87 results about "Time frequency decomposition" patented technology

A reservoir imaging technique based on full-frequency-band seismic information mining is an oil seismic exploration data processing and interpreting technique, and utilizes the time-frequency decomposition method-the third type generalized S conversion which can accurately describe the local hierarchical structure of seismic signals. Firstly, an original three-dimensional seismic data volume is mapped into a four-dimensional full-frequency-band time-frequency energy data volume, a time-frequency amplitude data volume and a time-frequency phase data volume which all contain time, space and frequency domain; a vertical seismic profile, a time slice, a horizon slice and a stratum slice are extracted from two data volumes by utilizing the geological horizon information and the drilling and logging information; and meanwhile, on the basis of the above data volumes, a full-frequency-band energy difference slice and a reservoir thickness relative to time detection slice which are based on full-frequency-band information are further generated. The technique provided by the invention not only utilizes the information in a passband during conventional seismic data processing but also explores low-frequency and high-frequency information outside the passband, and is used for directly indicating the oil-gas reservoirs and analyzing imperceptible changes of the thickness, the space distribution and the internal structure of reservoirs, thereby improving not only the utilization ratio of the information in the seismic exploration data but also the reliability of seismic data interpretation.

A method of determining sleep stages from signals of electrical activity recorded of a chest of a sleeping subject, the signals being measured over a plurality of epochs. The method comprising: (a) extracting a series of cardiac R-R intervals from the signals and obtaining a time-frequency decomposition from the series of cardiac R-R intervals; (b) using the time-frequency decomposition to determine at least one Slow-Wave-Sleep (SWS) period and at least one Non-SWS (NSWS) period; (c) from the at least one NSWS period, determining at least one sleep-onset (SO) period and a plurality of non-sleep periods; (d) extracting a plurality of electromyogram (EMG) parameters from a portion of the signals, the portion corresponds to a NSWS period other than the at least one SO period and other than the plurality of non-sleep period; (e) using the plurality of EMG parameters to determine at least one REM period thereby also to obtain also at least one light-sleep (LS) period defined as a NSWS period other than the SO periods, other than the non-sleep periods and other than the REM periods; thereby determining the sleep stages of the sleeping subject.

The invention discloses a seismic signal time-frequency decomposition method based on short-time fractional Fourier transform. A Gaussian window function is selected; high frequency resolution is obtained by adjusting the window width in a self-adapting way; through the characteristic of fractional kernel function angle rotation, the best energy accumulation of the seismic signal is obtained at the optimal rotation angle and the cross term is eliminated; the higher frequency resolution and more accurate frequency location are more conductive to recognizing specific geologic structure, so that the method solves the defects of the existing seismic signal time-frequency decomposition method. The method has the positive effects of overcoming the defects of traditional algorithm such as short-time Fourier and Wigner-Ville distribution and the like and having great significance on seismic signal spectral analysis.

The invention discloses a seismic attenuation qualitative estimation method based on self-adaptive optimal kernel time frequency distribution. The method comprises the following steps of 1) collecting original seismic data; 2) picking a position of a seismic data target layer; 3) determining a high frequency fH and a low frequency fL; 4) calculating self-adaptive optimal kernel time frequency distribution for each signal in the superimposed seismic data body to obtain a high-frequency component and a low-frequency component; 5) determining a correction factor; and 6) estimating the seismic attenuation. According to the method, the self-adaptive optimal kernel time frequency distribution is firstly used for carrying out the time frequency decomposition of the seismic data to obtain the high-frequency component and the low-frequency component of the seismic data, and then the seismic attenuation is qualitatively estimated by utilizing the difference of the low-frequency component and the high-frequency component. Compared with the traditional seismic attenuation qualitative estimation method based on the time frequency distribution, the method has high time-frequency resolution ratio, and the seismic attenuation can be more precisely reflected; and in addition, the technical scheme is easy to realize, and the operability is strong.

The invention discloses a time frequency decomposition and reconstruction method of generalized S transform signals for synchronous extrusion. Firstly, the four parameter generalized S transform is conducted on a signal, the variation trend of a basic wavelet function is adjusted by the adjustment of the basic wavelet amplitude, energy attenuation rate, energy delay time and basic wavelet video rate; secondly, the modulus of the result of the four parameter generalized S transform is obtained, and the energy of each time-frequency point is obtained, thus the time-frequency spectrum is obtained; thirdly, the instantaneous frequency is obtained by the four parameter generalized S transform of the signal; fourthly, the frequency set after the generalized S transform is set as the central frequency set, each time frequency point corresponding to the instantaneous frequency close to the interval of the central frequency is extruded to the central frequency point, and the generalized S transform of synchronous extrusion is obtained; finally, the inverse transformation formula of generalized S transform for synchronous extrusion is deduced. The generalized S transform of synchronous extrusion has the advantages of synchronous extrusion transform and generalized S transform, and is a time-frequency decomposition and reconstruction method for high precision signals.

The invention discloses an improved electric vehicle charging non-linear load harmonic wave electric energy metering method. On the basis of the Fourier transform algorithm, the method is performed as follows: using a time-scale analysis method to construct a data analysis algorithm which is consistent with the charging characteristic distribution of an electric vehicle; checking the localized characteristics of a non-stable signal; adjusting the widths of the time window and the frequency window to realize the variable time-frequency resolution; optimizing the electric vehicle non-linear load harmonic wave electric energy metering method; identifying and separating the steady-state harmonic waves and non-steady-state harmonic waves; conducting time-frequency decomposition, stratification and reconstruction to the signal; and achieving the purpose of accurate metering in the entire process. The method of the invention can separate the steady-state and non-steady-state harmonic waves generated by the nonlinear load during the charging operation of the electric vehicle, and performs the multi-scale refinement analysis of the electric power harmonic signal by the telescopic and translational operation of the time scale, which solves the insufficiency problem in Fourier transform in electric vehicle charging non-linear load harmonic wave electric energy metering, therefore, raising the accuracy of electric vehicle charging energy metering.

The invention discloses a realization method of frequency domain amplitude spectrum kurtosis diagram. The realization method comprises the following steps: firstly performing frequency slice wavelet transform on a signal to obtain a time frequency decomposition matrix, on this basis, performing signal reconstruction according to each sub frequency band with given scale, and solving an mean amplitude of a reconstructed signal, performing Fourier transform to obtain a square spectrum of the constructed signal, solving the spectrum kurtosis for an amplitude sequence of the square spectrum, and arranging the spectrum kurtosis diagram values according to scale-frequency band so as to obtain a spectrum kurtosis diagram. The size of the spectrum kurtosis is represented by using the color depth inthe spectrum kurtosis diagram, the larger the spectrum kurtosis value is, the deeper the color of the corresponding spectrum plane region is; in the application, the frequency band corresponding to the plane region with the deepest color is selected to reconstruct so as to obtain the time frequency feature signal for further analysis. The realization method disclosed by the invention can be usedfor signal analysis and fault feature extraction of the mechanical equipment and the electric system; and especially for the signal with the frequency-modulation and amplitude-modulation feature, theoptimal modulation frequency band of the frequency-modulation and amplitude-modulation component can be displayed in the diagram.

The invention relates to a two-channel speech enhancement system and method, and belongs to the field of speech processing. The two-channel speech enhancement system comprises a speech input end used for collecting speech information and a speech processor. The speech input end is used for collecting near-end target speech information through two channels, and the collected speech information is subjected to speech enhancement processing and then is transmitted to a communication equipment terminal used for receiving language signals, wherein speech enhancement processing includes the steps of time-frequency decomposition, power spectrum smoothness, feature extraction, attenuation coefficient generation, signal reestablishment and the like. According to the two-channel speech enhancement system and method, on the basis of the principle of computational auditory sense analysis, two paths of telephone transmitters are used as input, in a near-end speaking mode, good restraining and removing effects are achieved for strong background noise, the overall noise reduction effect is greatly superior to that of a current military 'near-speaking pressure difference' telephone transmitter, the signal to noise ratio can be effectively increased during voice communication, good speech quality is guaranteed, and the problems that the noise reduction effect of the military telephone transmitter in the prior art is poor and the speech quality is influenced are solved.

The invention provides a fluid identification method and a fluid identification device, wherein the fluid identification method comprises the steps of acquiring a prestack angle gather data volume of a researched area; performing angled stacking on the prestack angle gather data volume seismic data for obtaining an angled-stacked data volume; performing prestack AVO inversion on the angled-stacked data volume for obtaining a longitudinal-wave impedance body and a density body; performing time-frequency decomposition processing on the longitudinal-wave impedance member for obtaining a dividing frequency impedance body; performing inversion operation on the dividing frequency impedance body according to the density body, thereby obtaining a reservoir seismic frequency dispersion attribute on the researched area; and performing fluid identification according to the reservoir seismic frequency dispersion attribute. The fluid identification method and the fluid identification device settle a technical problem of incapability of accurately and effectively performing fluid identification in prior art and realizes a purpose of accurately identifying fluid.