Mid-infrared spectroscopic analysis of tissue specimens can include training a learning model and using the trained learning model to classify tissue into at least two (or more than two) categories such as a tumor category, a non-tumor category, and a histology category. Resulting richer diagnostic indication can be provided and can optionally be mapped to a schema for RGB or other display. Efficient and accurate classification can employ an efficient linear SVM model representation. The model representation can include a β spectrum including the fuller wavelength set, a central tendency indicator (μ) of the training set, a spread indicator (σ) of the training set, and a scaling factor. Various types of illuminators and response detectors can include one or more Quantum Cascade Lasers, broadband light source configured to permit spectral separation, a thermal or other imaging array, among others.

Method and gas analyzer for measuring the concentration of a gas component in a measurement gas, a wavelength-tunable laser diode is actuated with a current, one part of the light generated by the laser diode is guided through the measurement gas to a measuring detector to generate a measuring signal, the other part of the light is guided to a monitor detector to generate a monitor signal, the current is varied in periodically consecutive scanning intervals to scan an absorption line of interest of the gas component as a function of the wavelength, the current is further modulated with a radio-frequency noise signal having a lower cut-off frequency selected as a function of the properties of the laser diode and high enough to ensure no wavelength modulation occurs and the measuring signal is correlated with the monitor signal and then evaluated to generate a measurement result.

A method of measuring a concentration of NO.sub.2 in a gaseous mixture using a multimode laser beam that covers a tunable spectral range with a width of no more than 5 nm, wherein the multimode laser beam provides a high resolution transmittance spectrum at an absorption cross section of NO.sub.2 molecules, and a system for measuring the concentration of NO.sub.2 in the gaseous mixture. Various combinations of embodiments of the system and the method are provided.

A combustion-zone chemical sensing system (100) is disclosed that includes pitch reflective optics (110) that collimate MIR electromagnetic energy from an input fiber (150), a reflector (120), catch reflective optics (112) that focus reflected MIR electromagnetic energy into an output fiber (152), and a detector (140) to detect MIR electromagnetic energy from the output fiber. An optical head (102) for sensing a combustion zone (104) is disclosed that includes pitch reflective optics (110) that collimate MIR electromagnetic energy from an input fiber (150) towards a reflector (120), catch reflective optics (112) that focus MIR electromagnetic energy, reflected from the reflector, into an output fiber (152), and an alignment housing that interfaces with structure adjacent the combustion zone. A method for determining gas concentration within a combustion zone is disclosed that includes collimating MIR electromagnetic energy exiting from an input fiber to traverse a combustion zone and focusing reflected MIR electromagnetic energy from the combustion zone into an output fiber.

A laser gas analyzer includes: a laser diode that irradiates a measurement target gas with laser light; a photodiode that receives the laser light that has passed through the measurement target gas; a processor that calculates a concentration of a component contained in the measurement target gas based on an amount of light of the laser light received by the photodiode; and a light emitting diode (LED) that irradiates LED light such that the LED light is received by the photodiode without passing through the measurement target gas.

A gas analyzer that easily facilitates alignment is provided. The gas analyzer is a gas analyzer for measuring a predetermined component in a measurement gas by irradiating light on the measurement gas from a light emitting element and receiving light that passes through the measurement gas. The gas analyzer includes a base member configured to be adjustable in position along at least one axis that is not parallel to the optical axis of the light emitting element, and a holding member configured to hold the light emitting element and to be held to the base member in an angularly adjustable manner around at least one axis that is not parallel to the optical axis.

A laser gas analyzer includes a light emitting unit including a laser element configured to emit laser light having a target wavelength band including a wavelength of an absorption line spectrum of the target gas, and a modulated light generation unit configured to supply a drive current to the laser element so that the laser element sweeps and modulates the laser light to have the target wavelength band, and a light receiving unit including a light receiving element configured to receive the laser light passing through the target space and output a detection signal, and a light reception signal processing unit configured to analyze the target gas according to the detection signal from the light receiving element. The light emitting unit and the light receiving unit communicate with each other using the laser light.

The present disclosure relates to a computer-implemented method for forecasting calibration spectra including a step of providing a machine learning model trained using historical calibration data corresponding to different gas species at different pressures. The computer-implemented method also includes steps of performing a calibration scan of one gas species at one pressure using an analyzer and generating calibration curves for the analyzer corresponding to one or multiple gas species at multiple pressures using the machine learning model and the calibration scan. Thereafter, a spectrum is obtained using the analyzer, and a concentration measurement is generated using the spectrum and at least one of the calibration curves.

Increased precision for liquid absorption spectroscopy, especially for in vivo samples of human analytes, is obtained by varying the signal or signal and interference central wavelengths when the temperature of the sample site varies beyond a selected threshold used for determining standardized signal or signal and interference central wavelengths. The amount of variance for a central wavelength of the signal beam which includes 1,150 nm is approximately 2 nm or less.

A measurement system comprising one or more semiconductor diodes configured to penetrate tissue comprising skin. The detection system comprising a camera, which may also include a direct or indirect time-of-flight sensor. The detection system synchronized to the pulsing of the semiconductor diodes, and the camera further coupled to a processor. The detection system non-invasively measuring blood within the skin, measuring hemoglobin absorption between 700 to 1300 nm, and the processor deriving physiological parameters and comparing properties between different spatial locations and variation over time. The semiconductor diodes may comprise vertical cavity surface emitting lasers, and the detection system may comprise single photon avalanche photodiodes. The measurement system may be used to observe eye parameters and differential blood flow. The system may be used with photo-bio-modulation therapy, or it may be used in advanced driver monitoring systems for multiple functions including head pose, eye tracking, facial authentication, and smart restraint control systems.