Abstract: Present embodiments pertain to systems, apparatuses, and methods for analyzing and reporting the movements in mechanical structures, inanimate physical structures, machinery, and machine components, including automatically detecting aliased frequencies of a component on the structure which exhibits frequencies higher than the maximum frequency of the FFT spectrum calculated from the acquired data. To automatically detect the presence of aliased frequencies, a second virtually identical recording is acquired using a slightly different sampling rate and this provides the basis for detecting frequencies which are greater than the Nyquist sampling rate of the video recording and calculating the true frequency value of the aliased peaks in the frequency spectrum.

Abstract: A system for non-invasive hematological measurements includes a platform to receive a body portion of a user and an imaging device to acquire a set of images of a capillary bed in the body portion. For each image, a controller detects one or more capillaries in the body portion of the finger to identify a first set of capillaries by estimating one or more attributes of each capillary (e.g., structural attributes, flow attributes, imaging attributes, or combinations thereof), wherein at least one attribute of each capillary meets a predetermined criterion. The controller also identifies a second set of capillaries from the first set of capillaries such that each capillary of the second set of capillaries is visible in a predetermined number of images of the set of images.

Abstract: In some embodiments, systems, methods, and media for capsule-based multimode endoscopy are provided. In some embodiments, a probe for capsule-based multimode endoscopy is provided, the probe comprising: a rigid capsule; a flexible tether coupled to a proximal end of the capsule; a rotatable reflective surface disposed within the capsule; a static ball lens disposed within the capsule; a first optical fiber optically coupled to the ball lens, the first optical fiber passing through the flexible tether; a second optical fiber optically coupled to the ball lens, the second optical fiber passing through the flexible tether; a graded index fiber disposed between a distal end of the second optical fiber and the ball lens, the graded index fiber optically coupled to the second optical fiber and the ball lens.

Abstract: An apparatus for estimating bio-information, includes a pulse wave sensor configured to measure a pulse wave signal from a user, and a processor configured to obtain two or more parameters among a maximum point, an average point, and an onset point, from a waveform of the measured pulse wave signal, and combine the obtained two or more parameters to generate a pulse wave analysis result.

Abstract: An optical coherence imager for use in a clinical environment includes a laser source (24) for illuminating an area of tissue surface and a detector array (28) arranged to generate output signals indicative of detected light scattered from the tissue surface. An optical coherence image, such as a Flux image that is indicative of blood perfusion in the tissue, is generated from data collected at the detector. Detector output is analysed to identify a time series of such optical coherence images during which relative movement between tissue and detector is favourable. A representative optical coherence image is formed from an average of optical coherence images generated from data collected within the identified time series and extending over a period of multiple heartbeats. The representative optical coherence image thereby exhibits minimal movement noise and the effects of heartbeat are averaged out.

Abstract: Disclosed is a photoplethysmography (PPG) apparatus (100) for determining physiological changes, comprising: a light source to emit alight signal having a variable intensity dependent on a skin characteristic; first and second photodetectors (130) operable to detect a reflection of the light signal to provide a combined current signal; and a signal processing circuit operable to convert the current signal into a PPG signal for determining the physiological changes.

Abstract: One or more devices, systems, methods, and storage mediums for optical imaging medical devices, such as, but not limited to, Optical Coherence Tomography (OCT), single mode OCT, and/or multi-modal OCT apparatuses and systems, and methods and storage mediums for use with same, for triggering auto-pullback, including for devices or systems using blood clearing, are provided herein. Examples of applications include imaging, evaluating and diagnosing biological objects, such as, but not limited to, for Gastro-intestinal, cardio and/or ophthalmic applications, and being obtained via one or more optical instruments, such as, but not limited to, optical probes, catheters, capsules and needles (e.g., a biopsy needle). Techniques provided herein also improve processing and imaging efficiency while achieving images that are more precise.

Abstract: An optical apparatus for non-invasively measuring a bio-signal is provided. The optical apparatus may include an interface housing including: a guide part defined by an interior space of the interface housing and configured to guide an object to a measurement position; and a pressurizing part configured to induce congestion of a second portion of the object by pressing a first portion of the object when the object is disposed within the guide part; and a measurer including: a light source provided on an upper side of the interface housing and configured to emit light to the second portion of the object when the object is at the measurement position; and a detector configured to measure a bio-signal from the second portion by detecting light scattered or reflected from the second portion.

Abstract: Provided is an apparatus for non-invasively monitoring a health condition. The apparatus for monitoring health according to an example embodiment of the disclosure includes: a pulse wave sensor configured to obtain a first pulse wave signal in a first contact state of an object and a second pulse wave signal in a second contact state of the object; and a processor configured to estimate a degree of vasodilation based on an alternating current (AC) component of each of the first pulse wave signal and the second pulse wave signal, configured to monitor a vascular health condition based on the estimated degree of vasodilation, and configured to output a result of monitoring the vascular health condition.

Abstract: Disclosed are methods and devices useful for imaging blood-containing tissue, for example for angiography, especially retinal angiography, whereby an image is generated by dividing pixels of an image acquired at some wavelength range by corresponding pixels of an image acquired at a different wavelength range. In some embodiments, a first wavelength range includes predominantly light having wavelengths between about 400 nm and about 620 nm and a second wavelength range includes predominantly light having wavelengths between about 620 nm and about 800 nm.

Abstract: An apparatus for non-invasively measuring bio-information is provided. The apparatus for estimating bio-information may include a pulse wave sensor configured to measure a pulse wave signal from an object; a sensor position sensor configured to obtain sensor position information of the pulse wave sensor with respect to the object, based on the object being in contact with the pulse wave sensor; and a processor configured to estimate the bio-information based on blood vessel position information of the object, the sensor position information, and the pulse wave signal.

Abstract: A catheter device for crossing occlusions includes an elongate body, a central lumen extending within the elongate body from the proximal end to the distal end, a rotatable tip at the distal end of the elongate body, and an OCT imaging sensor. The rotatable tip is configured to rotate relative to the elongate body. The OCT imaging sensor includes an optical fiber coupled with the rotatable tip and configured to rotate therewith. A distal end of the elongate body includes one or more markers configured to occlude the OCT imaging sensor as it rotates. A fixed jog in the elongate body proximal to the distal end of the catheter positions the distal end of the catheter at an angle relative to the region of the catheter proximal to the fixed jog and is aligned with the one or more markers on the elongate body.

Abstract: Systems and methods for granting access to a user to a resource associated with a telecommunications network based on network-based authentication combined with biometric authentication, such as using a cardiac signature. Heartbeat information is received from a user via a mobile device. When a match is determined between the heartbeat information and a stored cardiac signature that uniquely identifies the user, then the user is authenticated to use the mobile device. A second authentication is performed using subscriber identity module (SIM) information associated with the mobile device. Based on the first and second authentication, the user is granted access to a resource associated with the telecommunications network, such as resources provided by a telecommunications service provider or a third party.

Abstract: A wearable device and a method for performing a registration process in the wearable device are provided. The wearable device includes a light source, a light sensor and a microcontroller that performs the method. In the method, the light source is activated to emit a detection light and the light sensor senses a reflected light. A light intensity of the reflected light is calculated. A registration value is produced based on the light intensity. Specifically, the detection light with a specific frequency to be registered in the registration value is used as a reference to detect whether the wearable device is properly worn by a person. For example, since the wearable device can be worn on the person's wrist, the registration value is used to detect whether the wearable device is away from the wrist.

Abstract: Provided herein are medical devices, systems and platforms to monitor tissue properties such as oxygen saturation, temperature and degree of tissue edema for diagnosis and post-operative patient monitoring. The medical devices may be handheld or portable or may be removable patches. The medical devices utilize light of various visible and near-infrared wavelengths to interrogate a tissue where the intensities of reflected light correlate to one or more tissue property. Also provided are methods for measuring tissue properties, for detecting pressure ulcers and for remotely monitoring in real time a surgical flap on a post-operative subject via the medical devices.

Abstract: Systems are provided for detecting the flow of blood in vasculature by illuminating the blood with a source of coherent illumination and detecting one or more time-varying properties of a light speckle pattern that results from the scattering of the coherent illumination by tissue and blood. The movement of blood cells and other light-scattering elements in the blood causes transient, short-duration changes in the speckle pattern. High-frequency sampling or other high-bandwidth processing of a detected intensity at one or more points in the speckle pattern could be used to determine the flow of blood in the vasculature. Such flow-measuring systems are also presented as wearable devices that can be operated to detect the flow in vasculature of a wearer. Systems and methods provided herein can additionally be applied to measure flow in other scattering fluid media, for example in a scattering industrial, medical, pharmaceutical, or environmental fluid.

Abstract: A method, a structure, and a computer system for a modular sensing unit. The structure comprises a sensor module, a power cable ribbon, and a component module, wherein the component module is in communication with and detachable from the sensor module via the power cable ribbon.

Abstract: An apparatus, method and computer program is described comprising: receiving video data for a scene; determining a movement measurement for at least some of a plurality of subframes of the video data; weighting the movement measurements to generate a plurality of weighted movement measurements, wherein the weighting is dependent on the subframe; and generating a movement indication for the scene from a combination of some or all of the weighted movement measurements.

Abstract: An electronic device can include a housing defining an aperture and at least partially defining an internal volume of the electronic device, an electromagnetic radiation emitter and an electromagnetic radiation detector disposed in the internal volume, and an optical component disposed in the aperture. The optical component can include a first and second transparent portions disposed above the electromagnetic radiation detector and the electromagnetic radiation emitter, and an opaque portion disposed between the first and second transparent portions. A conductive component can be in electrical communication with the opaque portion and one or more components of the electronic device.

Abstract: An electronic device can include a housing defining an aperture and at least partially defining an internal volume of the electronic device, an electromagnetic radiation emitter and an electromagnetic radiation detector disposed in the internal volume, and an optical component disposed in the aperture. The optical component can include a first and second transparent portions disposed above the electromagnetic radiation detector and the electromagnetic radiation emitter, and an opaque portion disposed between the first and second transparent portions and extending a thickness of the optical component. The first transparent portion, the second transparent portion, and the opaque portion can define a flush exterior surface of the electronic device.

Abstract: A method for determining one or more physiological parameters of a subject. The method includes providing a plurality of images of a vessel of the subject in response to illumination of the vessel to light of different wavelengths; converting each of the plurality of images of the vessel into at least two grayscale images, thereby generating a plurality of first grayscale images of a first wavelength range and a plurality of second grayscale images of a second wavelength range, the first wavelength range and the second wavelength range being different from each other; and determining the one or more physiological parameters of the subject based on at least the plurality of first grayscale images and the plurality of second grayscale images.

Abstract: The disclosure provides a heart rate monitor (HRM) circuit. The HRM circuit includes an analog front end (AFE). The AFE receives a Photoplethysmographic (PPG) signal, and generates a fine PPG signal. A motion cancellation circuit is coupled to the AFE, and receives the fine PPG signal and an accelerometer signal. The motion cancellation circuit subtracts the accelerometer signal from the fine PPG signal to generate a coarse heart rate. A peak detector is coupled to the motion cancellation circuit and the AFE, and generates an instantaneous heart rate. A filter is coupled to the peak detector, and generates an estimated heart rate from the instantaneous heart rate, the estimated heart rate is provided as a feedback to the peak detector.

Abstract: A physiological monitor gauge panel defines parameters to display on a physiological monitor via corresponding gauges. Gauge faces depict a range of parameter values for each of the parameters. An indicator designates a position on each gauge face corresponding to the current parameter value within the range of parameter values. The indicated position on each of the gauges is at the mid-point of each of the gauge faces when each of the parameters is at a nominal value.

Abstract: According to the present application, a computer-implemented method of predicting thyroid eye disease is disclosed. The method comprising: preparing a conjunctival hyperemia prediction model, a conjunctival edema prediction model, a lacrimal edema prediction model, an eyelid redness prediction model, and an eyelid edema prediction model, obtaining a facial image of an object, obtaining a first processed image and a second processed image from the facial image, wherein the first processed image is different from the second processed image, obtaining predicted values for each of a conjunctival hyperemia, a conjunctival edema and a lacrimal edema by applying the first processed image to the conjunctival hyperemia prediction model, the conjunctival edema prediction model, and the lacrimal edema prediction model, and obtaining predicted values for each of an eyelid redness and an eyelid edema by applying the second processed image to the eyelid redness prediction model and the eyelid edema prediction model.

Abstract: This invention generally relates to methods useful for measuring heart rate, respiration conditions, and oxygen saturation and a wearable device that incorporate those methods with a computerized system supporting data collection, analysis, readout and sharing. Particularly this present invention relates to a wearable device, such as a wristwatch or ring, for real time measuring heart rate, respiration conditions, and oxygen saturation.

Abstract: Systems and methods for assessing PPG signals generated based on transdermal optical data can include a computing device generating a color intensity signal using an acquired sequence of transdermal images of a subject. The computing device can compute a signal quality metric of the color intensity signal. The computing device can provide an indication of a quality of the color intensity signal for display on a display device associated with the computing device. The indication of the quality of the color intensity signal can be determined based on the signal quality metric.

Abstract: The invention relates to a device and a method for examining the retinal vascular endothelial function of the vessels of the retina at the fundus (F) of a patient's eye. Using a fundus camera, the vessels of the retina are stimulated with flicker light during a stimulation phase and sequences of images of areas of the fundus (F) are recorded, from which vascular parameters are derived which describe the retinal vascular endothelial function of the vessels. By imaging a macula stop (MB), which covers the macula, onto the fundus (F), the fundus (F) can be illuminated with a higher light intensity, which improves the stimulation effect and the image quality and/or reduces the strain on the patient.

Abstract: Controlled-environment facility resident behavioral and/or health monitoring may employ controlled-environment facility resident wearables each having a band configured to be affixed around a portion of a controlled-environment facility resident, irremovable by the resident and may include sensor(s) configured to measure biometric(s) of the controlled-environment facility resident and one or more physical parameter(s) experienced by the wearable, with a transmitter transmitting the biometric(s) and/or the physical parameter(s) to a controlled-environment facility management system.

Abstract: Aspects of the present disclosure provide methods, apparatuses, and systems for accurately determining sleep and wake onset based on a user's personalized physiological parameters for sleep and wake. First, a user is determined to be asleep using population level data. Thereafter, sensor collected data is used to determine the user's distribution of values of a physiological parameter when the user is asleep. This distribution of values is then used, instead of population-level data, to determine the user is asleep in real-time. As a result, the content and interventions are provided to help users get back to sleep. Further, the described techniques allow more accuracy in determining sleep statistics which can guide recommended interventions and therapies.

Abstract: There is provided a system for performing ambient light image correction. The system comprises a light source, a rolling shutter imaging unit configured to capture a plurality of images of the object at an exposure time shorter than the wave period of the pulsed illumination from the light source, and a control unit configured to generate a first composite image comprising a plurality of bright bands from the plurality of captured images by combining sections from the plurality of captured images which correspond to bright bands, generate a second composite image comprising a plurality of dark bands from the plurality of captured images by combining sections from the plurality of captured images which correspond to dark bands, and generate an ambient light corrected image based on a difference in pixel information between the first composite image and the second composite image.

Abstract: In accordance with one embodiment of the present disclosure, a method includes generating a plurality of icons, wherein each icon has a target frequency unique from each other, receiving brain activity data based on an epoch, generating a reference signal based on the epoch, calculating correlation coefficients between the brain activity data and the reference signal, wherein the correlation coefficients are calculated in a window that is within ±0.5 Hz of the target frequencies, including endpoints, determining a confidence score based on the correlation coefficients and the epoch, and determining a selected icon among the plurality of icons based on the correlation coefficients in response to the confidence score surpassing a threshold confidence score.

Abstract: Disclosed are a system and a method for determining a probability for a person to have arrhythmia. The system comprises means for measuring heartbeat interval of the person for a period of time; an accelerometer; means for measuring an electrocardiogram of the person; a user interface for providing information and alerts, and a processor. The processor is configured to detect a period of rest of the person, based on measurement data from the accelerometer; analyze the measured heartbeat interval to determine a probability of having arrhythmia for the person; generate an alert to the user interface, if the probability exceeds a predetermined threshold value, to alert the person to measure the electrocardiogram with the means for measuring an electrocardiogram; analyze the measured electrocardiogram to determine if the probable arrhythmia is confirmed; and indicate the confirmed arrhythmia to the person via the user interface.

Abstract: A disease prediction apparatus may include: a spectrometer configured to obtain an optical spectrum of a subject; and a processor configured to predict autofluorescence of the subject based on the optical spectrum by applying the optical spectrum to an autofluorescence prediction model, and predict a risk of developing a cardiovascular disease based on the predicted autofluorescence.

Abstract: Provided herein are methods and devices configured to detect the heart rate of a user. The method includes receiving at least one input signal, separating the input signal into signal components, receiving a motion signal from the user, and applying a Bayesian filter to the signal components and the motion signal to estimate the heart rate of the user. The method further includes calculating a combination of at least two reflected light signals from at least two different wavelengths. The device includes a photodetector configured to detect at least one reflected light signal resulting from the emitted at least two different wavelengths and a motion detector for detecting a motion signal. The device also includes a processing component configured to calculate a combination of the reflected light signals, separate the combination of detected light signals into signal components, and apply a Bayesian filter to the signals.

Abstract: Apparatus and methods provide wireless, disposable, continuous pulse oximeter sensor technology, useful and beneficial for a number of applications including relatively extended periods of data collection, and/or packaged in compact and easy-to-use assemblies. Economic fabrication and use provides flexible methodologies that can reduce the overall costs of monitoring and collecting patient's physiological data, and provide relatively greater ease and comfort to the patient. A disposable wireless continuous pulse oximeter sensor has a reduced emitter-detector separation, a low-power frontend, and a low-cost processor that sends waveforms to a host device so that the host can calculate and display the parameters of interest. Complications created by the reduced distance between emitter and detector are minimized by using an emitter-detector assembly with an optically dark background, and a bandage for improved optical compliance.

Abstract: Systems for obtaining an image of a target are provided including at least one multi-wavelength illumination module configured to illuminate a target using two or more different wavelengths, each penetrating the target at different depths; a multi-wavelength camera configured to detect the two or more different wavelengths illuminating the target on corresponding different channels and acquire corresponding images of the target based on the detected two or more different wavelengths illuminating the target; a control module configured synchronize illumination of the target by the at least one multi-wavelength illumination module and detection of the two or more different wavelengths by the camera; an analysis module configured to receive the acquired images of the target and analyze the acquired images to provide analysis results; and an image visualization module modify the acquired images based on the analysis results to provide a final improved image in real-time.

Abstract: It is known in the art to use an apparatus to enhance the visual appearance of the veins and arteries in a patient to facilitate insertion of needles into those veins and arteries. This application discloses a number of inventions that add additional data collection and presentation capabilities to a handheld vein enhancement apparatus and a set of processes for the collection of blood and the delivery of IV medicines that use the handheld device to mediate the process.

Abstract: Provided is a photoplethysmogram (PPG) sensing module including one or more light sources that emit light to a user; a plurality of optical sensors that receive reflected light from the user and generate sensing signals, each of the sensing signals being generated by one of the optical sensors; a read-out signal generating circuit that receives the sensing signals from the optical sensors and generate read-out signals by performing an analog-to-digital conversion on the sensing signals; and a signal processing circuit that receives the read-out signals, classifies the read-out signals according to one or more movement patterns of the user, measures a movement component of the user based on the classified read-out signals, and generates a PPG signal in which the movement component is removed.

Abstract: In one embodiment, a data processing method comprises obtaining one or more first photoplethysmography (PPG) signals based on one or more first light sources that are configured to emit light having a first light wavelength corresponding to a green light wavelength; obtaining one or more second PPG signals based on one or more second light sources that are configured to emit light having a second light wavelength corresponding to a red light wavelength, one or more of the first light sources and one or more of the second light sources being co-located; generating an estimated heart rate value based on one or more of the first PPG signals and the second PPG signals; and causing the estimated heart rate value to be displayed via a user interface on a client device.

Abstract: A method of displaying an area of interest within a surgical site includes modeling a patient's lungs and identifying a location of an area of interest within the model of the patient's lungs. The topography of the surface of the patient's lungs is determined using an endoscope having a first camera, a light source, and a structured light pattern source. Real-time images of the patient's lungs are displayed on a monitor and the real-time images are registered to the model of the patient's lungs using the determined topography of the patient's lungs. A marker indicative of the location of the area of interest is superimposed over the real-time images of the patient's lungs. If the marker falls outside of the field-of view of the endoscope, an arrow is superimposed over the real-time images to indicate the direction in which the marker is located relative to the field of view.

Abstract: Provided are a heart rate detection method and a wearable device. The wearable device includes a casing, a processor installed in the casing, and an optical heart rate sensing module and a distance sensing module connected to the processor and installed on a side of the casing facing a wearing part of a user. The method includes: detecting, by the distance sensing module, a positional relationship between the optical heart rate sensing module and the wearing part of the user to obtain relative position data of the optical heart rate sensing module relative to the wearing part of the user; and adjusting a signal transmission power of the optical heart rate sensing module according to the relative position data, and detecting, by the optical heart rate sensing module, a heart rate of the user.

Abstract: Systems and methods for blood pressure estimation using smart offset calibration can include a computing device associating a calibration photoplethysmographic (PPG) signal generated from a first sequence of image frames obtained from a photodetector of the computing device with one or more measurement values generated by a blood pressure measurement device different from the computing device. The computing device can obtain a recording PPG signal generated from a second sequence of image frames obtained from the photodetector, and identify a calibration model from a plurality of blood pressure calibration models based on the calibration PPG signal and the recording PPG signal. The computing device can generate a calibrated blood pressure value using the recording PPG signal, features associated with the calibration PPG signal and the identified calibration model.

Abstract: Disclosed herein are systems, methods, and devices for calibrating contrast measurements from laser speckle imaging systems to accurately determine unknown particle motion characteristics, such as flow rate. The calibration stores to memory calibration data, which may include a set of measurements from samples with known particle characteristics and/or estimates of noise, including the effects on contrast arising from undesired signals unrelated to the unknown particle motion characteristics. The calibration data may be accessed and used to correct an empirical measurement of contrast and/or interpolate a value of the unknown particle motion characteristic. The system may include a light source, photodetector, processor, and memory, which can be combined into a single device, such as a wearable device, for providing calibrated flow measurements. The device may be used, for example, to measure blood flow, cardiac output, and heart rate, and can be used to amplify the pulsatile signal.

Abstract: A device and method of using the device to detect the presence and composition of clots and other target objects in a circulatory vessel of a living subject is described. In particular, devices and methods of detecting the presence and composition of clots and other target objects in a circulatory vessel of a living subject using in vivo photoacoustic flow cytometry techniques is described.

Abstract: The present invention has an object to manage the manual ingestion (and failure of manual ingestion) of an ingestible object without making the user feel bothered. The present invention includes: a collating unit configured to collate the biological data acquired by a biosensor and the temporal changes of biological data that occur after a medicine is taken and after a medicine is not taken at a medicine-taking timing; and a warning output unit configured to output, on the basis of a result of the collation, information on whether or not a living body has taken the medicine.

Abstract: Controlled-environment facility resident behavioral and/or health monitoring may employ controlled-environment facility resident wearables each having a band configured to be affixed around a portion of a controlled-environment facility resident, irremovable by the resident and may include sensor(s) configured to measure biometric(s) of the controlled-environment facility resident and one or more physical parameter(s) experienced by the wearable, with a transmitter transmitting the biometric(s) and/or the physical parameter(s) to a controlled-environment facility management system.

Abstract: In some embodiments, systems, methods, and media for capsule-based multimode endoscopy are provided. In some embodiments, a probe for capsule-based multimode endoscopy is provided, the probe comprising: a rigid capsule; a flexible tether coupled to a proximal end of the capsule; a rotatable reflective surface disposed within the capsule; a static ball lens disposed within the capsule; a first optical fiber optically coupled to the ball lens, the first optical fiber passing through the flexible tether; a second optical fiber optically coupled to the ball lens, the second optical fiber passing through the flexible tether; a graded index fiber disposed between a distal end of the second optical fiber and the ball lens, the graded index fiber optically coupled to the second optical fiber and the ball lens.

Abstract: Present embodiments pertain to systems, apparatuses, and methods for analyzing and reporting the movements in mechanical structures, inanimate physical structures, machinery, and machine components, including automatically detecting aliased frequencies of a component on the structure which exhibits frequencies higher than the maximum frequency of the FFT spectrum calculated from the acquired data. To automatically detect the presence of aliased frequencies, a second virtually identical recording is acquired using a slightly different sampling rate and this provides the basis for detecting frequencies which are greater than the Nyquist sampling rate of the video recording and calculating the true frequency value of the aliased peaks in the frequency spectrum.

Abstract: A watch having a cover is described. An optical sensor subsystem is attached adjacent to or directly on an interior surface of the cover. In some cases, the optical sensor subsystem includes a substrate to which a light emitter and a light receiver are attached. The light receiver is configured to receive light emitted by the light emitter and reflected from the skin of a person that wears the watch. In some cases, the light emitter and light receiver are separated by a light-blocking wall that abuts the interior surface of the cover. In some cases, a light filter is attached adjacent or directly on the interior surface of the cover, between the cover and the light receiver.

Abstract: A technique for predicting fluid responsiveness in a critically ill patient comprises measuring physiological data of the patient, then generating an estimate of pulse pressure variability from a Fourier transform of the physiological waveform. Both invasive and non-invasive physiological data measurements may be used.