Abstract: Systems, methods, and computer programs for eye tracking. In one embodiment, a system includes a head-mounted device that takes measurements indicative of positions of an eye of a user (“eye positions”). The system also includes a head-mounted camera that captures images of the eye. A computer calculates the eye positions based on the measurements. The head-mounted camera is better positioned to capture images of the user's pupil when the eye positions fall within a certain range compared to when the eye positions fall outside the certain range. The computer calculates, at a first average rate, pupil features based on images captured when the eye positions fall within the certain range. The computer refrains from calculating pupil features, or calculates pupil features at a second average rate, which is less than half the first average rate, based on images captured when the eye positions fall outside the certain range.

Abstract: Systems, methods, and computer programs for efficient use of head-mounted cameras in eye tracking. In one embodiment, a system includes a head-mounted device that takes measurements indicative of positions of an eye of a user, and a head-mounted camera that captures images of the eye. A first range of eye positions trackable from the images is narrower than a second range of eye positions trackable from the measurements. A computer calculates the eye positions based on the measurements. When the eye positions fall within the first range, the computer reads images at a first bitrate from the head-mounted camera. And when the eye positions fall outside the first range, the computer refrains from reading images from the head-mounted camera, or reads the images from the head-mounted camera at a second bitrate that is less than half the first bitrate.

Abstract: Utilization of windowing to set a region of interest (ROI) of a camera used for tracking facial expressions. In one embodiment, a system includes an inward-facing head-mounted camera that captures images of a region on a user's head utilizing a sensor that supports changing of its ROI. The system also includes a computer that detects, in a first subset of the images, a first sub-region in which changes due to a first facial movement reach a first threshold and reads from the camera a first ROI that covers at least a portion of the first sub-region. The computer detects, in a second subset of the images, a second sub-region in which changes due to a second facial movement reach a second threshold, and then reads from the camera a second ROI that covers at least a portion of the second sub-region, with the first and second ROIs being different.

Abstract: System and method that utilize windowing for efficient capturing of facial landmarks include an inward-facing head-mounted camera that captures images of a region on a user's face utilizing a sensor supporting changing of its region of interest (ROI). The system also includes a computer that detects, based on the images, a type of facial expression expressed by the user, which belongs to a group comprising first and second facial expressions. Responsive to detecting that the user expresses the first facial expression, the computer reads from the camera a first ROI that covers a first subset of facial landmarks relevant to the first facial expression. Responsive to detecting that the user expresses the second facial expression, the computer reads from the camera a second ROI that covers a second subset of facial landmarks relevant to the second facial expression, with the first and second ROIs being different.

Abstract: Disclosed herein are systems and methods for tracking facial expressions efficiently. In one embodiment, a system includes a non-contact head-mounted electro-optical sensor (e.g., an inward-facing head-mounted camera), which measures reflections from a region on a user's head, which are indicative of facial expressions of the user. The system also includes a computer that detects, based on the reflections, a type of facial expression expressed by the user, which belongs to a group comprising neutral facial expressions and non-neutral facial expressions. The computer uses this detection to determine how to proceed to read the electro-optical sensor: the computer reads the electro-optical sensor at a first average bitrate (b1) when the user expresses a facial expression from among the neutral facial expressions, and reads the electro-optical sensor at a second average bitrate (b2) when the user expresses a facial expression from among the non-neutral facial expressions, where b2>b1.

Abstract: The present disclosure pertains to head-mounted dual-sided photoplethysmography (PPG) systems and methods for blood flow measurement. In one embodiment, a system comprises a frame designed to be worn on a user's head, integrating a first PPG device positioned on the first side of the user's nose and a second PPG device on the opposite side. Each PPG device includes a light source and photodetector, enabling the capture of optical signals indicative of blood flow within the nasal tissue. A computer is operatively connected to both PPG devices, responsible for obtaining first and second signals from each side and processing these signals to calculate comprehensive measurements of the user's blood flow. This dual-sided configuration enhances measurement accuracy and reliability by mitigating motion artifacts and improving signal quality compared to traditional single-sided PPG systems.

Abstract: Due to the many interactions that can occur in places of gatherings, such as workplaces, schools, theaters, etc., these locations can be considered dangerous to enter during times of epidemics. It is difficult to keep track of the health state of all the people who visited a location, and thus ascertain if visits to the location pose any risk of contracting a disease. Some embodiments disclosed herein utilize wearable devices that measure physiological signals of their wearer in order to determine whether people who were at a location were healthy, and thus be able to certify the location as contagion-safe.

Abstract: Systems, methods, and computer programs for eye tracking involving a camera that is operated according to eyelid position. In one embodiment, an inward-facing head-mounted camera captures images of an eye. A head-mounted device emits electromagnetic waves towards the eye and measures reflections of these waves from the eye. The average rate of reflection measurements is at least ten times the average rate of image capture. A computer detects the position of at least one of the eyelids covering the eye based on the reflection measurements. And the camera operation is adjusted according to the eyelid position in a manner that decreases, in the captured images, areas depicting the eyelids, and optionally increases areas depicting the iris.

Abstract: Systems, methods, and computer programs for eye tracking. In one embodiment, an eye tracking system includes a head-mounted device that takes measurements indicative of a position of the eye of a user. A head-mounted camera captures an image of the eye. A computer calculates the position of the eye based on the measurements, utilizes the position of the eye to crop the image around the pupil, and provides a cropped image to a video-based eye tracker. Optionally, the size of the cropped image is less than a third of the size of its respective uncropped image. Optionally, the head-mounted device includes one or more of the following: a photosensor-oculography device (PSOG), an electrooculography device (EOG), an electromyography device (EMG), an optical flow sensor, and a range sensor. Optionally, the image-based eye tracker calculates, based on the cropped image, at least one of pupil diameter and pupillary response.

Abstract: Disclosed herein is a doorway that facilitates passage from an inside to an outside, and which includes a barrier that moves between opened and closed positions based on commands sent by a computer. Sensors measure signals indicating whether a first user is on the outside, and whether a second user on the inside. The computer detects that the first user is on the outside and receives, from a device of the first user, an indication indicating the first user is healthy. The computer detects whether the second user is on the inside, and commands the barrier to move to the opened position if: (i) the second user is not on the inside, or (ii) the second user is on the inside and the computer receives, from a device of the second user, an indication indicating the second user is healthy.

Abstract: Embodiments disclosed herein utilize biometric verification from wearable devices to approve access for shared spaces. Requests to occupy the shared spaces are received and conditional reservations are made pending health checks of the requesters. Prior to occupation, fresh biometric measurements are captured via the user's wearable device, which include physiological signals validating both ongoing good health as well as identity match to the original requester. When recent biometric verification indicates both healthy status and unchanged identity, access to the reserved space is approved. These embodiments securely manage reservations while protecting the health of other occupants through conditional access related to the requester's current health condition.

Abstract: Disclosed herein are systems and methods for tracking facial expressions efficiently. In one embodiment, a system includes a non-contact head-mounted electro-optical sensor (e.g., an inward-facing head-mounted camera), which measures reflections from a region on a user's head, which are indicative of facial expressions of the user. The system also includes a computer that detects, based on the reflections, a type of facial expression expressed by the user, which belongs to a group comprising neutral facial expressions and non-neutral facial expressions. The computer uses this detection to determine how to proceed to read the electro-optical sensor: the computer reads the electro-optical sensor at a first average bitrate (b1) when the user expresses a facial expression from among the neutral facial expressions, and reads the electro-optical sensor at a second average bitrate (b2) when the user expresses a facial expression from among the non-neutral facial expressions, where b2>b1.

Abstract: System and method that utilize windowing for efficient capturing of facial landmarks include an inward-facing head-mounted camera that captures images of a region on a user's face utilizing a sensor supporting changing of its region of interest (ROI). The system also includes a computer that detects, based on the images, a type of facial expression expressed by the user, which belongs to a group comprising first and second facial expressions. Responsive to detecting that the user expresses the first facial expression, the computer reads from the camera a first ROI that covers a first subset of facial landmarks relevant to the first facial expression. Responsive to detecting that the user expresses the second facial expression, the computer reads from the camera a second ROI that covers a second subset of facial landmarks relevant to the second facial expression, with the first and second ROIs being different.

Abstract: Described herein are embodiments of systems and methods that utilize images of a user's face to detect alcohol intoxication. One embodiment of a system to detect alcohol intoxication includes first and second inward-facing head-mounted cameras that are located less than 5 cm from a user's face, are sensitive to wavelengths below 1050 nanometer, and are configured to capture images of respective first and second regions on the user's face. The system also includes a computer that calculates, based on baseline images captured with the cameras while the user was not intoxicated, a baseline pattern of hemoglobin concentrations at regions on the face. The computer also calculates, based on a current set of images captured with the cameras, a current pattern of hemoglobin concentrations at the regions, and detects whether the user is intoxicated based on a deviation of the current pattern from the baseline pattern.

Abstract: Disclosed herein is photosensor-based detection of facial landmarks that utilizes images in order to detect and account for sensor shifts. In one embodiment, a system that detects positions of facial landmarks includes a head-mounted device comprising: (i) light sources that emit light towards a first region on a user's face, and (ii) discrete photosensors, spread over more than 2 cm, which take measurements of reflections of the light from the first region. The system also includes a head-mounted camera that captures images of a second region on the face. A computer calculates, based on the images, values indicative of a location and/or orientation of the device relative to the face, and detects, based on the reflections and the values, positions of facial landmarks at an average rate higher than an average rate at which the images are captured.

Abstract: Embodiments disclosed herein utilize biometric verification from wearable devices to approve access for shared spaces. Requests to occupy the shared spaces are received and conditional reservations are made pending health checks of the requesters. Prior to occupation, fresh biometric measurements are captured via the user's wearable device, which include physiological signals validating both ongoing good health as well as identity match to the original requester. When recent biometric verification indicates both healthy status and unchanged identity, access to the reserved space is approved. These embodiments securely manage reservations while protecting the health of other occupants through conditional access related to the requester's current health condition.

Abstract: Embodiments disclosed herein involve a wearable-based system that can help determine in a privacy-preserving manner whether a user is healthy (and thus poses low risk of contagiousness), and use determinations of this nature to grant passage through a doorway. In one embodiment, a wearable device takes measurements of a user comprising a photoplethysmogram signal (PPG signal) and a temperature measurement. A computer calculates a health score based on a difference between baseline measurements of the user, measured one or more days earlier, and more current measurements of the user. Additionally, the computer calculates an extent of similarity between characteristics of the PPG signal in the current measurements and characteristics of the PPG signal in the baseline measurements. The computer authorizes the user's passage through the doorway responsive to the health score reaching a first threshold and the extent of the similarity reaching a second threshold.

Abstract: Systems, methods, and computer programs for efficient use of head-mounted cameras in eye tracking. In one embodiment, a system includes a head-mounted device that takes measurements indicative of positions of an eye of a user, and a head-mounted camera that captures images of the eye. A first range of eye positions trackable from the images is narrower than a second range of eye positions trackable from the measurements. A computer calculates the eye positions based on the measurements. When the eye positions fall within the first range, the computer reads images at a first bitrate from the head-mounted camera. And when the eye positions fall outside the first range, the computer refrains from reading images from the head-mounted camera, or reads the images from the head-mounted camera at a second bitrate that is less than half the first bitrate.

Abstract: Systems, methods, and computer programs for eye tracking involving a camera that is operated according to eyelid position. In one embodiment, an inward-facing head-mounted camera captures images of an eye. A head-mounted device emits electromagnetic waves towards the eye and measures reflections of these waves from the eye. The average rate of reflection measurements is at least ten times the average rate of image capture. A computer detects the position of at least one of the eyelids covering the eye based on the reflection measurements. And the camera operation is adjusted according to the eyelid position in a manner that decreases, in the captured images, areas depicting the eyelids, and optionally increases areas depicting the iris.

Abstract: Systems, methods, and computer programs for eye tracking. In one embodiment, an eye tracking system includes a head-mounted device that takes measurements indicative of a position of the eye of a user. A head-mounted camera captures an image of the eye. A computer calculates the position of the eye based on the measurements, utilizes the position of the eye to crop the image around the pupil, and provides a cropped image to a video-based eye tracker. Optionally, the size of the cropped image is less than a third of the size of its respective uncropped image. Optionally, the head-mounted device includes one or more of the following: a photosensor-oculography device (PSOG), an electrooculography device (EOG), an electromyography device (EMG), an optical flow sensor, and a range sensor. Optionally, the image-based eye tracker calculates, based on the cropped image, at least one of pupil diameter and pupillary response.