Raman signal position correction using relative integration parameters

Abstract

The present invention relates to Raman signal position correction using relative integration parameters. An improved method for integrating curve peaks as compared to techniques such as the trapezoidal rule wherein integration parameters are at fixed x-axis positions. Integration parameters are instead specified relative to a peak center, which allows the peak to shift over time due to hardware changes, temperature fluctuation, pressure changes, etc., while maintaining integration parameters at optimal locations for that peak. As such, the present disclosure finds particular utility in spectroscopy wherein, in the case of Raman spectroscopy, for example, specific wavenumber shift locations may drift over time, leading to inaccurate results based upon absolute integration parameters.

Description

technical field [0001] The present disclosure relates generally to curve integration, and in particular to an integration method that uses relative rather than absolute integration parameters. Background technique [0002] A common operation in signal processing is signal integration. This manipulation can be depicted by a graph, where the x-axis represents time or parameters affecting the signal strength which can be referred to as the y-axis response, as figure 1 shown in . To recover the entire signal, the bins along the x-axis are summed over the y-axis signal intensities. This type of integral is often called the "trapezoidal rule". [0003] Another method for integration is through the use of curve fitting. In this method, as figure 2 As shown in , segments of intensity along the x-axis are examined, and a mathematical formula is used to iteratively form a combination curve matching the shape of the signal 202 . Curve area 208 is then determined by summing the a...

AI Technical Summary

Problems solved by technology

Specific to Raman spectroscopy, the excitation laser wavelength (i.e., wavenumber) may drift with time

In addition to these instrumental effects, the molecular nature of Raman spectroscopy can also cause peak shifts due to changes in composition in the mixture and / or changes in the temperature of the sample

In common signal integration, the baseline and integration limits are held constant, but peaks may shift relative to the integration limits to the extent that the integration limits are no longer optimal, leading to errors in determining the concentrations of components of the sample under test

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