Multi-analyte optical computing system
The present subject matter relates to methods of high-speed analysis of product samples. Light is directed to a portion of a product under analysis and reflected from or transmitted through the product toward a plurality of optical detectors. Signals from the detectors are compared with a reference signal based on a portion of the illuminating light passing through a reference element to determine characteristics of the product under analysis. 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 high-speed analysis of product samples, comprising:
illuminating at least a portion of a sample with light at an inspection point;
providing a plurality of light sensitive detectors, the detectors producing outputs based on received light, wherein the detectors are coupled to receive light from the same sample portion and to receive a reference light;
directing light from the sample portion toward a selected one of the plurality of light sensitive detectors through at least one multivariate optical element, the light from the sample portion carrying information about the sample portion;
directing at least a portion of the sample illuminating light toward one of the plurality of light sensitive detectors through a reference optical element to form a reference light, the reference light carrying information about the sample illuminating light;
detecting the reference light in the one of the plurality of light sensitive detectors separately from the light from the sample portion; and
analyzing the signals produced by the detectors, the analysis being based on a comparison of the signals produced from light passing through the at least one multivariate optical element and the signal produced from the reference light.
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 powder 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 illuminating comprises illuminating the sample with a spectral-specific light.
7. The method of claim 6 , 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.
8. The method of claim 1 , wherein the sample comprises a plurality of discrete portions.
9. The method of claim 8 , wherein the plurality of discrete portions are disposed in closed containers, the containers at least partially transparent to the spectral-specific light.
10. The method of claim 1 , wherein directing light from the sample portion toward selected of the plurality of light sensitive detectors through at least one multivariate optical element comprises directing light from the sample portion through a chopper wheel carrying the at least one multivariate optical element.
11. The method of claim 10 , wherein the illuminating source and the plurality of light sensitive detectors are located on a first side of the chopper wheel and the inspection point is located on the opposite side of the chopper wheel.
12. The method of claim 1 , wherein directing light from the sample portion toward a selected one of the plurality of light sensitive detectors comprises directing light through a reflective cone.
13. The method of claim 1 , further comprising:
focusing the light directed from the sample portion on to a selected one of the plurality of light sensitive detectors.
14. The method of claim 13 , wherein focusing comprises directing the light through a lens.
15. The method of claim 13 , wherein focusing comprises directing the light with a focusing mirror.
16. The method of claim 1 , wherein illuminating at least a portion of a sample with light at an inspection point comprises illuminating at least a portion of a sample with focused light.
17. The method of claim 16 , wherein illuminating at least a portion of a sample with focused light comprises illuminating at least a portion of a sample with light reflected from a focusing mirror.
18. The method of claim 1 , wherein the sample includes a mixture of oil and water.
19. The method of claim 1 , wherein the sample includes a mixture of oil and gas.