A gas analysis system with an FTIR spectrometer preferably utilizes a long path gas cell, a narrow band detector, and an optical filter that narrows the detection region. The interferograms are further prevent baseline drift and analyze the resultant spectra.

A method and an apparatus are presented for monitoring a concentration of a specific halogen in a body of water such as a spa or bathing unit for example. The apparatus comprises a housing in which is positioned an optical absorption analyzer for making first and second measurement of transmission of ultraviolet light from a light source emitting light at a specific wavelength. The second and first measurements are taken respectively before and after the ultraviolet light has travelled through a sample of water and are used to derive a concentration of the specific halogen. The derived concentration may then be communicated to a user using a display device and/or may be used to control operational components of a bathing unit for adjusting the concentration of halogen in the water. In some practical implementations, the apparatus may be embodied as a standalone device, which may be configured to float on the water of the bathing unit or, alternatively, may be configured for being installed in-line in a water circulation path of the bathing input by connecting the housing to circulation piping.

Systems and methods are disclosed to determine the concentration of a species within a sample. An example method may include collecting optical loss data over a range of frequencies from the sample using a spectroscopy system; placing the optical loss data into a plurality of bins, each bin having a defined frequency width; determining an average optical loss data value for the optical loss values within each bin that have an optical loss value less than a threshold value; removing the optical loss data within each bin having a value outside a tolerance range bounding the average optical loss data value for the respective bin; fitting a spectral curve to the remaining optical loss data; and determining the concentration of the species within the sample based on the spectral curve.

An information processing method includes the steps of calculating information on object illumination light for illuminating an object based on spatial distribution information of illumination light and orientation information of the object, and correcting information on the reflected light so as to reduce influence of the object illumination light based on the information on the object illumination light and information on the reflected light from the object.

Provided is a terahertz wave spectrometry system that is capable of easily identifying and quantitating an analyzing target molecule in an analyte, even if the analyte contains water, by calculating a baseline function expressing the absorption characteristic of water peculiar to the terahertz wave.

A measuring device (1) includes a first signal generation section (3) and a first removal section (5). The first signal generation section (3) generates a first source signal (x1(t)) including a fundamental and a plurality of harmonics based on a first physical quantity (p1) and a second physical quantity (p2). The first removal section (5) removes some or all of the harmonics from the first source signal (x1(t)). The first source signal (x1(t)) is a periodic signal, and one period of the first source signal (x1(t)) includes a first signal (p1), a second signal (p2), and a reference signal (pr). The first signal (p1) has a first duration (w1) and indicates the first physical quantity (p1). The second signal (p2) has a second duration (w2) and indicates the second physical quantity (p2). The reference signal (pr) has a third duration (w3) and indicates the reference physical quantity (pr).

A concentration of a chosen molecule in a liquid phase in a sample space is determined through use of a signal channel output/reference channel ratio obtained by use of an NDIR absorption technique in which scattering noise attributable to the liquid phase is reduced by alternately and successively pulsing infrared radiation from signal and reference sources which are multiplexed and collimated into a pulsed beam directed through the sample space containing the liquid phase and the pulse frequency is sufficiently fast so that a given molecule of the chosen molecule will not pass in and out of the sample space within the pulse frequency.

A method for measuring the concentration of a gas component in a measurement gas using a gas analyzer comprises varying the wavelength of the light of a wavelength-tunable light source within periodically consecutive scan intervals for wavelength-dependent scanning of a gas component absorption line of interest. The method also comprises modulating the wavelength of the light of the wavelength-tunable light source with a frequency, guiding the modulated light through the measurement gas onto a detector and demodulating a measurement signal generated by the detector in the event of a harmonic of the frequency. The method further comprises producing a measurement result by fitting a desired curve to the profile of the demodulated measurement signal. A function orthogonal to the desired curve is provided, and an orthogonal component of the measurement result is produced by fitting the orthogonal function to the profile of the demodulated measurement signal.

Various embodiments disclosed herein describe an infrared (IR) imaging system for detecting a gas. The imaging system can include an optical filter that selectively passes light having a wavelength in a range of 1585 nm to 1595 nm while attenuating light at wavelengths above 1600 nm and below 1580 nm. The system can include an optical detector array sensitive to light having a wavelength of 1590 that is positioned rear of the optical filter.

A method of optical spectroscopy for analysing a sample using an optical spectrometer is provided. The method comprises obtaining a sample spectrum of the sample using the optical spectrometer and obtaining a blank spectrum using the optical spectrometer. The blank spectrum comprises structured background radiation which is correlated with the sample spectrum. A cross-correlation of the sample spectrum and the blank spectrum is determined. A mapped blank spectrum is generated by mapping the blank spectrum to the sample spectrum based on the cross-correlation, and the mapped blank spectrum is subtracted from the sample spectrum to generate a background corrected sample spectrum.