Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Reexamination Certificate
2001-02-13
2004-09-14
Bruce, David V. (Department: 2882)
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
C702S040000, C702S155000
Reexamination Certificate
active
06791075
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method of spectrum analysis in two-dimensional representation to obtain accurate characteristic information on an object to be analyzed by using derivatives on spectral data of the said object in spectroscopic analysis.
DESCRIPTION OF THE PRIOR ART
Heretofore, in spectroscopic analysis (including infrared spectrophotometry and the like) in general, by measuring an intensity of light transmitting through the object to be analyzed(may hereafter be denoted as “analyzed object”) and converting absorbance, various characteristics or information in terms of physical and/or chemical properties (may hereafter be denoted as “characteristic information”) including shapes, concentration, and the like of substances contained in the said analyzed object have been obtained based on the shapes of the said spectrum or a spectral profile. As such a conventional spectral profile, that spectral profile representing absorbance of the analyzed object in terms of the wavenumber (or wavelength) are generally used (may hereafter be referred to as “absorbance/wavenumber spectral profile”). It can be considered that such a spectral profile is formed with a number of component bands overlapped.
As a means to analyze such spectral profiles, for example, the Japanese patent publication H11-148865 discloses the method of using derivatives on the spectral waveform of the analyzed object in spectroscopic analysis. To be concrete, as for the specific analyzed object, when spectral waveform where the intensity of the signal output of a spectrophotometer is represented as a function of wavenumber, wavelength, or time is prepared letting n1 and n2 (n1≠n2) be a positive integer, a method of spectrum analysis in two-dimensional representation with the following characteristics is disclosed. These characteristics are;
Calculating the n1-th and n2-th derivatives with respect to wavenumber, wavelength, or time of the said intensity of the signal output regarding the spectral profile on the said spectral data, plotting points on the two-dimensional coordinate plane whose X-coordinate is the said n1-th derivative and whose Y-coordinate is the said n2-th derivative, respectively, on the said two-dimensional coordinate plane, creating a two-dimensional plot of derivative pairs on the said spectral waveform, thereby obtaining specific information on the said spectral profile based on the two-dimensional plot of the said derivative pairs.
However, although the spectral analysis method cited in the Japanese patent publication H11-148865 can find component bands when the spectral profile contains a (single) component band, it is difficult to find all these component bands and even to estimate them is extremely difficult when the spectral profile of the analyzed object contains several component bands overlapped. In particular, there are many cases that the spectral profile of the analyzed object has several overlapping component bands. Therefore, as for the analyzed object with a spectral profile containing several component bands, the method described in the Japanese patent publication H11-148865 can estimate the dominant component bands to some extent among the said component bands. However, as for unresolved bands buried under the dominant band, that is, the characteristics of those component bands are unclear due to severe overlap, it is extremely difficult even to estimate those bands.
SUMMARY OF THE INVENTION
Based on the method cited in the Japanese patent publication H11-148865, the present invention has been developed for further improvement. As a result of intensive studies, as for the specific analyzed object, when spectral data where the intensity of the signal output of a spectrophotometer is represented as a function of wavenumber, wavelength, or time, are prepared letting n and m (nwm) be a positive integer, the inventor has proposed a method of spectrum analysis in two-dimensional representation for obtaining the specific characteristic information on the said spectral data based on the said two-dimensional derivative plot by calculating the n-th and m-th derivatives with respect to wavenumber, wavelength, or time, of the said spectral data, plotting points on the two-dimensional coordinate plane as the X-Y coordinate system whose X-coordinate is the said n-th derivative and whose Y-coordinate is the said m-th derivative respectively on the said two-dimensional coordinate plane, and preparing the two-dimensional derivative plot on the said spectral data.
Further, based on the characteristic information described above, the inventor has proposed a method of spectrum analysis in two-dimensional representation which estimates the component bands comprising the spectral profile of the analyzed object by estimating band parameter values regarding at least one component band among the component bands contained in the spectral profile of the analyzed object, estimating at least one component band, obtaining the two-dimensional derivative plot with the specific remaining component bands removed by clearing the specific component band or specific component bands already estimated or the two-dimensional derivative plot from spectral profiles or the two-dimensional derivative plot of analyzed object, obtaining specific characteristic information based on the two-dimensional derivative plot of this specific component removed, estimating band parameter values on other component bands based on the said characteristic information, and iterating the estimation of at least one of the other component bands thereby estimating component bands in order.
That is, the present invention is a method of estimating component bands in order, using a specific component band or specific component bands already estimated and estimating remaining component bands (including the ones not yet estimated, the ones desired to be optimal).
To be concrete, a preferred embodiment of the present invention, although not specifically limited, is, first of all, to estimate one component band BDi(i is a positive integer) by estimating the band parameter values for BDi among component bands contained in the spectral profile of the analyzed object based on the specific characteristic information on the spectral profile of the two-dimensional derivative plot.
Next, the preferred embodiment is to prepare the two-dimensional derivative plot with BDi removed, either creating the two-dimensional derivative plot with BDi removed by clearing the two-dimensional derivative plot of the component band BDj (j is a positive integer where j≠i) from the two-dimensional derivative plot of the said analyzed object or obtaining the spectral profile with BDi removed by clearing a profile of BDi from a spectral profile of the said analyzed object.
Then, the preferred embodiment is to estimate one component band BDj by estimating band parameter values on BDj other than BDi among the component bands contained in the spectral profile of the analyzed object based on the said characteristic information by obtaining the specific characteristic information based on the said two-dimensional derivative plot with BDi removed.
Next, the preferred embodiment is to prepare a two-dimensional derivative plot with BDj removed, either creating the two-dimensional derivative plot with at least BDj removed by clearing BDj or the two-dimensional derivative plot of both BDi and BDj from the two-dimensional derivative plot of the said analyzed object or obtaining the spectral profile with at least BDj removed by clearing BDj or the profile of both BDi and BDj from a spectral profile of the said analyzed object.
Then, the preferred embodiment is to estimate the component band BDk (k is a positive integer where at least k≠j) by estimating band parameter values on BDk other than BDj among the component bands contained in the spectral profile of the analyzed object based on the said characteristic information by obtaining the specific characteristic information based on the said two-dimensional derivative plot with BDi removed.
Thus,
Bruce David V.
Merchant & Gould P.C.
Thomas Courtney
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