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Spectral Peak Location by Inverted, Truncated Second Derivative of Spectra

IP.com Disclosure Number: IPCOM000085018D
Original Publication Date: 1976-Feb-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Anderson, RM: AUTHOR

Abstract

Procedures for locating peaks in spectra produced by a wide variety of analytical machines are sensitive to noise and, quite often, miss weak peaks or very closely spaced peaks. It has been found that these deficiencies may be overcome through the use of a manipulated, inverted second derivative spectrum.

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Spectral Peak Location by Inverted, Truncated Second Derivative of Spectra

Procedures for locating peaks in spectra produced by a wide variety of analytical machines are sensitive to noise and, quite often, miss weak peaks or very closely spaced peaks. It has been found that these deficiencies may be overcome through the use of a manipulated, inverted second derivative spectrum.

The problem to be addressed is the determination of peak locations in X-ray and related spectra. In the past, peaks were found by sampling the data points in the spectrum and either: 1) comparing adjacent points and seeing where a train of ascending points begin to descend, marking a peak, or 2) taking the first derivative of the spectra and counting zero crossings.

Both of these methods are sensitive to noise and the locations of the peaks found must be statistically examined, to see if the signal-to-noise ratio of the located peaks yield true or noise peaks.

Also neither method resolves peaks which are overlapped to the point where a second peak appears only as a point of inflection on the side of a neighboring large peak.

The following discussion refers to the figure. The raw spectra appears at (A) the same spectra is at (B) after a smoothing operation.

The spectra at (C) is the (B) spectra after taking the second derivative of the spectra. Note that a negative going peak exists at each peak in (B) including the points-of-inflection peaks. At (D) the (C) spectra is inverted and truncat...