dimensions, wherein each of the position of the center of the first lens cup and the second lens cup, respectively, and each of the pupil of the first eye of the user and the pupil of the second eye of the user, respectively, are defined according to a common coordinate system; and   calculate a difference between the lens cup separation distance and the eye separation distance;   compare, to a predefined difference threshold value, the calculated difference between the lens cup separation distance and the eye separation distance,   wherein determining that the head-mounted device is incorrectly positioned on the user is further responsive to:
 determining that the calculated difference is above the predefined difference threshold value. 
   
     
     
         17 . The system of  claim 11 , wherein the processing circuitry is further configured to perform, responsive to determining that the head-mounted device is incorrectly positioned on the user, a position correction procedure. 
     
     
         18 . The system of  claim 11 , wherein the processing circuitry is further configured to perform a position correction procedure by a motorized position correction of the lens cup distance. 
     
     
         19 . The system of  claim 11 , further comprising a manual lens cup position adjuster. 
     
     
         20 . The system of  claim 11 , wherein the processing circuitry is further configured to generate a notification about the determined incorrect position of the head-mounted device. 
     
     
         21 . The system of  claim 11 , wherein the processing circuitry is further configured to initiate a positioning guide, wherein the positioning guide provides instructions for manual correction of the position of the head-mounted device. 
     
     
         22 . A non-transitory computer-readable storage medium storing instructions which, when executed by processing circuitry of a system, cause the system to perform operations comprising:
 performing eye tracking based on an image of a first eye of the user, by determining towards what the first eye is tracking or gazing; and   determining that the estimated position of the pupil of the first eye is within a predetermined allowable area in the first image or is outside the predetermined allowable area in the first image, the operations further comprising:
 (A) responsive to determining that the determined position of the pupil of the first eye is inside the predetermined allowable area of the first image, determining that the head-mounted device is correctly positioned on the user; or 
 (B) responsive to determining that the determined position of the pupil of the first eye is outside the predetermined allowable area of the first image, determining that the head-mounted device is incorrectly positioned on the user. 
   
     
     
         23 . The non-transitory computer-readable storage medium of  claim 22 , further storing instructions which, when executed by processing circuitry of a system, cause the system to perform, responsive to determining that the head-mounted device is incorrectly positioned on the user, a position correction procedure.