Patent ID: 8823939

Claim:
A method of determining a characteristic of a sample, comprising: optically interacting an electromagnetic radiation source with the sample and a first integrated computational element arranged within a primary channel and a second integrated computational element arranged within a reference channel, wherein the first and second computational elements are configured to be positively or negatively correlated to the characteristic of the sample; producing first and second modified electromagnetic radiations from the first and second integrated computational elements, respectively, wherein, when a resulting signal from the first modified electromagnetic radiation increases with an increased sample characteristic, a resulting signal from the second modified electromagnetic radiation decreases, and wherein, when the resulting signal from the first modified electromagnetic radiation decreases with the increased sample characteristic, the resulting signal from the second modified electromagnetic radiation increases; receiving the first and second modified electromagnetic radiations with a first detector; and generating an output signal with the first detector, the output signal corresponding to the characteristic of the sample.