Spectroscopic analysis

• US 10,352,768 B2
• Filed: 03/14/2018
• Issued: 07/16/2019
• Est. Priority Date: 06/19/2012
• Status: Active Grant

• Current Assignee: Klein Medical Ltd.
• Original Assignee: Klein Medical Ltd.
• Inventors: Simpkin, Raymond Andrew, Krouse, Donal Paul, Smith, Bryan James
• Primary Examiner(s): Kim, Kiho
• Application Number:
  US15/921,517
• Publication Number:
  US 20180313691A1
• Time in Patent Office: 489 Days
• CPC Class Codes: G01J 3/0297 Constructional arrangements for removing other types of optical noise or for performing calibration
• CPC Class Codes: G01J 3/108 for measurement in the infrared range
• CPC Class Codes: G01J 3/28 Investigating the spectrum using colour filters G01J3/51
• CPC Class Codes: G01N 21/274 Calibration, base line adjustment, drift correction
• CPC Class Codes: G01N 21/3577 for analysing liquids, e.g. polluted water
• CPC Class Codes: G01N 21/359 using near infrared light
• CPC Class Codes: G01N 2201/0691 Modulated (not pulsed supply)

Abstract

A method and analyzer for identifying or verifying or otherwise characterizing a sample comprising: using or having an electromagnetic radiation source for emitting electromagnetic radiation in at least one beam at a sample, the electromagnetic radiation comprising at least two different wavelengths, using or having a sample detector that detects affected electromagnetic radiation resulting from the emitted electromagnetic radiation affected by the sample and provides output representing the detected affected radiation, and using or having a processor for determining sample coefficients from the output, and identifying or verifying or otherwise characterizing the sample using the sample coefficients and training coefficients determined from training samples, wherein the coefficients reduce sensitivity to a sample retainer variation and/or are independent of concentration.

Claims

1. An analyser for identifying or verifying or otherwise characterising a sample, the analyser comprising:

an electromagnetic radiation source for emitting electromagnetic radiation in at least one beam at a sample, the electromagnetic radiation comprising at least two different wavelengths;

a sample detector that detects affected electromagnetic radiation resulting from the emitted electromagnetic radiation affected by the sample and provides output representing the detected affected radiation;

a processor for determining sample coefficients from the output and identifying or verifying or otherwise characterising the sample using the sample coefficients and training coefficients determined from training samples; and

a temperature sensor to measure the temperature of the sample and provide temperature output to the processor, wherein the processor corrects spectral components of the training coefficients at the at least two wavelengths based on the temperature of the sample.

2. An analyser according to claim 1, wherein the sample detector output represents intensities detected by the detector at the at least two wavelengths, and wherein determining the sample coefficients comprises deteimining and using a fractional spectral intensity at each wavelength.

3. An analyser according to claim 2, further comprising a reference detector for detecting reference electromagnetic radiation at the at least two wavelengths that provides output representing intensities detected at the at least two wavelengths, and the fractional spectral intensity at each wavelength is a normalised fractional spectral intensity using the output from the reference detector.

4. A analyser according to claim 3, wherein the analyser is used on a plurality of training samples to obtain from the sample detector training output for a plurality of training samples representing intensities detected by the detector at the at least two wavelengths, and wherein the processor is configured to determine the training coefficients by determining and using a fractional spectral intensity at each wavelength of the training output.

5. An analyser according to claim 4, wherein the fractional spectral intensity is a normalised fractional spectral intensity using output from a reference detector.

6. An analyser according to claim 5, wherein the fractional intensity is defined as the proportion of transmitted light measured at a wavelength referenced to the sum of intensities over all the at least two wavelengths.

7. An analyser according to claim 1, wherein the temperature is corrected according to:

8. A method for identifying or verifying or otherwise characterising a sample, the method comprising:

emitting electromagnetic radiation from an electromagnetic radiation source in at least one beam at a sample, the electromagnetic radiation comprising at least two different wavelengths;

using a sample detector, detecting affected electromagnetic radiation resulting from the emitted electromagnetic radiation affected by the sample and providing detected output representing the detected affected radiation;

using a processor, determining sample coefficients from the output; and

using the processor, identifying or verifying or otherwise characterising the sample using the sample coefficients and training coefficients determined from training samples,

wherein a temperature of the sample is measured using a temperature sensor and used to correct spectral components of the training coefficients at the at least two wavelengths based on the temperature of the sample.

9. A method according to claim 8, wherein the detected output represents intensities detected at the at least two wavelengths, and wherein determining the sample coefficients comprises determining and using a fractional spectral intensity at each wavelength.

10. A method according to claim 9, further comprising detecting, using a reference detector, reference electromagnetic radiation at the at least two wavelengths and providing output representing intensities detected at the at least two wavelengths, and the fractional spectral intensity at each wavelength is a normalised fractional spectral intensity using the output from the reference detector.

11. A method according to claim 10, further comprising:

for a plurality of training samples, emitting electromagnetic radiation from the electromagnetic radiation source or a second electromagnetic radiation source in at least one beam at each training sample, the electromagnetic radiation comprising at least two different wavelengths;

for each training sample, using the sample detector or a second detector, detecting affected electromagnetic radiation resulting from the emitted electromagnetic radiation affected by the training sample and providing detected output representing the detected affected radiation; and

for each training sample, using the processor or a second processor, determining training coefficients from the output by determining and using a fractional spectral intensity at each wavelength of the training output.

12. A method according to claim 11, wherein the fractional intensity is defined as the proportion of transmitted light measured at a wavelength referenced to the sum of intensities over all the at least two wavelengths.

13. A method according to claim 10, wherein the fractional spectral intensity is a normalised fractional spectral intensity using output from a reference detector.

14. A method according to claim 8, wherein the temperature is corrected according to:

15. A method for identifying or verifying or otherwise characterising a sample comprising:

emitting electromagnetic radiation from an electromagnetic radiation source in at least one beam at a sample, the electromagnetic radiation comprising at least two different wavelengths;

using a first detector, detecting the emitted electromagnetic radiation at each wavelength and providing detected output representing the emitted electromagnetic radiation being reference intensity detected at each wavelength;

using the first detector or a second detector, detecting affected electromagnetic radiation resulting from the emitted electromagnetic radiation affected by the sample and providing detected output representing the detected affected radiation being output intensity detected at each wavelength;

measuring the temperature of the sample using a temperature sensor;

using a processor, determining sample coefficients from the output; and

using the processor, identifying or verifying or otherwise characterising the sample using the sample coefficients and training coefficients determined from training samples, wherein determining the sample coefficients comprises;

using the processor, eliminating dark current from the output of the reference and output intensities;

using the processor, determining fractional spectral intensities from the reference and output intensities;

using the processor, determining a concentration independent coefficient from the fractional spectral intensities,

wherein the training coefficients have been determined from data temperature corrected to the temperature of the sample.