Abstract: An illustrative optical measurement system may include a module comprising a light source configured to emit light directed at a target, a plurality of detectors configured to detect target photon arrival times of target photons of the light after the light is scattered by the target, and a reference detector configured to detect reference photon arrival times of reference photons of the light after the light is reflected within the module. The system may further include a controller configured to determine, based on an output from the reference detector, an instrument response function (IRF) of the module.

Abstract: A wearable module for use in an optical measurement system includes a housing including a top surface, a light guide including a distal end portion adapted to protrude from the top surface of the housing, and a spring member configured to bias the distal end portion of the light guide away from the top surface of the housing. The light guide is configured to receive, at the distal end portion, photons from a light pulse scattered by a target within a body of a user and guide the received photons toward a photodetector.

Abstract: An illustrative optical measurement system includes a light source configured to emit light directed at a target, an array of photodetectors configured to detect photons of the light after the light is scattered by the target, and a processing unit configured to measure a noise level of a photodetector included in the array of photodetectors, the noise level comprising a dark count rate that measures a dark count divided by a time period, determine that the noise level meets a predetermined threshold comprising a dark count rate threshold, and prevent, based on the determining that the noise level meets the predetermined threshold, an output of the photodetector from being used in generating a histogram based on a temporal distribution of photons detected by the array of photodetectors, the preventing comprising switching the output to a monitoring circuit that monitors a characteristic of the optical measurement system separate from the photodetector.

Abstract: An illustrative multimodal measurement system includes a wearable assembly configured to be worn by a user; and a module configured to be removably inserted into the wearable assembly and comprising: a housing, a printed circuit board (PCB) and a light guide assembly configured to emit light directed at a target within the user. The light guide assembly comprises: a lower light guide portion housed within the housing and having a proximal end attached to the PCB, a conductive spring member housed within the housing and comprising a coil positioned around an external surface of the lower light guide portion, and a conductive upper light guide portion connected to the lower light guide portion and configured to protrude from an upper surface of the housing and be in contact with a surface of a body of the user.

Abstract: An illustrative optical measurement system includes a light source configured to emit light directed at a target, an array of photodetectors configured to detect photons of the light after the light is scattered by the target, and a processing unit. The processing unit is configured to measure a noise level of a photodetector included in the array of photodetectors and determine that the noise level meets a predetermined threshold. The processing unit is further configured to prevent, based on the determining that the noise level meets the predetermined threshold, an output of the photodetector from being used in generating a histogram based on a temporal distribution of photons detected by the array of photodetectors.

Abstract: An illustrative multimodal measurement system includes a wearable assembly configured to be worn by a user and comprising a plurality of light sources each configured to emit light directed at a target within the user, a plurality of detectors configured to detect arrival times for photons of the light after the light is scattered by the target, and a plurality of electrodes configured to be external to the user and detect electrical activity of the target.

Abstract: An optical measurement system includes a wearable device configured to be worn on a body of a user and a position alignment system. The wearable device includes a support assembly and a wearable assembly supported by the support assembly. The wearable assembly includes a plurality of light sources configured to emit a plurality of light pulses toward a target within the body of the user and a plurality of detectors each configured to receive a set of photons included in a light pulse included in the plurality of light pulses after the set of photons is scattered by the target. The position alignment system is configured to facilitate positioning of the wearable assembly at a same position on the body of the user during different use sessions of the wearable device.

Abstract: A wearable module assembly for an optical measurement system includes a first wearable module, a second wearable module, and a connector. The first and second wearable modules each include a light source configured to emit a light pulse toward a target within a body of a user, a housing that houses the light source and the plurality of detectors and includes a substantially hexagonal surface that faces a surface of the body of the user when the wearable module assembly is worn by the user, and a plurality of detectors each positioned at a fixed distance from the first light source and each configured to detect a set of photons included in the light pulse after the set of photons are scattered by the target. The connector directly connects the first wearable module and the second wearable module at mutually-facing side surfaces of the respective housings.

Abstract: An optical measurement system includes a wearable module having at least one time-resolved single photon photodetector configured to detect photons from at least one light pulse after the at least one light pulse is scattered by a target within a body of a user; at least one light guide configured to receive the photons and guide the photons to the at least one photodetector; and a housing that houses both the at least one photodetector and at least a portion of the at least one light guide. The optical measurement system further includes a signal processing circuit configured to determine a temporal distribution of the photons detected by the at least one photodetector and generate a histogram based on the temporal distribution of the photons.

Abstract: An optical measurement system includes a wearable device configured to be worn on a body of a user and a position alignment system. The wearable device includes a support assembly and a wearable assembly supported by the support assembly. The wearable assembly includes a plurality of light sources configured to emit a plurality of light pulses toward a target within the body of the user and a plurality of detectors each configured to receive a set of photons included in a light pulse included in the plurality of light pulses after the set of photons is scattered by the target. The position alignment system is configured to facilitate positioning of the wearable assembly at a same position on the body of the user during different use sessions of the wearable device.

Abstract: An optical measurement system includes a wearable device including a support assembly configured to be worn on a body of a user and a wearable assembly supported by the support assembly. The wearable assembly includes a plurality of light sources configured to emit a plurality of light pulses toward a target within the body of the user and a plurality of detectors each configured to receive a set of photons included in a light pulse included in the plurality of light pulses after the set of photons is scattered by the target. A position of the wearable assembly on the support assembly is adjustable.

Abstract: An illustrative calibration member made from a material that scatters light may be used to perform a calibration operation with respect to an optical measurement device having a plurality of light sources and a plurality of detectors distributed among a plurality of modules. The calibration member may form an exterior surface configured to support the optical measurement device and scatter photons of light emitted by the optical measurement device. The calibration operation may be performed based on arrival times of the scattered photons detected by the optical measurement device.

Abstract: An illustrative optical measurement device includes a light source configured to emit light pulses directed at a target. The optical measurement device further includes a detector configured to detect arrival times for photons of the light pulses after the photons are scattered by the target. The optical measurement device further includes a processing unit configured to generate, based on the arrival times of the photons at the detector, histogram data associated with the target. The processing unit is further configured to determine, based on the histogram data, an absolute optical property associated with the target. The processing unit is further configured to determine, based on the absolute optical property, a blood oxygenation level of the user, and perform an operation based on the blood oxygenation level.

Abstract: An illustrative optical measurement device includes a light source configured to emit light pulses directed at a target. The optical measurement device further includes a detector configured to detect arrival times for photons of the light pulses after the photons are scattered by the target. The optical measurement device further includes a processing unit configured to generate, based on the arrival times of the photons at the detector, histogram data associated with the target. The processing unit is further configured to determine, based on the histogram data, an absolute optical property associated with the target. The processing unit is further configured to determine, based on the absolute optical property, a blood oxygenation level of the user, and perform an operation based on the blood oxygenation level.

Abstract: A wearable module assembly for an optical measurement system includes a first wearable module, a second wearable module, and a connector. The first and second wearable modules each include a light source configured to emit a light pulse toward a target within a body of a user, a housing that houses the light source and the plurality of detectors and includes a substantially hexagonal surface that faces a surface of the body of the user when the wearable module assembly is worn by the user, and a plurality of detectors each positioned at a fixed distance from the first light source and each configured to detect a set of photons included in the light pulse after the set of photons are scattered by the target. The connector directly connects the first wearable module and the second wearable module at mutually-facing side surfaces of the respective housings.

Abstract: An illustrative optical measurement system includes a signal generator configured to generate a signal and a processing unit configured to direct the signal generator to apply the signal to a TDC included in the optical measurement system and generate, based on timestamp symbols recorded by the TDC in response to the signal, characterization data representative of a nonlinearity of the TDC.

Abstract: An illustrative optical measurement system includes a light source configured to emit light directed at a target, an array of photodetectors configured to detect photons of the light after the light is scattered by the target, and a processing unit. The processing unit is configured to measure a noise level of a photodetector included in the array of photodetectors and determine that the noise level meets a predetermined threshold. The processing unit is further configured to prevent, based on the determining that the noise level meets the predetermined threshold, an output of the photodetector from being used in generating a histogram based on a temporal distribution of photons detected by the array of photodetectors.

Abstract: An illustrative biopotential measurement system includes a plurality of electrodes each configured to record a different signal included in a plurality of signals representative of electrical activity of a target within a user; a plurality of non-inverting operational amplifier circuits each connected to a different electrode included in the plurality of electrodes and each configured to output a different amplified signal included in a plurality of amplified signals representative of amplified versions of the plurality of signals; and a common-mode feedback circuit configured to measure a common-mode signal between the plurality of amplified signals and provide the common-mode signal to the non-inverting operational amplifier circuits. The non-inverting operational amplifier circuits are configured to use the common-mode signal to generate voltage-divided feedback signals used to generate the plurality of amplified signals.

Abstract: An optical measurement system includes a wearable module having at least one time-resolved single photon photodetector configured to detect photons from at least one light pulse after the at least one light pulse is scattered by a target within a body of a user; at least one light guide configured to receive the photons and guide the photons to the at least one photodetector; and a housing that houses both the at least one photodetector and at least a portion of the at least one light guide. The optical measurement system further includes a signal processing circuit configured to determine a temporal distribution of the photons detected by the at least one photodetector and generate a histogram based on the temporal distribution of the photons.

Abstract: A wearable module for use in an optical measurement system includes a housing including a top surface, a light guide including a distal end portion adapted to protrude from the top surface of the housing, and a spring member configured to bias the distal end portion of the light guide away from the top surface of the housing. The light guide is configured to receive, at the distal end portion, photons from a light pulse scattered by a target within a body of a user and guide the received photons toward a photodetector.