The invention discloses an optimum design method for an M channel oversampling image filter set based on convex optimization. By means of a two-step method, target optimization is performed, the spectral selectivity and perfect reconstruction conditions of the image filter set are comprehensively considered, and therefore it is ensured that the whole performance of the image filter set is improved under the small reconstruction error condition. The simple and effective solution is provided for lowering the reconstruction error of the image filter set and achieving signal restoration and reconstruction.

Optimum design method for M channel oversampling image filter set based on convex optimization

The invention discloses a wavelet filter for extracting an effective quench signal of a high temperature superconducting magnet. The wavelet filter comprises an AD conversion module, a wavelet analysis module, a control module and a DA conversion module, wherein the wavelet analysis module is used to filter a quench signal of the high temperature superconducting magnet; the control module is usedto adjust a filter coefficient of the device; and through the control module, output signals can be controlled to achieve free adjustment within a total of 11 levels from 0%, 10%,...... to 100%. According to the wavelet filter disclosed by the invention, the online filtering of the quench signal can be realized. Results show that by adopting the wavelet filter disclosed by the invention, voltage fluctuations coupled to the quench signal caused by current fluctuations can be effectively filtered; the method can be applied to a quench protection system of the superconducting magnet, and protection misoperations caused by the voltage fluctuations can be effectively prevented; and the wavelet filter has great significance for the long-time stable operation of superconducting equipment.

Wavelet filter for extracting effective quench signal of high temperature superconducting magnet

The invention belongs to the seismic exploration technical field and relates to a four-channel redundancy filter bank-based slot weak signal extraction method. The method includes the following steps that: a decomposition filter bank forms a decomposition convolution matrix; slot wave signals are decomposed into different frequency subbands through the decomposition convolution matrix; soft threshold denoising operators are inserted into each frequency subband, so that soft threshold denoising can be performed on the frequency subbands; and reconstruction filters form a reconstruction convolution matrix, and denoising is performed on the reconstruction convolution matrix, and then, new signals can be obtained through the synthesis of the reconstruction convolution matrix. The method has the advantages of simple process, scientific and reliable principles, excellent denoising effect, high signal resolution and strong reconfiguration capability.

Four-channel redundancy filter bank-based slot weak signal extraction method

The invention discloses a ground penetrating radar signal quantitative analysis method and system. The method comprises steps: ground penetrating radar signals are acquired; the ground penetrating radar signals are filtered to determine a detected target in a radar image; the detected target is extracted to obtain multiple single channel signals containing detected target reflected wave information; according to the used ground penetrating radar antenna pulse function type, a corresponding quantitative analysis-used optimal wavelet basis is selected or constructed; the optimal wavelet basis isadopted to process each single channel signal to obtain multiple detail coefficient component time-modulus curves; a wavelet singularity analysis method is adopted to determine multiple detected target reflected waves in each detail coefficient component time-modulus curve; a wavelet modulus maximum method and the multiple detected target reflected waves are used to determine the coordinates of alocal modulus maximum point; and a two-way travel time formula and the coordinates of the local modulus maximum point are used to calculate the distance between different detected target reflected waves. By adopting the method or the system disclosed in the invention, accurate quantitative analysis on the ground penetrating radar signals can be realized.

Ground penetrating radar signal quantitative analysis method and system

The invention relates to application of a Mallat algorithm in heart sound signal noise reduction based on a genetic algorithm optimization threshold. The method comprises the steps that on the basis of the genetic algorithm optimization threshold, the Mallat algorithm with the optimized threshold is used for performing denoising on high-frequency section heart sound signals and low-frequency section heart sound signals respectively; finally, on the basis of the signal to noise ratio, the effect of denoising is reflected. The method is high in processing speed, more detailed signals are reserved, usable signals and noise can be better distinguished, no new noise is introduced, and the denoising effect is good.

Application of Mallat algorithm in heart sound signal noise reduction based on genetic algorithm optimization threshold

The invention discloses a method for constructing a biorthogonal wavelet filter bank. The method includes the following steps: determining the length N of a decomposition low-pass filter h(n) and the length M of a reconstruction low-pass filter (please see the specifications) according to the requirements of wavelet functions to be constructed, wherein the N and the M are even numbers; determining the orders of vanishing moments of dual wavelet generating functions (please see the specifications) to be constructed; calculating the biorthogonal complete reconstruction filter bank according to a formula set to obtain a set of coefficients of the biorthogonal complete reconstruction filter bank; substituting the results into a dual-scale equation to construct a set of biorthogonal wavelet bases (please see the specifications), decomposing a decomposition high-pass filter corresponding to the wavelet function (please see the specifications), and reconstructing a reconstruction high-pass filter corresponding to the wavelet function (please see the specifications). Compared with common db-series wavelet filter banks and common bior-series wavelet filter banks, heart sound signals are processed through the biorthogonal wavelet filter bank constructed with the method, and the better noise reduction effect, the accurate heart sound classified information and the smaller reconstruction error rate can be obtained.

Zhang Zheng

Papers

Method for constructing biorthogonal wavelet filter bank