A gas analyzer includes a reference gas chamber and a measurement gas chamber in a single cavity, and a micro-flow infrared gas detection device. A water adjustment device is disposed in the micro-flow infrared gas detection device. By identifying the overlapping phenomenon of the absorption spectrums of the gaseous water and the gas to be measured and by taking advantage of the difference between the infrared absorption spectrums of the gaseous water and the gas to be measured, the water adjustment valve is adjusted to change the velocity variation due to the expansion of the gas in front and rear gas chambers and the water adjustment buffer gas chamber of the micro-flow infrared gas detection device, such that the detected infrared spectrum is located within the absorption spectrum of the gas to be measured while away from the absorption spectrum of the gaseous water, thus addressing the water interference issue.

An electrically modulated light source is provided. The electrically modulated light source comprises a carbon nanotube film structure. The electrically modulated light source heats up to a highest temperature and emits thermal radiation in less than 10 milliseconds after a voltage is applied, and the electrically modulated light source cools down to an initial temperature of the electrically modulated light source in less than 10 milliseconds after the voltage is removed. An modulation frequency of the electrically modulated light source is greater than or equal to 150 KHz. A non-dispersive infrared spectrum detection system used the electrically modulated light source, and a method for detecting gas used the electrically modulated light source are also provided.

An open path gas detector for detecting the presence of a target gas in the presence of fog or water vapor. A transmitter transmits flashes of optical energy along a path in an area under surveillance, including energy at a sample wavelength region at which the target gas is absorbed, at a reference wavelength region not significantly absorbed by the target gas, and at a synchronization wavelength region different from the first and second wavelengths. A receiver includes a sample channel responsive to the optical energy at the sample wavelength region, a reference channel responsive to optical energy at the reference wavelength region, and a third synchronization channel responsive to the optical energy at the synchronization wavelength region. The receiver detects the target gas and synchronizes operation of the receiver to the transmitter flashes of optical energy using the output of the synchronization channel.

A spectral imaging system configured to obtain spectral measurements in a plurality of spectral regions is described herein. The spectral imaging system comprises at least one optical detecting unit having a spectral response corresponding to a plurality of absorption peaks of a target chemical species. In an embodiment, the optical detecting unit may comprise an optical detector array, and one or more optical filters configured to selectively pass light in a spectral range, wherein a convolution of the responsivity of the optical detector array and the transmission spectrum of the one or more optical filters has a first peak in mid-wave infrared spectral region between 3-4 microns corresponding to a first absorption peak of methane and a second peak in a long-wave infrared spectral region between 6-8 microns corresponding to a second absorption peak of methane.

Provided is a gas detection apparatus which suppresses occurrences of distortions of the optical path to reduce fluctuations of the gas detection sensitivity. A gas detection apparatus 1 includes a substrate 2; a light emitting element 3 disposed in a first region 21 in a main surface 20 of the substrate 2 for emitting light; a light receiving element 4 disposed in a second region 22 in the main surface 20 of the substrate 2 for receiving the light; a light guide member 5 for guiding the light emitted by the light emitting element 3 to the light receiving element 4; and a joint member 6 joining the substrate 2 and the light guide member 5. The joint member 6 serves as a rotation axis when the light guide member 5 is displaced relative to the substrate 2.

A method includes decomposing a training set to obtain a principal component matrix having a plurality of principal component vectors. The method also includes variably rejecting portions of a sample spectrum vector that do not correspond to a selected one of the plurality of principal component vectors by incrementally providing a coefficient indicative of the weighting of the selected principal component vector for selected sub-regions. A corrected spectrum vector can be obtained by excluding certain sub-regions of the sample spectrum vector and corresponding principal component vector, multiplying the sample spectrum vector with the principal component matrix for non-excluded sub-regions, providing a predicted interference vector, and subtracting the predicted interference vector from the sample spectrum vector.

A spectral imaging system configured to obtain spectral measurements in a plurality of spectral regions is described herein. The spectral imaging system comprises at least one optical detecting unit having a spectral response corresponding to a plurality of absorption peaks of a target chemical species. In an embodiment, the optical detecting unit may comprise an optical detector array, and one or more optical filters configured to selectively pass light in a spectral range, wherein a convolution of the responsivity of the optical detector array and the transmission spectrum of the one or more optical filters has a first peak in mid-wave infrared spectral region between 3-4 microns corresponding to a first absorption peak of methane and a second peak in a long-wave infrared spectral region between 6-8 microns corresponding to a second absorption peak of methane.

An absorption spectroscopic system is provided with a detector that detects an intensity of light transmitted through a gas, a total pressure sensor that measures a total pressure of the gas, an interference gas partial pressure-absorbance relationship storage unit that stores interference gas partial pressure-absorbance relationship data, an interference gas partial pressure estimation unit that estimates the partial pressure of the interference gas based on the total pressure measured by the total pressure sensor, an interference gas absorbance conversion unit that converts an estimated partial pressure of the interference gas estimated by the interference gas partial pressure estimation unit into an absorbance of the interference gas based on the interference gas partial pressure-absorbance relationship data, and a target gas absorbance calculation unit that calculates an absorbance of the target gas based on output values from the detector and on the absorbance of the interference gas.

A gas analyzer includes a reference gas chamber and a measurement gas chamber in a single cavity, and a micro-flow infrared gas detection device. A water adjustment device is disposed in the micro-flow infrared gas detection device. By identifying the overlapping phenomenon of the absorption spectrums of the gaseous water and the gas to be measured and by taking advantage of the difference between the infrared absorption spectrums of the gaseous water and the gas to be measured, the water adjustment valve is adjusted to change the velocity variation due to the expansion of the gas in front and rear gas chambers and the water adjustment buffer gas chamber of the micro-flow infrared gas detection device, such that the detected infrared spectrum is located within the absorption spectrum of the gas to be measured while away from the absorption spectrum of the gaseous water thus addressing the water interference issue.

A gas concentration-length quantification method may include: acquiring a multi-spectral image of detected radiance including a plurality of pixels using a multi-spectral optical gas imaging camera; estimating a background radiance for at least one of the pixels; calculating a gas concentration-length for the at least one of the pixels based on the detected radiance and the estimated background radiance; and triggering an alert when each alert condition in a list of alert conditions is satisfied. A multi-spectral configuration of the camera may include a reference band that is outside an absorption window of a target gas and an active band that includes at least a portion of the absorption window. Estimating the background radiance may include determining a model relating a detected radiance of the active band to a detected radiance of the reference band and using the model to estimate the background radiance for the active band.