Tobii Ab

Mikael Rosell

Simon Johansson

Joakim Zachrisson

Pravin Kumar Rana

Yimu Wang

Johannes Kron

Gilfredo Remon Salazar

Mark Ryan

Macarena Garcia Romero

Carlos Pedreira

Daniel Wrang

The invention is related to a method and arrangement for calibrating the camera of an eye tracking device and compensate for a potential angular offset of the camera. The method comprises: the steps of capturing an eye image of a user, wherein the eye image contains a plurality of glints created by a plurality of illuminators in the eye tracking system; detecting glints in the eye image; projecting illuminator positions onto the eye image to determine expected glint positions; determining an angular offset between expected glint positions and detected glint positions for corresponding pairs of expected and detected glint positions; determining the angular correction for the eye tracking camera using the determined angular offset angle; and applying the angular correction for the eye tracking camera to an eye tracker camera model.

Dynamic camera rotation calibration

An eye tracking system comprises at least one illuminator and at least one image sensor configured to produce an image of an eye of a user, the image including illuminator light reflected from the eye of a user. A Fresnel lens is positioned between the image sensor and the eye of the user, through which the image sensor views the eye. Processing circuitry receives an image from the image sensor, identifies glints in the image, assigns an angular position to each glint based on an angular relationship between each glint and a centre of the Fresnel lens and determines how many glints have the same angular position. Glints are classified as false glints if more than a predetermined number of glints have the same angular position.

Method and system for glint classification

An eye tracking system configured to: receive a plurality of right eye images of a right eye of a user; receive a plurality of left eye images of a left eye of a user, each left eye image corresponding to a right eye image in the plurality of right eye images; detect a pupil and determine an associated pupil signal, for each of the plurality of right eye images and each of the plurality of left eye images; calculate a right eye pupil variation of the pupil signals for the plurality of right eye images and a left eye pupil variation of the pupil signals for the plurality of left eye images; and determine a right eye weighting and a left eye weighting based on the right eye pupil variation and the left eye pupil variation. For one or more right eye images and one or more corresponding left eye images, the eye tracking system can: determine at least one right eye gaze signal based on the right eye image and at least one left eye gaze signal based on the corresponding left eye image; and calculate a combined gaze signal from a weighted sum of the right eye gaze signal and the left eye gaze signal using the right eye weighting and the left eye weighting.

Eye gaze tracking system, associated methods and computer programs

An eye tracking system comprising a controller configured to receive a reference image of an eye of a user and a current image of the eye of the user. The controller is also configured to determine a difference between the reference image and the current image to define a differential image. The differential image has a two dimensional pixel array of pixel locations that are arranged in a plurality of rows and columns. Each pixel location has a differential intensity value. The controller is further configured to calculate a plurality of row values by combining the differential intensity values in corresponding rows of the differential image and to determine eyelid data based on the plurality of row values.

Eye tracking system

There is provided a method, system, and non-transitory computer-readable storage medium for classifying glints using an eye tracking system of a head-mounted device, by obtaining the position of any glint present in a current image of the first eye; obtaining a dataset indicative of the respective position of at least one glint detected in one or more previously captured images of the first eye; and, for each glint present in current image, determining if the position of the glint corresponds to the position of a glint in the dataset and, if the positions correspond, classify the glint as a static glint. The static glints may be excluded from further processing in the eye tracking system. If there has been a movement of an eye of the user of the head-mounted device, embodiments may further comprise updating the dataset based on the current image.

Classification of glints using an eye tracking system

An eye tracking system configured to: receive a plurality of right-eye-images of a right eye of a user; receive a plurality of left-eye-images of a left eye of a user, each left-eye-image corresponding to a right-eye-image in the plurality of right-eye-images; detect a pupil and determine an associated pupil-signal, for each of the plurality of right-eye-images and each of the plurality of left-eye-images; calculate a right-eye-pupil-variation of the pupil-signals for the plurality of right-eye-images and a left-eye-pupil-variation of the pupil-signals for the plurality of left-eye-images; and determine a right-eye-weighting and a left-eye-weighting based on the right-eye-pupil-variation and the left-eye-pupil-variation. For one or more right-eye-images and one or more corresponding left-eye-images, the eye tracking system can: determine at least one right-eye-gaze-signal based on the right-eye-image and at least one left-eye-gaze-signal based on the corresponding left-eye-image; and calculate a combined-gaze-signal from a weighted sum of the right-eye-gaze-signal and the left-eye-gaze-signal using the right-eye-weighting and the left-eye-weighting.

There is provided a method and system for determining if a head-mounted device for extended reality (XR) is correctly positioned on a user, and optionally performing a position correction procedure if the head-mounted device is determined to be incorrectly positioned on the user. Embodiments include: performing eye tracking by estimating, based on a first image of a first eye of the user, a position of a pupil in two dimensions; determining whether the estimated position of the pupil of the first eye is within a predetermined allowable area in the first image; and, if the determined position of the pupil of the first eye is inside the predetermined allowable area, concluding that the head-mounted device is correctly positioned on the user; or, if the determined position of the pupil of the first eye is outside the predetermined allowable area, concluding that the head-mounted device is incorrectly positioned on the user.

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

An eye-tracking system for performing a pupil-detection process, the eye-tracking system configured to: receive image-data comprising a plurality of pixel-arrays, each pixel-array having a plurality of pixel locations and an intensity-value at each of the pixel locations; for each pixel location of a region of pixel locations: define an intensity-value-set comprising the intensity-values at the pixel location for two or more of the plurality of pixel-arrays; and determine the pixel location to be an excluded pixel location if the intensity-value-set does not satisfy an intensity condition; and exclude the excluded pixel locations from the pupil-detection process.

Eye-tracking system and method for pupil detection, associated systems and computer programs

The present disclosure relates to a method for calibrating a camera of a head-mounted display, HMD. The method comprises providing a calibration target in front of a lens of the HMD. Each of the calibration target and the lens basically extend in a corresponding two-dimensional plane. The method further comprises determining a lateral position of the calibration target. The lateral position relates to a position of the calibration target in the two-dimensional plane. The method even further comprises determining a lateral position of the lens. The lateral position relates to a position of the lens in the two-dimensional plane. The method yet even further comprises determining a calibration target misalignment based on the determined lateral position of the calibration target and based on the determined lateral position of the lens. The method also comprises performing a hardware calibration of the HMD. The hardware calibration is adapted for the calibration target misalignment. The present disclosure also relates to an arrangement and a computer program product.

Growing community of inventors

Danderyd, Sweden

Mikael Rosell