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US 8,527,227 B2Granted
Method and device for measuring electromagnetic wave
AssigneeCanon Kabushiki Kaisha
InventorMichinori Shioda
Life of this patent
Estimating the term…
Abstract
A waveform acquiring unit acquires a time waveform of an electromagnetic wave. The time waveform is decomposed into wavelet expansion coefficients by wavelet transform. Influence levels of the respective wavelet expansion coefficients to a spectrum are calculated. The wavelet expansion coefficients are weighted based on at least the influence levels of the wavelet expansion coefficients to the spectrum. The weighted wavelet expansion coefficients are converted into time waveforms by inverse wavelet transform. Thus, the time waveforms that holds spectrum information needed for spectroscopic analysis and has a reduced noise is provided.
Claims14
An electromagnetic wave measurement method for measuring an electromagnetic wave, the method comprising:
- acquiring a time waveform of the electromagnetic wave;
- decomposing the time waveform of the electromagnetic wave into wavelet expansion coefficients by wavelet transform;
- calculating influence levels of the respective wavelet expansion coefficients to a spectrum in a predetermined measurement range;
- weighting the wavelet expansion coefficients, using a processor, based on at least the influence levels of the respective wavelet expansion coefficients to the spectrum;
- and
- converting the weighted wavelet expansion coefficients into time waveforms by inverse wavelet transform,
- wherein the calculation for the influence levels of the respective wavelet expansion coefficients to the spectrum includes:
- extracting a single value from the decomposed wavelet expansion coefficients,
- reconstructing the single value into a time waveform by the inverse wavelet transform,
- converting the reconstructed time waveform by Fourier transform,
- calculating a value as one of the influence levels by adding a signal intensity of at least a single frequency;
- the signal intensity being derived from the Fourier transform, and
- repeating the calculation for the respective wavelet expansion coefficients.
10 more elements
An electromagnetic wave measurement device that measures an electromagnetic wave, the device comprising:
- a wave acquiring unit configured to acquire a time waveform of the electromagnetic wave;
- a decomposing unit configured to decompose the time waveform of the electromagnetic wave into wavelet expansion coefficients by wavelet transform;
- a calculating unit configured to calculate influence levels of the respective wavelet expansion coefficients to a spectrum in a predetermined measurement range;
- a weighting unit configured to weight the wavelet expansion coefficients based on at least the influence levels of the respective wavelet expansion coefficients to the spectrum;
- and
- a converting unit configured to convert the weighted wavelet expansion coefficients into time waveforms by inverse wavelet transform,
- wherein the calculating unit
- extracts a single value from the decomposed wavelet expansion coefficients,
- reconstructs the single value into a time waveform by the inverse wavelet transform,
- converts the reconstructed time waveform by Fourier transform,
- calculates a value as one of the influence levels by adding a signal intensity of at least a single frequency;
- the signal intensity being derived from the Fourier transform, and
- repeats the calculation for the respective wavelet expansion coefficients.
10 more elements
An electromagnetic wave measurement method for measuring an electromagnetic wave, the method comprising:
- acquiring a time waveform of the electromagnetic wave;
- decomposing the time waveform of the electromagnetic wave into wavelet expansion coefficients by wavelet transform;
- calculating influence levels of the respective wavelet expansion coefficients to a spectrum in a predetermined measurement range;
- weighting the wavelet expansion coefficients, using a processor, based on at least the influence levels of the respective wavelet expansion coefficients to the spectrum;
- and
- converting the weighted wavelet expansion coefficients into time waveforms by inverse wavelet transform,
- wherein the calculation for the influence levels of the respective wavelet expansion coefficients to the spectrum includes:
- extracting a single value of the wavelet expansion coefficients which are decomposed in advance,
- regularizing the value,
- reconstructing the regularized value into a time waveform by the inverse wavelet transform,
- converting the reconstructed time waveform by Fourier transform,
- calculating a value as one of the influence levels by adding a signal intensity of at least a single frequency;
- the signal intensity being derived from the Fourier transform, and
- repeating the calculation for the respective wavelet expansion coefficients.
11 more elements
An electromagnetic wave measurement device that measures an electromagnetic wave, the device comprising:
- a wave acquiring unit configured to acquire a time waveform of the electromagnetic wave;
- a decomposing unit configured to decompose the time waveform of the electromagnetic wave into wavelet expansion coefficients by wavelet transform;
- a calculating unit configured to calculate influence levels of the respective wavelet expansion coefficients to a spectrum in a predetermined measurement range;
- a weighting unit configured to weight the wavelet expansion coefficients based on at least the influence levels of the respective wavelet expansion coefficients to the spectrum;
- and
- a converting unit configured to convert the weighted wavelet expansion coefficients into time waveforms by inverse wavelet transform,
- wherein the calculating unit
- extracts a single value of the wavelet expansion coefficients which are decomposed in advance,
- regularizes the value,
- reconstructs the regularized value into a time waveform by the inverse wavelet transform,
- converts the reconstructed time waveform by Fourier transform,
- calculates a value as one of the influence levels by adding a signal intensity of at least a single frequency;
- the signal intensity being derived from the Fourier transform, and
- repeats the calculation for the respective wavelet expansion coefficients.
11 more elements
Dependencies are inferred from the claim text.