Optokinesys
The present system can measure eye gaze position and detect, in near real-time, smooth eye movements that are driven by a moving stimulus. Smooth movements that match the velocity of a moving stimulus provide evidence that the subject can see the moving stimulus. The present system can give real-time feedback to the user, for example in the form of music, contingent on the ability of the user to perform smooth velocity-matched eye movements. The present system can measure visual impairment and train visual ability both for rehabilitation and development purposes.
1. A system comprising:
a display screen;
a camera capable of capturing sequential images of an eye; and
at least one processor configured to:
display a visual stimulus moving from a first region on the display screen to a second region on the display screen;
acquire, via the camera, a sequence of images of an eye of a subject viewing the display screen;
determine, from the sequence of images acquired using the camera, a gaze positon signal corresponding to respective gaze positions of the eye in the sequence of images;
compute a velocity vector from the gaze position signal;
determine a stimulus-correlated gaze velocity estimate based on the velocity vector and a speed at which the visual stimulus moves from the first region to the second region;
calculate, based on the stimulus-correlated gaze velocity estimate, a smooth-movement score vector indicative of a movement relationship level between the gaze position signal and the visual stimulus moving from the first region to the second region; and
generate, responsive to the smooth-movement score vector being above a predetermined threshold, a notification as feedback while the visual stimulus is moved on the display screen.
2. The system of claim 1 , wherein the gaze position signal is a horizontal gaze position signal indicating a horizontal gaze position of the eye.
3. The system of claim 1 , the at least one processor configured to change a spatial frequency of the visual stimulus.
4. The system of claim 1 , the at least one processor configured to change a contrast of the visual stimulus.
5. The system of claim 1 , wherein the notification comprises an audible notification.
6. The system of claim 1 , the at least one processor configured to display a second visual stimulus from the first region to the second region, the second visual stimulus having a spatial frequency or a contrast different than the visual stimulus.
7. The system of claim 1 , wherein:
the display screen comprises a motor; and
the at least one processor is further configured to drive the motor at a predetermined speed to move the visual stimulus from the first region to the second region.
8. The system of claim 1 , wherein the visual stimulus is a physical visual stimulus.
9. A system comprising:
a display screen;
an eye-tracking monitor comprising a camera capable of capturing sequential images of an eye, and configured to (i) detect a gaze position of the eye in sequential images and (ii) generate a gaze position signal corresponding to the detected gaze position, wherein the gaze position signal comprises a plurality of samples; and
at least one processor configured to:
display a visual stimulus moving from a first region on the display screen to a second region on the display screen;
receive, from the eye-tracking monitor, the gaze position signal corresponding to gaze position detected as the visual stimulus moves from the first region to the second region on the display screen;
generate a count of the plurality of samples in each of a plurality of predetermined target velocity ranges;
calculate a smooth-movement score vector based on the count of the plurality of samples in each of the predetermined target velocity ranges, the smooth-movement score vector indicative of a movement relationship level between the gaze position signal and the visual stimulus moving from the first region to the second region; and
generate, responsive to the smooth-movement score vector being above a predetermined threshold, a notification as feedback while the visual stimulus is moved on the display screen.
10. A method implemented by a computer comprising at least one processor, the method comprising:
displaying, on a display screen, a visual stimulus moving from a first region on the display screen to a second region on the display screen;
generating, via an eye-tracking monitor comprising a camera capable of capturing sequential images of an eye, a gaze position signal corresponding to a gaze position of the eye detected in sequential images as the visual stimulus moves from the first region to the second region;
computing a velocity vector from the gaze position signal;
determining a stimulus-correlated gaze velocity estimate based on the velocity vector and a speed the visual stimulus moves from the first region to the second region;
calculating, based on the stimulus-correlated gaze velocity estimate, a smooth-movement score vector indicative of a movement relationship level between the gaze position signal and the visual stimulus moving from the first region to the second region; and
generating, responsive to the smooth-movement score vector being above a predetermined threshold, a notification as feedback while the visual stimulus is moved on the display screen.
11. The method of claim 10 , wherein the gaze position signal is a horizontal gaze position signal indicating a horizontal gaze position of the eye.
12. The method of claim 10 , further comprising changing a spatial frequency of the visual stimulus.
13. The method of claim 10 , further comprising changing a contrast of the visual stimulus.
14. The method of claim 10 , further comprising generating an audible notification.
15. The method of claim 10 , further comprising displaying a second visual stimulus from the first region to the second region, the second visual stimulus having a spatial frequency or a contrast different than the visual stimulus.
16. The method of claim 10 , further comprising driving a motor of the display screen at a predetermined speed to move the visual stimulus from the first region to the second region.
17. The method of claim 10 , wherein the visual stimulus is a physical visual stimulus.
18. A method implemented by a computer comprising at least one processor, the method comprising:
displaying, on a display screen, a visual stimulus moving from a first region on the display screen to a second region on the display screen;
generating, via an eye-tracking monitor comprising a camera capable of capturing sequential images of an eye, a gaze position signal corresponding to a gaze position of the eye detected in sequential images as the visual stimulus moves from the first region to the second region, the gaze position signal comprising a plurality of samples;
generating, from the gaze position signal, a count of the plurality of samples in each of a plurality of predetermined target velocity ranges;
calculating a smooth-movement score vector based on the count of the plurality of samples in each of the predetermined target velocity ranges, the smooth-movement score vector indicative of a movement relationship level between the gaze position signal and the visual stimulus moving from the first region to the second region; and
generating, responsive to the smooth-movement score vector being above a predetermined threshold, a notification as feedback while the visual stimulus is moved on the display screen.