Described herein are embodiments of systems and methods that utilize temperature measurements taken with head-mounted sensors as well as images of a user's face to detect fever and/or intoxication. One embodiment of a system to detect fever includes a first head-mounted temperature sensor that measures skin temperature (T.sub.skin) at a first region on a user's head, a second head-mounted temperature sensor that measures a temperature of the environment (T.sub.env), and a computer. The computer receives images of a second region on the user's face, captured by a camera sensitive to wavelengths below 1050 nanometer, and calculates, based on the images, values indicative of hemoglobin concentrations at three or more regions on the user's face. The computer can then detect whether the user has a fever based on T.sub.skin, T.sub.env and the values.

A method of monitoring a patient's foot forms a thermogram of the sole of at least one foot of the patient, and determines whether the thermogram presents at least one of a plurality of prescribed patterns. The method also compares the thermogram against a prior thermogram of the same foot, and produces output information indicating the emergence of an ulcer on a given portion on the at least one foot as a function of 1) whether the thermogram is determined to present the at least one pattern, and 2) the comparison with the prior thermogram, which shows non-ulcerated tissue at the given location.

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.

Systems and methods for detecting an occurrence of a transient ischemic attack (TIA). In one embodiment, a device is utilized to measure first and second signals indicative of photoplethysmogram signals at first and second regions on the left and right sides of a user's head (PPG.sub.SL and PPG.sub.SR, respectively). A computer detects the occurrence of a TIA based on PPG.sub.SL and PPG.sub.SR that exhibit a pattern that involves the following: (i) an asymmetry between PPG.sub.SL and PPG.sub.SR, which is below a threshold, during a first period spanning more than a day; (ii) an asymmetry between PPG.sub.SL and PPG.sub.SR, which exceeds the threshold, during a second period following the first period and spanning between 5 and 180 minutes; and (iii) an asymmetry between PPG.sub.SL and PPG.sub.SR, which falls below the threshold, during a third period following the second period.

An in-vivo temperature measurement device includes a plurality of thermal resistors, temperature sensors for measuring an epidermis temperature of a living body, and temperature sensors for measuring an upper surface temperature that are provided at both ends of the thermal resistors, respectively, a memory that stores an estimation model of the core temperature of the living body that takes into consideration a non-thermal equilibrium state of the living body, and thermal resistance values of the thermal resistors, and an arithmetic circuit that estimates, based on the plurality of temperatures measured by the temperature sensors and the temperature sensors, the core temperature of the living body using the estimation model and the thermal resistance values, and the thermal resistance values are different from one another.

Described herein are embodiments of systems and methods that utilize images of a user's face to detect fever and intoxication. One embodiment of a system to detect fever 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 did not have a fever, 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 has a fever based on a deviation of the current pattern from the baseline pattern.

Described herein are embodiments of systems and methods for calculating glucose in a non-invasive manner using head-mounted sensors. In one embodiment, a system that calculates blood glucose levels includes a head-mounted contact photoplethysmography device that measures a signal indicative of a photoplethysmogram signal (PPG signal) at a first region comprising skin on a user's head, and a head-mounted camera configured to capture images of a second region comprising skin on the user's head. The system also includes a computer that identifies, based on the PPG signal, times of systolic notches and times of systolic peaks, and calculates the blood glucose level based on differences between a first subset of the images taken during the times of systolic notches and a second subset of the images taken during the times of systolic peaks. Optionally, the photoplethysmography device and the camera are couple to smartglasses worn on the user's head.

Embodiments disclosed herein involve a wearable-based system that can help determine in a privacy-preserving mariner 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.

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.

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.