In one respect, disclosed is a soiling measurement device for measuring the loss of light transmission to photovoltaic (PV) devices in a photovoltaic array arising from the accumulation of soiling particles, comprising a light source, a reference photodetector, a soiling collection window, a photodetector positioned underneath the soiling collection window, and a measurement and control system.

A wearable computing device includes an electronic display with a configurable brightness level setting, a physiological metric sensor system including a light source configured to direct light into tissue of a user wearing the wearable computing device and a light detector configured to detect light from the light source that reflects back from the user. The device may further include control circuitry configured to activate the light source during a first period, generate a first light detector signal indicating a first amount of light detected by the light detector during the first period, deactivate the light source during a second period, generate a second light detector signal indicating a second amount of light detected by the light detector during the second period, generate a physiological metric based at least in part on the first light detector signal and the second light detector signal, and modify the configurable brightness level setting based on the second light detector signal.

An electronic device includes one or more light sources for emitting light toward a body part of a user and one or more optical sensors for capturing light samples while each light source is turned on and for capturing dark samples while the light source(s) are turned off. A signal produced by the one or more optical sensors is filtered and demodulated produce multiple demodulated signals each associated with a light source. Each signal associated with the light source(s) is analyzed to estimate or determine a physiological parameter of the user.

An electronic device includes one or more light sources for emitting light toward a body part of a user and one or more optical sensors for capturing light samples while each light source is turned on and for capturing dark samples while the light source(s) are turned off. A signal produced by the one or more optical sensors is filtered and demodulated produce multiple demodulated signals each associated with a light source. Each signal associated with the light source(s) is analyzed to estimate or determine a physiological parameter of the user.

In one aspect, a system for filtering signal interference from sensors signals includes a header comprising a frame and a powered component supported relative to the frame, and a sensor configured to detect electromagnetic waves indicative of a parameter associated with the header. In addition, the system includes an electronic control unit operably connected to the sensor such that the electronic control unit is configured to receive signals from the sensor associated with the detection of the electromagnetic waves. The electronic control unit is further configured to filter interference from the signals deriving from motion of the powered component relative to the sensor.

A system and method with AC coupling that reserves photodiode bandwidth in a biased configuration, allows optimal transimpedance amplifier performance, retains DC signal measurement capability, and does not introduce noise into the balanced detection signal.

A system and method with AC coupling that reserves photodiode bandwidth in a biased configuration, allows optimal transimpedance amplifier performance, retains DC signal measurement capability, and does not introduce noise into the balanced detection signal.

Disclosures of the present invention describe a method for calibrating laser power. During a laser power calibration of a laser optics product, reference intensity data and reference power data are adopted for generating a reference trend line with a R.sup.2 value that is equal to 1. As such, real intensity data that have a residual value smaller than a threshold value are adopted for generating a first trend line in combination with real power data. Moreover, the real intensity data that have a residual value greater than the threshold value are utilized for generating a second trend line in combination with corresponding real power data. Consequently, under an assistance of a predict trend line constituted by the first trend line and the second trend line, the laser power calibration is therefore completed after the laser optics product successively emits a laser beam by a few times.

Disclosures of the present invention describe a method for calibrating laser power. During a laser power calibration of a laser optics product, reference intensity data and reference power data are adopted for generating a reference trend line with a R.sup.2 value that is equal to 1. As such, real intensity data that have a residual value smaller than a threshold value are adopted for generating a first trend line in combination with real power data. Moreover, the real intensity data that have a residual value greater than the threshold value are utilized for generating a second trend line in combination with corresponding real power data. Consequently, under an assistance of a predict trend line constituted by the first trend line and the second trend line, the laser power calibration is therefore completed after the laser optics product successively emits a laser beam by a few times.

Methods and devices determine an eye strain indicator. In one aspect, an augmented reality (AR) device wearable by a user includes an image sensor and a processor coupled to the image sensor. The processor receives image data from the image sensor, determine that a display is within a field of view (FOV) of the AR device, determine an eye strain indicator based on the determination that the display is within the FOV of the AR device, and provide the eye strain indicator to the user.