Apparatus and method for monitoring stability of spectrum

A method for monitoring a spectrum stability, the method comprising:

• measuring, by a spectroscope, spectra of a sample, the spectra comprising an initial spectrum which is a first measured spectrum from the sample and a plurality of subsequent spectra which are spectra measured after the initial spectrum that are measured from the sample;
• determining a similarity change index of the spectra in a time domain based on differences between the initial spectrum of the sample and each of the plurality of subsequent spectra of the sample, in real time while measuring the spectra;
• controlling the spectroscope to measure the spectra of the sample based on the similarity change index;
• comparing the similarity change index with a preset threshold value to obtain a comparison result;
• and
• determining the spectrum stability based on the comparison result,
• wherein the plurality of subsequent spectra comprises a first subsequent spectrum and a second subsequent spectrum, and
• wherein the determining of the similarity change index comprises performing a time domain analysis on the spectra of the sample by calculating a first degree of similarity between the initial spectrum and the first subsequent spectrum in the time domain, calculating a second degree of similarity between the initial spectrum and the second subsequent spectrum in the time domain, calculating a change between the first degree of similarity and the second degree of similarity in the time domain, and calculating the similarity change index in the time domain by converting the calculated change into a score,
• wherein the determining of the similarity change index comprises determining the similarity change index further based on an average of at least two degrees of similarity between any two spectra from among a predetermined number of consecutive spectra.

An apparatus for monitoring a spectrum stability, comprising:

• a communicator configured to receive, from a spectrum measurement apparatus, spectra of a sample measured in real time, the spectra comprising an initial spectrum which is a first measured spectrum and a plurality of subsequent spectra which are spectra measured after the initial spectrum;
• and
• a processor configured to:
• determine a similarity change index of the spectra in a time domain based on differences between the initial spectrum of the sample and each of the plurality of subsequent spectra of the sample, in real time while measuring the spectra;
• and
• generate a control signal that causes the spectrum measurement apparatus to measure the spectra of the sample based on the similarity change index by determining the similarity change index,
• wherein the plurality of subsequent spectra comprises a first subsequent spectrum and a second subsequent spectrum, and
• the processor is further configured to perform a time domain analysis on the spectra of the sample, calculate a first degree of similarity between the initial spectrum and the first subsequent spectrum in the time domain, to calculate a second degree of similarity between the initial spectrum and the second subsequent spectrum in the time domain, to calculate a change between the first degree of similarity and the second degree of similarity in the time domain, and to calculate the similarity change index in the time domain by converting the calculated change into a score,
• wherein the processor is further configured to calculate at least two degrees of similarity between any two spectra from among a predetermined number of consecutive spectra, to compute an average of the calculated at least two degrees of similarity, and to calculate the similarity change index by converting the computed average into a score, and
• wherein the processor is configured to compare the similarity change index with a preset threshold value to obtain a comparison result, and determine the spectrum stability based on the comparison result.