Methods for calibrating a multiple detector system

• US 9,442,011 B2
• Filed: 06/01/2015
• Issued: 09/13/2016
• Est. Priority Date: 06/23/2014
• Status: Active Grant

• Current Assignee: Exxonmobil Upstream Research Company (Exxon Mobil Corporation)
• Original Assignee: Exxonmobil Upstream Research Company (Exxon Mobil Corporation)
• Inventors: Morris, Jonathan M., Zeng, Yousheng
• Primary Examiner(s): Porta, David
• Assistant Examiner(s): Maupin, Hugh H
• Application Number:
  US14/727,532
• Publication Number:
  US 20150373285A1
• Time in Patent Office: 470 Days
• US Class Current: 1/1
• CPC Class Codes: G01J 3/28 Investigating the spectrum using colour filters G01J3/51
• CPC Class Codes: G01J 3/2803 using photoelectric array detector
• CPC Class Codes: G01J 3/36 Investigating two or more bands of a spectrum by separate detectors
• CPC Class Codes: G01J 3/42 Absorption spectrometry; Double beam spectrometry; Flicker spectrometry; Reflection spectrometry beam switching arrangements G01J3/08
• CPC Class Codes: G01N 2021/3531 without instrumental source, i.e. radiometric
• CPC Class Codes: G01N 21/274 Calibration, base line adjustment, drift correction
• CPC Class Codes: G01N 21/314 with comparison of measurements at specific and non-specific wavelengths dual wavelength spectrometry G01J3/427
• CPC Class Codes: G01N 21/3504 for analysing gases, e.g. multi-gas analysis

Abstract

Methods for calibrating multiple electromagnetic radiation detectors within a detection system and methods of using such calibrated systems which include generating a calibration electromagnetic radiation beam at a first temperature. At least a portion of the calibration electromagnetic radiation beam is detected with a first electromagnetic radiation detector. An average intensity value of a plurality of pixels from the first electromagnetic radiation detector is obtained. One or more pixels of the first electromagnetic radiation detector are adjusted to decrease the difference between the intensity of an individual pixel and the average intensity value of the first electromagnetic radiation detector. Detecting at least a portion of the calibration electromagnetic radiation beam with a second electromagnetic radiation detector. One or more pixels of the second electromagnetic radiation detector are adjusted to decrease the difference between the intensity of an individual pixel and the average intensity value of the first electromagnetic radiation detector.

Claims

1. A method of calibrating multiple electromagnetic radiation detectors within a detection system comprising:

generating a calibration electromagnetic radiation beam at a first temperature;

detecting at least a portion of the calibration electromagnetic radiation beam with a first electromagnetic radiation detector;

obtaining an average intensity value of a plurality of pixels of the first electromagnetic radiation detector detecting the calibration electromagnetic radiation beam;

adjusting one or more pixels of the first electromagnetic radiation detector to decrease the difference between the intensity of an individual pixel and the average intensity value of the first electromagnetic radiation detector;

detecting at least a portion of the calibration electromagnetic radiation beam with a second electromagnetic radiation detector; and

adjusting one or more pixels of the second electromagnetic radiation detector to decrease the difference between the intensity of an individual pixel and the average intensity value of the first electromagnetic radiation detector.

2. The method of claim 1 further comprising:

passing the calibration electromagnetic radiation beam through a beam splitter to provide a first calibration electromagnetic radiation beam and a second calibration electromagnetic radiation beam;

passing at least a portion of the first calibration electromagnetic radiation beam through a first bandpass filter; and

passing at least a portion of the second calibration electromagnetic radiation beam through a second bandpass filter.

3. The method of claim 1, wherein the calibration electromagnetic radiation beam is obtained using a black body electromagnetic radiation source.

4. The method of claim 1, wherein the first temperature is between about minus 50°

C. to about 200°

C.

5. The method of claim 1 further comprising:

generating an additional calibration electromagnetic radiation beam at a second temperature;

detecting at least a portion of the additional calibration electromagnetic radiation beam with a first electromagnetic radiation detector;

obtaining an average intensity value of the plurality of pixels of the first electromagnetic radiation detector detecting the additional calibration electromagnetic radiation beam;

adjusting one or more pixels of the first electromagnetic radiation detector to decrease the difference between the intensity of an individual pixel and the average intensity value of the first electromagnetic radiation detector;

detecting at least a portion of the additional calibration electromagnetic radiation beam with a second electromagnetic radiation detector; and

adjusting one or more pixels of the second electromagnetic radiation detector to decrease the difference between the intensity of an individual pixel and the average intensity value of the first electromagnetic radiation detector.

6. The method of claim 5, wherein the second temperature is between about 20°

C. to about 100°

C. and is different from the first temperature.

7. The method of claim 1, wherein the calibration electromagnetic radiation is mid-wave infrared radiation.

8. The method of claim 1, wherein the first electromagnetic radiation detector comprises a first focal plane array and the second electromagnetic radiation detector comprises a second focal plane array.

9. The method of claim 1, wherein the intensity of a majority of the plurality of pixels of the first electromagnetic radiation detector and a majority of the plurality of pixels of the second electromagnetic radiation detector are substantially the same as the average intensity value for the first electromagnetic radiation detector.

10. The method of claim 1, wherein the difference between the plurality of pixels of the first electromagnetic radiation detector and the average intensity value of the first electromagnetic radiation detector is within 5% of the dynamic range of the first electromagnetic radiation detector.

11. The method of claim 1, wherein the difference between the plurality of pixels of the second electromagnetic radiation detector and the average intensity value of the first electromagnetic radiation detector is within 5% of the dynamic range of the second electromagnetic radiation detector.

12. The method of claim 2, wherein the first bandpass filter has a first transmittance window having a first width between a lower limit wavelength value and an upper limit wavelength value and the second bandpass filter has a second transmittance window having a second width between a lower limit wavelength value and an upper limit wavelength value such that the lower limit wavelength value and the upper limit wavelength value of the second transmittance window is outside of the lower limit wavelength value and the upper limit wavelength value for the first transmittance window.

13. The method of claim 1, wherein the difference between the intensity of an individual pixel and the average intensity value of the first electromagnetic radiation detector is decreased by adjusting the gain of the individual pixel.

14. The method of claim 1, wherein the difference between the intensity of an individual pixel and the average intensity value of the first electromagnetic radiation detector is decreased by adjusting the offset of the individual pixel.

15. A method of detecting at least one chemical species comprising:

calibrating a detection system including multiple electromagnetic radiation detectors according to claim 1; and

using the calibrated detection system to determine the presence of at least one chemical species.

16. The method of claim 15, wherein the at least one chemical species originates from a release into the environment.