Adaptive Method for Outlier Detection and Spectral Library Augmentation

• US 20090012723A1
• Filed: 08/22/2008
• Published: 01/08/2009
• Est. Priority Date: 06/09/2005
• Status: Abandoned Application

• Current Assignee: Chemimage Corporation
• Original Assignee: Chemimage Corporation
• Inventors: TREADO, Patrick J., Schweitzer, Robert, Neiss, Jason
• Application Number:
  US12/196,921
• Publication Number:
  US 20090012723A1
• Time in Patent Office: Days
• US Class Current: 702/28
• CPC Class Codes: G16C 20/20 Identification of molecular entities, parts thereof or of chemical compositions
• CPC Class Codes: G16C 20/90 Programming languages; Computing architectures; Database systems; Data warehousing

Abstract

A method for analyzing data from an unknown substance, whereby target data representative of an unknown substance is received and compared to reference data associated with one or more known substances. Such comparison determines one or more candidate substances. After determining candidate substances, it is determined if the target data is unique to a candidate substance. If the target data is unique to one of the candidate substances, then this determination is confirmed with fusion. If the target data is not unique, then the target data may be subjected to fusion and unmixing with fusion. If analysis of the target data determines that an outlier is present, then this target data is added to a pool of unassigned data. The addition of this new data to the pool of unassigned data may result in clustering of enough of the previously unassigned data to form a new candidate class. If analysis of the target data does not detect an outlier, but cannot be matched to an existing candidate class, the target data in this case can also be added to the pool of unassigned data. If no outlier is detected, and the Matching Existing Class step is successful, then the target data is added to the matched class. If this candidate class is confirmed, then it can be added to the list of existing classes.

Claims

1. A method for analyzing data from an unknown substance, comprising the steps of:

(a) receiving first target data representative of said unknown substance from a first data gathering modality and second target data representation of said unknown substance from a second data gathering modality;

(b) comparing said first target data with reference data associated with one or more known substances to thereby determine one or more candidate substances;

(c) determining if said first target data is unique to one of said candidate substances;

(i) if unique, comparing said second target data with said reference data;

(A) if the comparison of said second target data with said reference data confirms the determination of uniqueness, identify said unknown substance;

(B) if the comparison of said second target data with said reference data does not confirm the determination of uniqueness, performing an unmixing process using said first and second target data and identifying said unknown substance if the unmixing process results in a confirmation of the determination of uniqueness;

(ii) if not unique, comparing said second target data with said reference data;

(A) if the comparison of said second target data with said reference data results in a determination of uniqueness, identify said unknown substance;

(B) if the comparison of said second target data with said reference data does not result in a determination of uniqueness, performing an unmixing process using said first and second target data and identifying said unknown substance if the unmixing process results in a confirmation of the determination of uniqueness;

(d) if the comparison of said first target data with said reference data does not result in determining one or more candidate substances, performing an unmixing process using said first and second target data and identifying said unknown substance if the unmixing process results in a determination of a candidate substance.

2. The method of claim 1 further comprising performing one or more sensor diagnostic tests.

3. The method of claim 2 wherein said sensor is selected from the group consisting of:

a Raman sensor, a near infrared sensor, a fluorescence sensor or a laser induced breakdown spectroscopy sensor, and combinations thereof.

4. The method of claim 1 further comprising performing initial data validation.

5. The method of claim 1 wherein said first data gathering modality and said second data generating modality are instruments selected from the group consisting of:

a Raman spectrometer, a mid-infrared spectrometer, an x-ray diffractometer, an energy dispersive x-ray analyzer, a mass spectrometer, a microscope, image generating instrument, chromatographic analyzer, charge-coupled detector, and combinations thereof.

6. The method of claim 1 wherein said comparing of step (b) is performed by at least one of the following:

mahalanobis distance, partial least squares regression, support vector machines, linear discriminant analysis, maximum likelihood estimation, Bayesian classification, neutral networks, hidden markov models, or k-nearest neighbors.

7. The method of claim 1 wherein said unmixing is performed by at least one of the following:

target factor analysis, spectral mixture resolution, vector component analysis, independent component analysis, or family of least squares operators.

8. The method of claim 1 wherein said reference data comprises noise-degraded data.

9. A method for analyzing data from an unknown substance, comprising the steps of:

(a) receiving target data representative of said unknown substance;

(b) determining from said target data whether said unknown substance is an outlier;

(i) if said unknown substance is determined to be an outlier, assigning said target data to a pre-existing first pool of data representing one or more unidentified substances to thereby form a second pool of data;

(ii) analyzing said second pool of data to determine if a subgroup of said second pool of data represents a candidate substance; and

(iii) identifying said subgroup of data as said candidate substance; and

(c) if said unknown substance is determined to not be an outlier, comparing said target data with reference data associated with one or more candidate substances;

(i) if the comparison of said target data with said reference data does not result in matching said unknown substance with said one or more candidate substances, assigning said target data to said pre-existing first pool of data;

(ii) if the comparison of said target data with said reference data results in matching said unknown substance with a first candidate substance;

(A) adding said target data to said reference data associated with said first candidate substance;

(B) analyzing second target data to thereby confirm said candidate substance as a known substance; and

(C) adding said candidate substance to a pre-existing list of known substances.

10. The method of claim 9 wherein said target data is received from an instrument selected from the group consisting of:

a Raman spectrometer, a mid-infrared spectrometer, an x-ray diffractometer, an energy dispersive x-ray analyzer, a mass spectrometer, a microscope, image generating instrument, chromatographic analyzer, charge-coupled detector, and combinations thereof.

11. The method of claim 9 wherein a Reed-Xu algorithm is used in step (b) to determine if said unknown substance is an outlier.

12. The method of claim 9 wherein said comparing of step (c) is performed by at least one of the following:

mahalanobis distance, partial least squares regression, support vector machines, linear discriminant analysis, maximum likelihood estimation, Bayesian classification, neutral networks, hidden markov models, or k-nearest neighbors.

13. The method of claim 9 wherein step (c) further comprises the steps of:

(a) determining one or more candidate substances from said comparison;

(b) determining if said first target data is unique to one of said candidate substances;

(i) if unique, comparing said second target data with said reference data;

(A) if the comparison of said second target data with said reference data confirms the determination of uniqueness, identify said unknown substance;

(B) if the comparison of said second target data with said reference data does not confirm the determination of uniqueness, performing an unmixing process using said first and second target data and identifying said unknown substance if the unmixing process results in a confirmation of the determination of uniqueness;

(ii) if not unique, comparing said second target data with said reference data;

(A) if the comparison of said second target data with said reference data results in a determination of uniqueness, identify said unknown substance;

(B) if the comparison of said second target data with said reference data does not result in a determination of uniqueness, performing an unmixing process using said first and second target data and identifying said unknown substance if the unmixing process results in a confirmation of the determination of uniqueness.

14. The method of claim 13 wherein said comparing is performed by at least one of the following:

mahalanobis distance, partial least squares regression, support vector machines, linear discriminant analysis, maximum likelihood estimation, Bayesian classification, neutral networks, hidden markov models, or k-nearest neighbors.

15. The method of claim 13 wherein said unmixing is performed by at least one of the following:

target factor analysis, spectral mixture resolution, vector component analysis, independent component analysis, or family of least squares operators.