Optical Absorbance Measurements With Self-Calibration And Extended Dynamic Range
AssigneeSpectraSensors, Inc.
InventorsXin Zhou, Xiang Liu, Alfred Feitisch
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Abstract
Detector data representative of an intensity of light that impinges on a detector after being emitted from a light source and passing through a gas over a path length can be analyzed using a first analysis method to obtain a first calculation of an analyte concentration in the volume of gas and a second analysis method to obtain a second calculation of the analyte concentration. The second calculation can be promoted as the analyte concentration upon determining that the analyte concentration is out of a first target range for the first analysis method.
Claims20
A method comprising:
- receiving, at a processor, detector data representative of an absorbance of light emitted from a light source as the light passes through a volume of gas over a path length, the volume of gas comprising an analyte at an analyte concentration;
- analyzing the detector data using a first analysis method to obtain a first calculation of the analyte concentration, the first analysis method having a first target range;
- analyzing the detector data using a second analysis method to obtain a second calculation of the analyte concentration, the second analysis method having a second target range that differs from and extends outside of the first target range;
- determining that the first calculation of the analyte concentration indicates that the analyte concentration is outside of the first target range;
- and
- promoting the second calculation as the analyte concentration.
A method comprising:
- receiving, at a processor, detector data representative of absorbances of light emitted from a light source as the light passes through a volume of gas over a path length, the volume of gas comprising an analyte at an analyte concentration and a background compound at a background compound concentration, the absorbances comprising a target absorbance influenced by the analyte concentration and the background gas concentration and a reference absorbance influenced by the background gas concentration;
- analyzing the detector data using a direct absorbance method to obtain a first metric representative of the reference absorbance;
- analyzing the detector data using a modulation spectroscopy method to obtain a second metric representative of the target absorbance;
- adjusting the second metric using the first metric to estimate a contribution to the second metric due to the analyte concentration;
- determining the analyte concentration based on the contribution to the second metric due to the analyte concentration;
- and
- promoting the analyte concentration.
A system comprising a machine-readable medium storing instructions that, when executed by at least one processor, cause the at least one processor to perform operations comprising:
- receiving, at a processor, detector data representative of an absorbance of light emitted from a light source as the light passes through a volume of gas over a path length, the volume of gas comprising an analyte at an analyte concentration;
- analyzing the detector data using a first analysis method to obtain a first calculation of the analyte concentration;
- analyzing the detector data using a second analysis method to obtain a second calculation of the analyte concentration, the second analysis method having a second target range that differs from and extends outside of the first target range;
- determining that the first calculation of the analyte concentration indicates that the analyte concentration is outside of a first target range for the first analysis method;
- and
- promoting the second calculation as the analyte concentration.
A system as in claim 17, further comprising the at least one processor.
Dependencies are inferred from the claim text.