An optical gas concentration measurement apparatus is disclosed. The optical gas concentration measurement apparatus includes a thermally insulated enclosure that has a gas sample cell situated within. A thermally-insulating, light-guiding element passes through an access port of the thermally insulated enclosure and is configured to direct light from a light source outside of the thermally insulated enclosure to the gas sample cell. A light detector outside of the thermally insulated enclosure is optically coupled to the gas sample cell and an electronic assembly outside of the thermally insulated enclosure is configured to receive information from the light detector.

A concentration measurement device 100 includes a light source 22 for generating incident light to a measurement space 10A, a photodetector 24 for receiving light emitted from the measurement space, and an arithmetic control circuit 26 for calculating a concentration of a measurement fluid on the basis of an output of the photodetector, and the light source includes a first light-emitting element 22a for generating light having a first wavelength, and a second light-emitting element 22b for generating light having a second wavelength, and the concentration measurement device is configured so as to calculate the concentration using either light of the first wavelength or the second wavelength on the basis of the pressure or temperature of the measurement fluid.

The concentration measurement device 100 includes an electric unit 20 having a light source 22 and a photodetector 24, a fluid unit 10 having a measurement cell 1, optical fibers 11 and 12 for connecting the electric unit 20 and the fluid unit 10 and is configured to measure the concentration of the fluid in the measurement cell by detecting the light incident from the light source 22 to the measurement cell and then emitted from the measurement cell by the photodetector 24, where optical connection parts 32 and 34 connected to the optical fibers 11, 12 and the light source 22 or the photodetector 24 are integrally provided in the electric unit 20.

The present description relates to a stabilized interferometric system comprising: a light source (210) for emitting an initial beam of coherent light; a spatial light modulator (220) configured to receive at least a first part of said initial beam and input data (203) and configured to emit a spatially modulated beam resulting from a spatial modulation of a parameter of said first part of said initial beam based on said input data; a scattering medium (230) configured to receive said spatially modulated beam; a detection unit (240) configured to acquire an interference pattern (IN.sub.0) resulting from the interferences between randomly scattered optical paths taken by the spatially modulated beam through the scattering material; a control unit (250) configured to vary the frequency of the laser source in order to at least partially compensate a change in said interference pattern resulting from a change in at least one environmental parameter.

A concentration measurement method is performed using a concentration measurement device comprising: a measurement cell for flowing a fluid to be measured; a light source for generating light incident on the measurement cell; a photodetector for detecting light emitted from the measurement cell; an arithmetic unit for calculating the absorbance and concentration of the fluid to be measured based on an output of the photodetector; and a temperature sensor for measuring the temperature of the fluid to be measured. The concentration measurement method includes: a step of flowing a gas whose molecular structure varies with the temperature as the fluid to be measured in the measurement cell; a step of making light of a wavelength absorbable by the fluid to be measured to be incident from the light source to the measurement cell; a step of measuring the intensity of light emitted from the measurement cell by the photodetector; and a step of calculating the concentration of the fluid to be measured based on the temperature and the output of the photodetector measured by the temperature sensor.

A Concentration measurement device 100 comprises: a measurement cell 4 having a flow path through which a gas flows, a light source 1 for generating incident light to the measurement cell, a photodetector 7 for detecting light emitted from the measurement cell, a pressure sensor 20 for detecting a pressure of the gas in the measurement cell, a temperature sensor 22 for detecting a temperature of the gas in the measurement cell, and an arithmetic circuit 8 for calculating a concentration of the gas based on an output P of the pressure sensor, an output T of the temperature sensor, an output I of the photodetector, and an extinction coefficient α, wherein the arithmetic circuit 8 is configured to calculate the concentration using the extinction coefficient α determined on the basis of the output of the temperature sensor 22.

A concentration measurement method is performed using a concentration measurement device comprising: a measurement cell for flowing a fluid to be measured; a light source for generating light incident on the measurement cell; a photodetector for detecting light emitted from the measurement cell; an arithmetic unit for calculating the absorbance and concentration of the fluid to be measured based on an output of the photodetector; and a temperature sensor for measuring the temperature of the fluid to be measured. The concentration measurement method includes: a step of flowing a gas whose molecular structure varies with the temperature as the fluid to be measured in the measurement cell; a step of making light of a wavelength absorbable by the fluid to be measured to be incident from the light source to the measurement cell; a step of measuring the intensity of light emitted from the measurement cell by the photodetector; and a step of calculating the concentration of the fluid to be measured based on the temperature and the output of the photodetector measured by the temperature sensor.

The concentration measurement device 100 includes an electric unit 20 having a light source 22 and a photodetector 24, a fluid unit 10 having a measurement cell 1, a first light-transmission member 11 for transmitting light from the light source to the measurement cell, a second light transmission member 12 for transmitting light from the measurement cell to the photodetector, a lens 3A provided in the fluid unit, the lens 3A being arranged such that light from the first light transmission member is to be incident on the first position and light is to be emitted from the second position to the second light transmission member, a pressure sensor 5 for measuring pressure of fluid flowing through the measurement cell, and an arithmetic circuit 28 for detecting concentration of the fluid flowing through the measurement cell, the arithmetic circuit being configured to calculate the fluid concentration based on the output of the photodetector and a correction factor related to the pressure output by the pressure sensor and the concentration of fluid in order to reduce the measurement error due to the refractive index of the fluid.

A Concentration measurement device 100 comprises: a measurement cell 4 having a flow path through which a gas flows, a light source 1 for generating incident light to the measurement cell, a photodetector 7 for detecting light emitted from the measurement cell, a pressure sensor 20 for detecting a pressure of the gas in the measurement cell, a temperature sensor 22 for detecting a temperature of the gas in the measurement cell, and an arithmetic circuit 8 for calculating a concentration of the gas based on an output P of the pressure sensor, an output T of the temperature sensor, an output I of the photodetector, and an extinction coefficient α, wherein the arithmetic circuit 8 is configured to calculate the concentration using the extinction coefficient α determined on the basis of the output of the temperature sensor 22.

A material evaluating device for an agricultural work machine comprising: a light source for illuminating one or more constituent materials to be examined; a spectrometer for providing a spectral signal related to the wavelength-specific intensity of light reflected by the constituent materials; and an evaluation device configured to determine the content of one or more constituent materials using the spectral signal of the spectrometer and a calibration data, wherein a property signal relating to a property of the one or more constituent materials is supplied to the evaluation device and the evaluation device is configured, using the property signal, to determine the content of the one or more constituent materials.