Systems and methods for path length selected diffuse correlation spectroscopy (PLS-DCS) are disclosed. The systems and methods are suitable for measuring dynamics of a target medium. The systems and methods can utilize light sources having a coherence length that is shorter than a path length distribution of the target medium and can utilize a reference optical path to interferometrically detect PLS-DCS signals. The coherence length and reference path length can be selected to provide sensitivity to portions of the target medium that correspond to a desired path length distribution.

This document describes techniques and devices for Fourier-transform infrared (FT-IR) spectroscopy using a mobile device. A mobile device (502) includes a light source (504) that emits light toward an interferometer (508) that uses mirrors to separate and recombine the light. The interferometer directs the recombined light toward a person. Light reflected from, or transmitted through, the person is received through a reception port (506) to a photodetector (510) that outputs photodetector data that corresponds to a measured light intensity of the reflected and transmitted light as a function of a path length of the light or a mirror position of the interferometer. Based on the photodetector data, an interferogram is generated. Applying a technique such as a Fourier transform to the interferogram, a spectrum data set of the reflected and transmitted light is generated. Based on the spectrum data set, a concentration of solutes in the person's blood is calculated.

An optical system for the detection of skin disease, such as melanoma, acquires images of a lesion on a subject's skin at different wavelengths and utilizes a sweeping arm rotating about the lesion in a clock-like sweep to produce diagnostically relevant metrics and classifiers from the image data so as to enhance detection of the skin disease.

Methods and systems are provided for lowering power consumption in an optical sensor, such as a pulse oximeter. In one example, a method for an optical sensor includes illuminating a light emitter of the optical sensor according to set sensor parameters, the sensor parameters set based on hardware noise or external interference characterization and light transmission or reflection of a tissue contributing to a signal output by the optical sensor, the sensor parameters including current drive parameters of the light emitter, and adjusting the current drive parameters of the light emitter to maintain a target signal to noise ratio of the signal output by the optical sensor.

Disclosed are absolute isolated light path structure, and a seat ring and a toilet seat using the absolute isolated light path structure. The absolute isolated light path structure comprises a light blocking plate, and a light emitting device and a light receiving device separated by the light blocking plate, the light blocking plate is configured for blocking light propagation between the light emitting device and the light receiving device, thereby avoiding the interference from the light emitted by the light emitting device to the light receiving device.

Optical imaging or spectroscopy described can use laminar optical tomography (LOT), diffuse correlation spectroscopy (DCS), or the like. An incident beam is scanned across a target. An orthogonal or oblique optical response can be obtained, such as concurrently at different distances from the incident beam. The optical response from multiple incident wavelengths can be concurrently obtained by dispersing the response wavelengths in a direction orthogonal to the response distances from the incident beam. Temporal correlation can be measured, from which flow and other parameters can be computed. An optical conduit can enable endoscopic or laparoscopic imaging or spectroscopy of internal target locations. An articulating arm can communicate the light for performing the LOT, DCS, or the like. The imaging can find use for skin cancer diagnosis, such as distinguishing lentigo maligna (LM) from lentigo maligna melanoma (LMM).

A device comprising a piece of planar substrate embedded with two sensors and two emitters. The substrate has a generally planar surface for application onto the wearer's body part. The emitters and sensors are shown to be arranged in such a way that no subset of any two emitters and one sensor, or subset of any two emitters and one sensor, forms a straight line, which prevents the two sensors from detecting the same noise caused by the same wearer movements.

An optical physiological sensor configured to perform high speed spectral sweep analysis of sample tissue being measured to non-invasively predict an analyte level of a patient. An emitter of the optical physiological sensor can be regulated to operate at different temperatures to emit radiation at different wavelengths. Variation in emitter drive current, duty cycle, and forward voltage can also be used to cause the emitter to emit a range of wavelengths. Informative spectral data can be obtained during the sweeping of specific wavelength regions of sample tissue.

A process quantifies a concentration of a targeted molecule in a liquid sample by pulsing signal and reference beams from their own sources, then spatially combining the pulsed beams into a single radiation beam which passes into the liquid sample and then detecting pulsed output beams after the single radiation beam passes out of the liquid sample. The pulsed outputs of the signal and reference beams are processed to obtain a value over a preselected period of time and, if an interference beam is used, it is processed with the reference beam to obtain a calibration curve adjustment representative of optical interference represented by at least one interfering molecule concentration which is used to calculate the concentration level of the targeted particle in the liquid sample. Two detectors, which may have an optical co-axial configuration, can be used for detection of pulsed beams.

An electronic device may include a housing and a PhotoPlethysmoGram (PPG) sensor disposed inside the housing. The PPG sensor may include a first Light Emitting Diode (LED) configured to generate light in a first wavelength band, a second LED configured to generate light in a second wavelength band, a third LED configured to generate light in a third wavelength band, a fourth LED configured to generate light in a fourth wavelength band, and a light receiving module including at least one photo diode. The electronic device may include a processor operatively coupled with the PPG sensor and a memory operatively coupled with the processor. The memory may include instructions that, when executed, cause the processor to measure optical densities of the light generated by the first LED to the fourth LED, and calculate a blood glucose value based at least in part on the measured optical densities.