Signal processing for optical computing system
The present subject matter relates to methods of high-speed analysis of product samples during production of the product. Light is directed to a portion of a product under analysis and reflected from or transmitted through the product toward optical detectors. Signals from the optical detectors are compared to determine characteristics of the product under analysis. Temperature within the monitoring system may be monitored in order to provide compensation for the signals produced by the optical detectors. The products under analysis may be stationary, moved by an inspection point by conveyor or other means, or may be contained within a container, the container including a window portion through which the product illuminating light may pass.
1. A method for downhole analysis of samples in a wellbore, comprising:
providing an illumination source downhole;
illuminating with a portion of the light from the illuminating source at least a portion of a sample with light at an inspection point;
providing first and second light sensitive detectors, the detectors producing output signals based on received light;
directing a portion of the light from the illuminated sample portion toward the first and second light sensitive detectors, the light from the illuminated sample portion carrying information about the sample portion;
directing at least a portion of the light from the illumination source toward the first and second light sensitive detectors as a reference light;
providing a temperature sensor in proximity to the first and second light sensitive detectors, the temperature sensor producing an output signal based on temperature;
compensating the output signals produced by the first and second detectors based on the temperature output signal; and
analyzing the compensated output signals produced by the first and second light sensitive detectors to determine temperature compensated illuminated sample portion information.
2. The method of claim 1 , wherein the sample is at least one of a pharmaceutical tablet, a pharmaceutical powder, a food material, a chemical, a liquid, a gas, an emulsion, a solution, or a mixture thereof.
3. The method of claim 1 , wherein the sample is a hydrocarbon mixture in a closed container, the container being at least partially transparent to the illuminating light.
4. The method of claim 1 , further comprising: moving the sample past the inspection point.
5. The method of claim 1 , wherein directing light from the sample portion comprises directing light reflected from the sample portion.
6. The method of claim 1 , wherein directing light from the sample portion comprises directing light transmitted through the sample portion.
7. The method of claim 1 , wherein illuminating comprises illuminating the sample with a spectral-specific light.
8. The method of claim 7 , further comprising: illuminating the sample through an optic window, the optic window being configured to focus the spectral-specific light onto a sample portion at the inspection point.
9. The method of claim 1 , wherein the sample comprises a plurality of discrete portions.
10. The method of claim 9 , wherein the plurality of discrete portions are disposed in closed containers, the containers at least partially transparent to the spectral-specific light.
11. The method of claim 1 , further comprising passing light directed toward one of the light sensitive detectors through a multivariate optical element.
12. The method of claim 1 , further comprising modulating light from the illumination source.
13. The method of claim 1 , further comprising creating a vacuum around the light sensitive detectors and measuring the temperature within the vacuum.
14. The method of claim 1 , further comprising splitting the directed light from the illuminated sample into two sample beams, and directing one sample beam to the first detector and the other sample beam to the second detector.
15. The method of claim 14 , further comprising:
splitting the reference light into two reference beams, and directing one reference beam to the first detector and the other reference beam to the second detector; and
passing one reference beam and one sample beam through a multivariate optical element.
16. A method for downhole analysis of samples in a wellbore, comprising:
providing an illumination source downhole;
illuminating with a portion of the light from the illuminating source at least a portion of a sample at an inspection point;
providing first and second light sensitive detectors, the detectors producing output signals based on received light;
splitting a portion of the light reflected from the illuminated sample into two sample beams, the light from the illuminated sample carrying information about the sample;
directing one sample beam to the first light sensitive detector and the other sample beam to the second light sensitive detector;
passing one of the sample beams directed towards a light sensitive detector through a multivariate optical element;
directing at least a portion of the light from the illumination source toward the first and second light sensitive detectors as a reference light;
providing a temperature sensor in proximity to the first and second light sensitive detectors, the temperature sensor producing an output signal based on temperature;
compensating the output signals produced by the first and second detectors based on the temperature output signal; and
analyzing the compensated output signals produced by the first and second light sensitive detectors to determine temperature compensated illuminated sample information.
17. The method of claim 16 , further comprising creating a vacuum around the light sensitive detectors and measuring the temperature within the vacuum.
18. The method of claim 16 , further comprising:
splitting the reference light into two reference beams, and directing one reference beam to the first detector and the other reference beam to the second detector; and
passing one reference beam through a multivariate optical element.
19. The method of claim 18 , further comprising modulating light from the illumination source.