US 11,740,695 B2
Eye tracking system for use in head-mounted display units
Piotr Krukowski, Toruń (PL); Michal Meina, Toruń (PL); and Piotr Redmerski, Lipno (PL)
Assigned to Inseye Inc., Beacon, NY (US)
Filed by Inseye LLC, Lincolnshire, IL (US)
Filed on Aug. 11, 2021, as Appl. No. 17/399,967.
Claims priority of provisional application 63/064,078, filed on Aug. 11, 2020.
Prior Publication US 2022/0050522 A1, Feb. 17, 2022
Int. Cl. G06F 3/01 (2006.01); G01B 11/14 (2006.01); G01B 11/00 (2006.01)
CPC G06F 3/013 (2013.01) [G01B 11/002 (2013.01); G01B 11/14 (2013.01)] 18 Claims
OG exemplary drawing
 
1. An eye tracking system for use with a head-mounted display (HMD) unit, comprising:
a support frame mounted to the HMD unit;
a light source mounted to the support frame and configured to illuminate an area of a subject's eye;
a plurality of photosensors mounted to the support frame and configured to receive reflected light from different portions of the illuminated eye;
a temperature sensor mounted to the support frame and configured to measure an interior temperature of the HMD unit; and
a processor programmed to execute an algorithm including:
a processing module that compensates photosensor measurement error due to variable operating temperature in the HMD unit including:
receiving the interior temperature measurement of the HMD unit from the temperature sensor;
determining an estimated temperature of the photosensors based on the received interior temperature measurement of the HMD unit and a coefficient based on the HMD unit; and
compensating photosensor measurement error based on the estimated temperature of the photosensors by calculating a heat transfer formula including:
Tph(i)=Tph(i−i)+K·(T(i−1)−T(i));
wherein Tph(i) is an estimated photosensor temperature, T(i) is a measured interior temperature of the HMD unit, and K is a heat transfer coefficient; and
an eye-tracking module that determines a gaze position of the eye using a mapping between intensities of photosensors and a gaze position estimated during a calibration procedure.