A method for retrieving a corrected spectrum from a measured spectrum (e.g., retrieving a top-of-water spectrum from a measured top-of-atmosphere spectrum) includes creating a scene-specific model of a region of interest and performing a ray-tracing simulation to simulate rays of light that would reach an airborne (or spaceborne) sensor. The region of interest can be an optically complex area such as an inland or coastal body of water. Based on the ray-tracing simulation, a scene-specific correction for unwanted effects (e.g., adjacency effects, variable atmospheric conditions, and/or other suitable effects) is obtained. A corrected spectrum is obtained by correcting the measured spectrum using the scene-specific correction. The ray-tracing simulation may be performed using a graphical processing unit, allowing the scene-specific correction to be performed in real time or near real time.

Disclosed are hyperspectral/multiple spectral imaging methods and devices. A method obtains first and second spectral image datasets of a region of interest (ROI). The first spectral image dataset is characterized by a first spectral range and the second spectral image dataset is characterized by a second spectral range. The method then performs a first spectral analysis on the first spectral image dataset and a second spectral analysis on the second spectral image dataset. Afterwards, the method determines one or more spectral signature(s) at a deeper layer of the ROI.

A frequency-measurement method uses a dual frequency-comb spectrometer as an optical wavemeter to measure the frequency of a reference laser that is used to frequency-stabilize the spectrometer. The method includes measuring a walking rate of center bursts in a sequence of interferograms recorded by the spectrometer, determining a number of teeth in each of a plurality of Nyquist windows formed by the dual frequency-comb spectrometer, and determining a Nyquist number of the one Nyquist window covering the laser frequency. The reference laser frequency can then be determined from the number of teeth in each Nyquist window, the Nyquist number, and the comb spacing of either one of the two frequency combs of the dual frequency-comb spectrometer. The reference laser frequency does not need to be measured with a separate wavemeter, or calibrated with respect to a known atomic or molecular transition.

The present invention relates to a computer-implemented method for predicting a property value of interest in a sample investigated by infrared spectroscopy. The method aims at generating a calibration function. To this end, a set of calibration samples is selected, whereby outliers are identified and removed from the set of calibration samples. Outliers are determined using principal component analysis and singular value decomposition. The threshold value separating outliers from the remaining samples is calculated on the basis of a predetermined formulae. The threshold value may also be increased stepwise in order to dynamically set the threshold value, which is preferable for spectroscopic devices not operated under laboratory conditions.

A light wavelength measurement method of measuring a wavelength of target light includes: receiving target light on a second dispersion device that disperses the target light into a plurality of second beams which reach a plurality of positions corresponding to the wavelength of the target light (S106, S202); and measuring the wavelength of the target light, by using the plurality of the second beams as a vernier scale for measuring the wavelength of the target light within a wavelength range specified by a main scale (S108, S204).

Systems, devices, and methods of analyzing an interfered peak of a sample spectrum is disclosed. The sample spectrum may be generated using a detector of an optical spectrometer. The interfered peak may be produced by a plurality of spectral peaks of different wavelengths. The method may include generating interfered curve parameters representative of the peak shape of each spectral emission in the interfered peak based at least in part on a model of expected curve parameters for the optical spectrometer and a location of the interfered peak on the detector of the optical spectrometer; fitting a plurality of curves to the interfered peak, each curve corresponding to one of the plurality of spectral emissions of different wavelengths forming the interfered peak, wherein each curve is fitted using the interfered curve parameters provided by the model of expected peak parameters; and outputting the plurality of curves for further analysis.

The invention relates to a method for calibrating a spectroradiometer (1), comprising the following method steps: capture of light measurement data by the measurement of the radiation of at least one standard light source (4) using the spectroradiometer (1) that is to be calibrated; derivation of calibrated data from the light measurement data by the comparison of the captured light measurement data with known data of the standard light source (4); and calibration of the spectroradiometer (1) according to the calibration data. The aim of the invention is to provide a reliable and practical method for calibrating the spectroradiometer (1). In particular, the synchronism of spectroradiometers (1) situated in different locations (9, 10, 11) is to be produced simply and reliably. To achieve this aim, the validity, i.e. the usability, of the standard light source for the calibration is checked by a comparison of the light measurement data of the standard light source (4) with light measurement data of one or more additional standard light sources (4) of the same type, the validity of the standard light source (4) being established if the deviations of the light measurement data of the standard light sources (4) from one another lie below predefined limit values, and/or the standard light source (4) is measured using two or more standard spectroradiometers (1′) of the same type or of different types, the validity of the standard light source (4) being established if the deviations of the light measurement data from one another, said data being captured using the different standard spectroradiometers (1′), lie below predefined limit values.

Disclosed are an optical spectroscopy system using a pipeline-structured matched filter and a dual-slope analog digital converter, and a method for controlling the optical spectroscopy system. The optical spectroscopy system may comprise: a pipeline-structured matched filter sequentially connecting input voltage, transmitted by means of an amplifier, to a first capacitor and a second capacitor by means of a first switch terminal; and a dual-slope analog digital converter for sequentially receiving, by means of a second switch terminal, the electric charge stored in the first capacitor and second capacitor, and digitizing the input voltage.

A system comprising a light source, and a retention device configured to receive and retain a sample for measurement. The system includes a detector. An optical path couples light between the light source, the sample when present, and the detector. An optical objective is configured to couple light from the light source to the sample when present, and couple reflected light to the detector. A controller is configured to automatically control focus and/or beam path of the light directed by the optical objective to the sample when present. The detector is configured to output data representing a film thickness and a surface profile of the sample when present.

The present disclosure discloses a method for calibrating a spectrometer, comprising the steps of: transmitting light by means of a light source, wherein the light source has a known and substantially temporally steady emission spectrum; receiving the light as a receiving spectrum; comparing the receiving spectrum to the emission spectrum and determining a deviation; and taking into account the determined deviation during subsequent measurements using the spectrometer, if the deviation is greater than a tolerance value.