Eye tracking apparatus and method employing grayscale threshold values
First Claim
1. A system for determining a point of regard, said system comprising:
- camera means for acquiring a video image of a first vision means, said first vision means comprising a pupil, a position of said pupil corresponding to said point of regard, and said video image comprising a pupil image;
frame grabber means, coupled to said camera means, for accepting video data corresponding to said video image from said camera means and converting said video data to digital pixel data of a given dynamic range so as to provide said digital pixel data as a grayscale mapping of the video image;
computer means, coupled to said frame grabber means, for processing said digital pixel data to substantially determine the position of said pupil wherein said computer means includes;
memory means for providing an expected area value for the area of said pupil within said video image;
means for determining a grayscale threshold value in accordance with said expected area value and grayscale distribution of said digital pixel data;
means for segregating said digital pixel data into two separate binary groups as first and second groups using said grayscale threshold value as a discriminator; and
means for substantially determining the position of said pupil in accordance with the segregated data;
feedback means, coupled to said computer means, for accepting data corresponding to the determined position of said pupil from said computer means and feeding back to said first vision means feedback information representative of the determined position; and
support means, connected to said camera means and said feedback means, for fixing the relative physical positions of said camera means and said feedback means.
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Accused Products
Abstract
An eye-tracking system determines the position of a user'"'"'s pupil and maps this position into a point of regard of the user on an interface device, such as a display screen, or other real-world object by a system comprising a camera for acquiring a video image of the pupil; a frame grabber coupled to the camera for accepting and converting analog video data from the camera to digital pixel data; a computer coupled to the frame grabber for processing the digital pixel data to substantially determine the position of the pupil; a display screen coupled to the computer; and a support connected to the camera and display screen for fixing the relative physical positions thereof relative to the user'"'"'s pupil. The processing performed by the computer may include the selection of a first pixel intensity threshold for the segmentation of the digital pixel data into first and second groups, where the total pixel area of the first group is selected to be substantially equal to a pre-determined value expected to correspond to the area of a user'"'"'s pupil. The system may be calibrated by the user'"'"'s following a cursor on the display screen while the system measures the pupil position for known locations of the cursor.
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Citations
35 Claims
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1. A system for determining a point of regard, said system comprising:
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camera means for acquiring a video image of a first vision means, said first vision means comprising a pupil, a position of said pupil corresponding to said point of regard, and said video image comprising a pupil image; frame grabber means, coupled to said camera means, for accepting video data corresponding to said video image from said camera means and converting said video data to digital pixel data of a given dynamic range so as to provide said digital pixel data as a grayscale mapping of the video image; computer means, coupled to said frame grabber means, for processing said digital pixel data to substantially determine the position of said pupil wherein said computer means includes; memory means for providing an expected area value for the area of said pupil within said video image; means for determining a grayscale threshold value in accordance with said expected area value and grayscale distribution of said digital pixel data; means for segregating said digital pixel data into two separate binary groups as first and second groups using said grayscale threshold value as a discriminator; and means for substantially determining the position of said pupil in accordance with the segregated data; feedback means, coupled to said computer means, for accepting data corresponding to the determined position of said pupil from said computer means and feeding back to said first vision means feedback information representative of the determined position; and support means, connected to said camera means and said feedback means, for fixing the relative physical positions of said camera means and said feedback means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. An eye-tracking system for determining a point of regard on a display, said eye-tracking system comprising:
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a display screen providing said display and displaying information corresponding to said point of regard; a camera for acquiring a video image of an eye having a pupil, the position of said pupil corresponding to said point of regard, and said video image comprising a pupil image; a frame grabber, coupled to said camera, for accepting video data corresponding to said video image from said camera and converting said video data to digital pixel data of a given dynamic range so as to provide said digital pixel data as a grayscale mapping of said video image; a computer, coupled between said frame grabber and said display screen, for processing said digital pixel data to substantially determine said point of regard on said display screen wherein said computer includes; memory means for providing an expected area value for the area of said pupil within said video image; means for determining a grayscale threshold value in accordance with said expected area value and grayscale distribution of said digital pixel data; means for segregating said digital pixel data into two separate binary groups as first and second groups using said grayscale threshold value as a discriminator; and means for substantially determining the position of said pupil in accordance with the segregated data; and a support, connected to said camera and said display screen, for substantially fixing the physical positions of said camera means and said display screen relative to said eye. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. In a vision-tracking system, a tracking method for determining a point of regard, said method comprising the steps of:
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acquiring video data from a camera corresponding to a video image of a vision means, said vision means comprising a pupil, the position of said pupil corresponding to said point of regard, and said video image comprising a pupil image; converting said video data to digital pixel data corresponding to said video image using an analog-to-digital interface coupled to said camera so as to provide said digital pixel data of a given dynamic range as a grayscale mapping of said video image; providing an expected area value for said pupil; determining a grayscale threshold value in accordance with said expected area value and grayscale distribution of said digital pixel data; segregating said digital pixel data into first and second groups using said grayscale threshold value as a discriminator; determining the position of said pupil in accordance with the segregated data of one of said first group or said second group; and providing feedback data corresponding to said pupil position from said computer. - View Dependent Claims (30, 31, 32, 33, 34, 35)
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Specification