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 an optical detector. Signals for the detector are compared with reference signals 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:
transmitting an illumination light through a analyte multivariate optical element to form an analyte light, the multivariate optical element being positioned on a chopper wheel;
illuminating a sample at an inspection point with the analyte light;
transmitting the illumination light through a reference optical element to form a reference light different from the analyte light, the reference optical element being positioned on the chopper wheel and configured to correspond to the multivariate optical element;
illuminating the sample with the reference light;
providing a light sensitive detector, the detector producing an output signal based on received light;
directing light from the sample toward the light sensitive detector, the light from the sample carrying information about the sample; and
analyzing output signals produced by the detector, the analysis being based on a comparison of an output signal produced by the analyte light and an output signal produced by 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 illumination 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 comprises directing light reflected from the sample.
6. The method of claim 1 , wherein directing light from the sample comprises directing light transmitted through the sample.
7. The method of claim 1 , wherein illuminating the sample with the analyte light 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 , wherein:
transmitting the illumination light through the analyte multivariate optical element comprises directing the illumination light through a plurality of multivariate optical elements; and
transmitting the illumination light through the reference optical element comprises directing the illumination light through a plurality of reference optical elements.
12. The method of claim 11 , wherein the illumination light is transmitted alternately through differing multivariate optical elements and corresponding reference optical elements in sequence.
13. The method of claim 1 further comprising determining a specific property of an analyte in the sample associated with the multivariate optical element and the reference optical element.
14. The method of claim 13 wherein the analyte includes a gasoline.
15. The method of claim 14 wherein the specific property of the analyte is an octane rating of the gasoline.
16. A system for high-speed analysis of samples comprising:
an illumination source to provide an illumination light to at least a sample at an inspection point, the sample comprising at least one analyte;
a light sensitive detector to produce an output based on a received light;
a chopper wheel comprising:
a multivariate optical element placed between the illumination source and the sample; and
a reference optical element placed between the illumination source and the sample, wherein the reference optical element corresponds to the multivariate optical element; and
an optical element to direct light from the sample to the light sensitive detector;
wherein the multivariate optical element and the reference optical element are selected for measurement of a specific property of the analyte, and for illuminating the sample with an analyte light different from a reference light.
17. The system of claim 16 further comprising a plurality of multivariate optical elements, each of the plurality of optical elements associated with a reference optical element, the multivariate optical element and the reference optical element selected to measure a specific property of the analyte.
18. The system of claim 16 wherein the analyte comprises at least a gasoline sample.
19. The system of claim 18 wherein the specific property is an octane rating of the gasoline sample.