Embodiments of the disclosure are drawn to apparatuses and methods for anomalous gas concentration detection. A spectroscopic system, such as a wavelength modulated spectroscopy (WMS) system may measure gas concentrations in a target area. However, noise, such as speckle noise, may interfere with measuring relatively low concentrations of gas, and may lead to false positives. A noise model, which includes a contribution from a speckle noise model, may be used to process data from the spectroscopic system. An adaptive threshold may be applied based on an expected amount of noise. A speckle filter may remove measurements which are outliers based on a measurement of their noise. Plume detection may be used to determine a presence of gas plumes. Each of these processing steps may be associated with a confidence, which may be used to determine an overall confidence in the processed measurements/gas plumes.

A measuring apparatus for measuring a spectrum of a gaseous sample includes a tunable laser light source to provide an illuminating light beam, a sample cell with an inner surface to provide scrambled light that is transmitted through the gaseous sample, a detector to detect intensity of transmitted scrambled light and a pressure control system to maintain an absolute pressure of the gaseous sample smaller than 50 kPa inside the sample cell to reduce spectral widths of spectral features of the gaseous sample. The measuring apparatus measures spectral transmittance values of the sample by modulating the spectral position of the illuminating light, and detecting the intensity of the transmitted light at different spectral positions. The divergence of the illuminating light beam in a transverse direction is greater than 20° to cause multiple consecutive reflections of the scrambled light from the inner surface.

A method for generating a illumination dual-comb signal that provides a low frequency train of interferograms (180) readable by a regular video-rate camera (160) comprising N pixels and a sampling frequency of V Hz to extract hyperspectral information (170), the method comprising providing a monochromatic signal, splitting the monochromatic signal in two split monochromatic signals, frequency shifting each monochromatic signal with an offset frequency below

[00001]$\frac{V}{2}\mathrm{Hz},$

generating two frequency combs having a difference in repetition below

[00002]$\frac{V}{2}\mathrm{Hz}$

by a nonlinear modulation of the two split monochromatic signals, generate the illumination dual-comb signal, Illuminating a target and employing a video-rate camera (160) to read a low frequency train of interferograms (180) based on a reflected and/or transmitted signal of the illumination dual-comb signal and performing Fourier transformation of the low frequency train of interferograms (180) detected by each pixel from the N pixels to extract the hyperspectral information (170).

This relates to systems and methods for measuring a concentration and type of substance in a sample at a sampling interface. The systems can include a light source, optics, one or more modulators, a reference, a detector, and a controller. The systems and methods disclosed can be capable of accounting for drift originating from the light source, one or more optics, and the detector by sharing one or more components between different measurement light paths. Additionally, the systems can be capable of differentiating between different types of drift and eliminating erroneous measurements due to stray light with the placement of one or more modulators between the light source and the sample or reference. Furthermore, the systems can be capable of detecting the substance along various locations and depths within the sample by mapping a detector pixel and a microoptics to the location and depth in the sample.

This relates to systems and methods for measuring a concentration and type of substance in a sample at a sampling interface. The systems can include a light source, optics, one or more modulators, a reference, a detector, and a controller. The systems and methods disclosed can be capable of accounting for drift originating from the light source, one or more optics, and the detector by sharing one or more components between different measurement light paths. Additionally, the systems can be capable of differentiating between different types of drift and eliminating erroneous measurements due to stray light with the placement of one or more modulators between the light source and the sample or reference. Furthermore, the systems can be capable of detecting the substance along various locations and depths within the sample by mapping a detector pixel and a microoptics to the location and depth in the sample.

A method for obtaining chemical and/or material specific information of a sample based on scattered light. The method comprises receiving detection data comprising at least two images. Each image is indicative of the intensity of scattered light i) for incident light of a different wavelength, or ii) for incident light of a different polarization state, or iii) of a different polarization state. The scattered light comprises an elastic scattering component that is due to Rayleigh scattering of the incident light in at least a portion of the sample. Alternatively, each image is indicative of the intensity of scattered light i) of a different wavelength, or ii) for incident light of a different polarization state, or iii) of a different polarization state, wherein the scattered light comprises an inelastic scattering component that is due to Raman scattering of the incident light in at least a portion of the sample. The method further comprises determining the chemical and/or material specific information of the sample based on the change in intensity of the elastic scattering component in dependence on the change in wavelength and/or the change in polarization state of the incident and/or scattered light.

A method for obtaining chemical and/or material specific information of a sample based on scattered light. The method comprises receiving detection data comprising at least two images. Each image is indicative of the intensity of scattered light i) for incident light of a different wavelength, or ii) for incident light of a different polarization state, or iii) of a different polarization state. The scattered light comprises an elastic scattering component that is due to Rayleigh scattering of the incident light in at least a portion of the sample. Alternatively, each image is indicative of the intensity of scattered light i) of a different wavelength, or ii) for incident light of a different polarization state, or iii) of a different polarization state, wherein the scattered light comprises an inelastic scattering component that is due to Raman scattering of the incident light in at least a portion of the sample. The method further comprises determining the chemical and/or material specific information of the sample based on the change in intensity of the elastic scattering component in dependence on the change in wavelength and/or the change in polarization state of the incident and/or scattered light.

An endoscopic imaging system for use in a light deficient environment includes an imaging device having a tube, one or more image sensors, and a lens assembly including at least one optical elements that corresponds to the one or more image sensors. The endoscopic system includes a display for a user to visualize a scene and an image signal processing controller. The endoscopic system includes a light engine having an illumination source generating one or more pulses of electromagnetic radiation and a lumen transmitting one or more pulses of electromagnetic radiation to a distal tip of an endoscope.

A stackable molecular spectroscopy cell includes a hollow body, a first cap affixed to a first surface of the hollow body, covering a first opening in the hollow body, and a second cap affixed to a second surface of the hollow body, covering a second opening in the hollow body, and forming a sealed cavity within the hollow body. The sealed cavity contains a dipolar gas having a pressure of less than 0.5 mbar. The stackable molecular spectroscopy cell also includes a metal layer covering an inner surface of the hollow body and an inner surface of the first and second caps, including a first aperture in the metal layer covering the inner surface of the first cap and a second aperture in the metal layer covering the inner surface of the second cap.

A stackable molecular spectroscopy cell includes a hollow body, a first cap affixed to a first surface of the hollow body, covering a first opening in the hollow body, and a second cap affixed to a second surface of the hollow body, covering a second opening in the hollow body, and forming a sealed cavity within the hollow body. The sealed cavity contains a dipolar gas having a pressure of less than 0.5 mbar. The stackable molecular spectroscopy cell also includes a metal layer covering an inner surface of the hollow body and an inner surface of the first and second caps, including a first aperture in the metal layer covering the inner surface of the first cap and a second aperture in the metal layer covering the inner surface of the second cap.