A computer-implemented method includes controlling an instrument to measure a fluorescence emission spectrum of a sample including a first peak emission wavelength and at least a second peak emission wavelength, emitted in response to an excitation wavelength and controlling the instrument to measure an absorbance obtained at the excitation wavelength of the sample. The method may include determining, using the computer, a ratio of the measurements at either the second peak emission wavelength, or a sum of measurements at a plurality of peak emission wavelengths including at least the first peak emission wavelength and the second peak emission wavelength, to the first peak emission wavelength, and calculating, using the computer, a value for a quality parameter based on a combination of at least the ratio and the absorbance measurement. The method may include controlling an associated process based on the quality parameter.

A concentration measurement device for measuring the concentration of a measured fluid within a measurement cell by detecting transmitted light that has passed through the measurement cell having a light incidence window and a light emission window disposed opposing to each other, comprising a reflected-light detector for detecting reflected light of the light incidence window.

A temperature measurement system configured to measure a temperature of a target object having a first main surface and a second main surface includes a light source unit configured to emit output light penetrating the target object and including a first wavelength range and a second wavelength range; a measurement unit configured to measure a spectrum of reflected light; an optical path length ratio calculator configured to calculate an optical path length ratio between the output light of the first wavelength range and the output light of the second wavelength range; and a temperature calculator configured to calculate the temperature of the target object based on the optical path length ratio and a previously investigated relationship between the temperature of the target object and a refractive index ratio between the output light of the first wavelength range and the output light of the second wavelength range.

A method for quality testing asphalt includes: directing light from a light source to at least one surface of asphalt; detecting light reflected or refracted from the at least one surface of the asphalt using a light detector; and assigning a number indicating the quality of the asphalt in response to detecting light reflected or refracted from the at least one surface of the asphalt.

A measurement device for spectroscopic constituent analysis includes a control unit, a light source, a sample holder arranged in the beam path of the light source, and a spectral measurement module. The measurement module comprises at least one photosensor with organic photodiodes arranged on a substrate and a temperature sensor arranged at the photosensor. During a sample measurement, a method using the measurement device comprises: detecting an actual temperature at the photosensor; pivoting-in a dark reference sample and measuring a dark reference value; pivoting-in a bright reference sample and measuring a bright reference value; measuring a spectral value of the sample and correcting the spectral value by means of a correction calculation by way of the control unit using the dark reference value, the bright reference value, the spectral value of the sample, the temperature and using values which were determined in a pre-calibration and stored in the control unit.

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.

According to one aspect, the present description relates to a stabilized interferometric system comprising a light source (210) for emitting an initial beam (B.sub.0) of coherent light and 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 (B.sub.0m) resulting from a spatial modulation of a parameter of said first part of said initial beam based on said input data. The stabilized interferometric system further comprises a scattering medium (230) configured to receive said spatially modulated beam and a detection unit (240) configured to acquire an interference pattern (IN.sub.0) in a first detection plane (241) at an output of said scattering material, wherein said interference pattern results from the interferences between randomly scattered optical paths taken by the spatially modulated beam through the scattering material. The stabilized interferometric system further comprises 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.

Disclosed is an optical flow cell (300) comprising: a housing (910) forming; an enclosed and elongated fluid channel (920) arranged along a first axis (923); a first light guide (961) and a second light guide (962) generally concentrically arranged along a second axis (970) and on opposite side walls of the fluid channel, said first and second light guides having ends (961c,962c) removed in situ to provide a sensing gap (d).

A baler includes a near-infrared testing system configured to receive near-infrared radiation reflected by plant material in a bale and to analyze the near-infrared radiation and generate evaluation data reflecting one or more properties of the plant material. The near-infrared testing system is calibrated using a calibration sample at a calibration temperature. A temperature sensor measures a sample temperature of a crop sample of the plant material and a temperature alteration mechanism adjusts the sample temperature of the crop sample so that the sample temperature matches the calibration temperature of the calibration sample before the near-infrared testing system receives the near-infrared radiation reflected by the plant material. A computer receives and combine the evaluation data of the plant material to produce overall evaluation data reflecting one or more overall properties for the at least one bale of the plurality of bales, and assign the overall evaluation data to the bale.

An optical measurement method and system. The system includes, and method applies, a light source, a beamsplitter, at least one filter, a output photodetector for acquiring data of a sample, and a correction photodetector for correcting and maintaining output intensity from the light source. The filter is located between the light source and the correction photodetector for normalizing the spectrum of the input light being applied to input light correction. The filter may be incorporated into the beamsplitter and may be tuned to filter light from the light source for providing non-zero transmission of light with a near-zero gradient for wavelengths in a portion of the spectrum of the input light being applied to the sample and read by the output photodetector. The filter may also or alternatively be located downstream of the beamsplitter to correct for wavelength sensitivity of the correction photodetector.