Method and apparatus for measuring absorption coefficient of a medium
AssigneeBarriq Inc.
InventorRafael I. Aldaz
Life of this patent
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Abstract
The present invention discloses a method to optically measure the absorption coefficient of a liquid or gas medium, without affecting the medium. Such absorption spectrum can be utilized to quantify the chemical components of the medium, or other metrics such as color or signature of the medium. The method acknowledges the possible drifts in the optical components of the system with time and measures the absorption coefficient independently of the state of the optical components. Therefore, there is no need to calibrate the system or take reference measurements. The method presented can be implemented cost effectively, designed in compact systems, and is energy efficient, thus, meeting the stringent challenges of spaced constrained remote systems such as aging wine barrels.
Claims9
A method of measuring an absorption coefficient of a medium across a light spectrum of wavelengths, the method comprising:
- setting a first optical path length L1 as the total length a specific light traverses the medium;
- for L1, measuring a first light output intensity I0_1 for each wavelength of interest across a spectrum of said specific light that traverses the medium for length L1, thereby creating a first I0_1 data set;
- setting a second optical path length L2 as the total length the specific light traverses the medium;
- for L2, measuring a second light output intensity I0_2 for each wavelength of interest across the spectrum of said specific light that traverses the medium for length L2, thereby creating a second I0_2 data set;
- calculating the natural log for each I0 from the first I0_1 data set corresponding to length L1, thereby creating a third data set;
- calculating the natural log for each I0 from the second I0_2 data set corresponding to length L2, thereby creating a fourth data set;
- and
- fitting data from the third data set for each wavelength and data from the fourth data set for each wavelength to a linear function line of the natural log of a light intensity versus length, L, wherein a slope of the linear function line indicates the absorption coefficient of the medium and an intercept point where the linear function line intercepts a vertical axis conveys data relating to one or more variables, wherein the one or more variables are independent of absorption coefficient measurement.
Dependencies are inferred from the claim text.