Spectrum searching method that uses non-chemical qualities of the measurement

Abstract

Methods and systems for determining information about a sample are disclosed. The methods can include measuring spectral information for a sample and determining a quantity related to a signal-to-noise ratio for the spectral information, repeating the measuring and determining until a value of the quantity is beyond a threshold value, and comparing the spectral information to reference information to determine information about the sample.

1 . A method, comprising:
 measuring spectral information for a sample and determining a quantity related to a signal-to-noise ratio for the spectral information;   repeating the measuring and determining until a value of the quantity is beyond a threshold value; and   comparing the spectral information to reference information to determine information about the sample.   
     
     
         2 . The method of  claim 1 , wherein the quantity is a signal-to-noise ratio for the spectral information. 
     
     
         3 . The method of  claim 1 , further comprising combining the measured spectral information with previously measured spectral information prior to determining the quantity. 
     
     
         4 . The method of  claim 1 , further comprising, if an elapsed measurement time exceeds a threshold measurement time, halting further measurement of spectral information. 
     
     
         5 . The method of  claim 1 , further comprising adjusting an operating characteristic of a detection system used to measure the spectral information prior to measuring at least some of the spectral information. 
     
     
         6 . The method of  claim 1 , wherein determining information about the sample comprises at least one of determining an identity of the sample, determining that the sample comprises a mixture of two or more components, and determining that the sample does not comprise any of a plurality of candidates in the reference information. 
     
     
         7 . The method of  claim 1 , wherein comparing the spectral information to reference information comprises determining an extent of overlap between the measured spectral information and reference information corresponding to each of a plurality of candidates. 
     
     
         8 . The method of  claim 7 , wherein the reference information corresponding to each of the candidates comprises an expected distribution of values of the measured spectral information for each candidate. 
     
     
         9 . The method of  claim 8 , further comprising determining the expected distribution of values for each of the candidates based on at least one of an expected noise or error level in a detection system used to measure the spectral information, a temperature of the detection system, a humidity of an environment around the detection system, and a selected distribution. 
     
     
         10 . The method of  claim 8 , wherein determining the extent of overlap comprises determining, for at least some measured values of spectral information displaced from a center of the expected distribution of values by a first distance, a probability that additional measured values of spectral information would be displaced from the center by an amount greater than the first distance. 
     
     
         11 . The method of  claim 3 , further comprising combining only a portion of the measured spectral information with previously measured spectral information prior to determining the quantity. 
     
     
         12 . The method of  claim 1 , wherein determining the quantity related to the signal-to-noise ratio comprises determining one or more uncertainties associated with measured values of the spectral information. 
     
     
         13 . The method of  claim 1 , wherein determining the quantity related to the signal-to-noise ratio comprises determining a probability of identifying the sample based on the reference information. 
     
     
         14 . The method of  claim 1 , wherein determining the quantity related to the signal-to-noise ratio comprises determining a probability that the sample corresponds to a portion of the reference information associated with one or more pure compounds. 
     
     
         15 . A system, comprising:
 a radiation source configured to direct incident radiation to a sample;   a detector configured to measure radiation from the sample; and   an electronic processor configured to:
 determine spectral information for a sample based on the measured radiation; 
 determine a quantity related to a signal-to-noise ratio for the spectral information; 
 repeat the measuring radiation, determining spectral information, and determining the quantity until a value of the quantity is beyond a threshold value; and 
 compare the spectral information to reference information to determine information about the sample. 
   
     
     
         16 . The system of  claim 15 , wherein the electronic processor is configured to combine the spectral information with previously determined spectral information prior to determining the quantity. 
     
     
         17 . The system of  claim 16 , wherein the electronic processor is configured to selectively combine only some of the spectral information with previously determined information prior to determining the quantity. 
     
     
         18 . The system of  claim 15 , wherein the electronic processor is configured to halt further measurement of radiation if an elapsed measurement time exceeds a threshold measurement time. 
     
     
         19 . The system of  claim 15 , wherein the electronic processor is configured to adjust an operating characteristic of the detector prior to measuring at least some of the radiation. 
     
     
         20 . The system of  claim 1 , wherein determining information about the sample comprises at least one of determining an identity of the sample, determining that the sample comprises a mixture of two or more components, and determining that the sample does not comprise any of a plurality of candidates in the reference information. 
     
     
         21 . The system of  claim 1 , wherein determining the quantity related to a signal-to-noise ratio comprises at least one of determining one or more uncertainties associated with measured values of the spectral information, determining a probability of identifying the sample based on the reference information, and determining a probability that the sample corresponds to a portion of the reference information associated with one or more pure compounds. 
     
     
         22 . The system of  claim 1 , wherein the electronic processor is configured to compare the spectral information to reference information by determining an extent of overlap between the spectral information and reference information corresponding to each of a plurality of candidates. 
     
     
         23 . The system of  claim 22 , wherein the reference information corresponding to each of the candidates comprises an expected distribution of values of the spectral information for each candidate. 
     
     
         24 . The system of  claim 23 , wherein the electronic processor is configured to determine the expected distribution of values for each of the candidates based on at least one of an expected noise or error level in the detector, a temperature of the detector, a humidity of an environment around the detector, and a selected distribution. 
     
     
         25 . The system of  claim 23 , wherein the electronic processor is configured to determine the extent of overlap by determining, for at least some values of the spectral information displaced from a center of the expected distribution of values by a first distance, a probability that additional determined values of spectral information would be displaced from the center by an amount greater than the first distance.