Noise level estimation method, measurement data processing device, and program for processing measurement data

A measurement data processing device used for estimating a magnitude of a noise component, the device comprising:

• a processor configured to:
• a) obtain measurement data including a peak component and the noise component, by measuring an intensity of a signal that changes with respect to a predetermined physical quantity, the measurement data being obtained through chromatography, spectrophotometry, or mass spectrometry;
• b) perform a time-frequency analysis on the measurement data to obtain, for each of a plurality of predetermined frequencies, waveform data representing a change in an intensity of a frequency component in the signal with respect to the predetermined physical quantity;
• c) divide the waveform data of each of the plurality of predetermined frequencies into a plurality of segments so that each segment includes successive positive values or successive negative values in a direction of a change in the physical quantity, or so that each segment is between a local maximum and a local minimum neighboring each other in the direction of the change in the physical quantity;
• d) determine a magnitude of each of the plurality of segments in the waveform data of each of the plurality of predetermined frequencies;
• e) create, for the waveform data of each of the plurality of predetermined frequencies, a selected segment group by excluding a segment whose magnitude exceeds a predetermined reference value from the plurality of segments in the waveform data;
• and
• f) determine a noise level of each of the plurality of predetermined frequencies by calculating an average or a median of the magnitudes of the segments included in the selected segment group.

A non-transitory computer readable medium recording a program for estimating a magnitude of a noise component, the program causing a computer to:

• a) obtain measurement data including a peak component and the noise component, by measuring an intensity of a signal that changes with respect to a predetermined physical quantity, the measurement data being obtained through chromatography, spectrophotometry, or mass spectrometry;
• b) perform a time-frequency analysis on the measurement data to obtain, for each of a plurality of predetermined frequencies, waveform data representing a change in an intensity of a frequency component in the aforementioned signal with respect to the predetermined physical quantity;
• c) divide the waveform data of each of the plurality of predetermined frequencies into a plurality of segments so that each segment includes successive positive values or successive negative values in a direction of a change in the physical quantity, or so that each segment is between a local maximum and a local minimum neighboring each other in the direction of the change in the physical quantity;
• d) determine a magnitude of each of the plurality of segments in the waveform data of each of the plurality of predetermined frequencies;
• e) create, for the waveform data of each of the plurality of predetermined frequencies, a selected segment group by excluding a segment whose magnitude exceeds a predetermined reference value from the plurality of segments in the waveform data;
• and
• f) determine a noise level of each of the plurality of predetermined frequencies by calculating an average or a median of the magnitudes of the segments included in the selected segment group.