7 results about "Spline wavelet" patented technology

The invention discloses a method for analyzing time-frequency characteristics of collision vibration by using a segmented B-spline wavelet collocation method, which comprises the following steps of: (1) establishing a dynamic equation for wavelet discretization, discretizing a dynamic control equation of a collision-vibrator system by using a 4-order B-spline wavelet basis function, and establishing a nonlinear algebraic equation set about a wavelet coefficient; (2) carrying out segmented iterative solution on the time domain, dividing the whole time domain into a plurality of sub-time periods which are connected in sequence, and carrying out iterative solution on the nonlinear algebraic equation set in each sub-time period to obtain a global wavelet coefficient; and (3) analyzing the time-frequency characteristics, and directly calculating energy distribution based on the wavelet coefficient to realize time-frequency joint characterization. The invention aims to provide a method which can fuse solution of system response and extraction of time-frequency characteristics in a unified mathematical framework, and realizes high-precision time-frequency joint characterization by directly solving wavelet coefficients, thereby overcoming inherent defects of an existing two-step method.

The application relates to the field of communication and specifically provides a Fresnel reflection optical fiber diagnosis method and system, which comprises the following steps: collecting a Fresnel reflection signal of a to-be-detected optical fiber to obtain a one-dimensional original time domain signal sequence; adopting a multi-scale decomposition algorithm, taking an asymmetric fractional B-spline wavelet low-pass filter as a convolution kernel to carry out smooth filtering and two-division down-sampling processing on the signal; combining up-sampling and filter difference operation to solve detail components layer by layer until a preset decomposition layer number is reached; calculating a normalized interlayer difference kurtosis to construct a noise suppression factor and weighting denoising of the first scale detail component; up-sampling each scale detail component after denoising to the original signal length, and generating a multi-dimensional feature vector by aggregating components at each time point; calculating the L2 norm square of the time gradient of the feature vector to obtain corresponding fault characteristic values and synthesize a one-dimensional fault feature map; setting a judgment threshold value, positioning the Fresnel reflection position, identifying faults, and realizing optical fiber fault detection and positioning.

The invention discloses a piecewise B-spline wavelet periodic response calculation method for a collision vibration system, which comprises the following steps: (1) establishing a dynamic equation for wavelet discretization, discretizing a dynamic control equation of a collision-vibration system by using a 4-order B-spline wavelet basis function, and establishing a nonlinear algebraic equation set about a wavelet coefficient; (2) carrying out segmented iterative solution on the time domain, dividing the whole time domain into a plurality of sub-time periods which are connected in sequence, and carrying out iterative solution on the nonlinear algebraic equation set in each sub-time period to obtain a global wavelet coefficient; and (3) establishing periodic response reconstruction and analysis, reconstructing displacement, speed and acceleration response of the system based on the wavelet coefficient, and judging periodic response characteristics through judgment conditions. The invention aims to provide a method for calculating the periodic response of a collision-vibration system directly, accurately and efficiently based on a segmented 4-order B-spline wavelet technology.

The application relates to the technical field of power fault identification, and discloses a traveling wave fault positioning method and system. The method is used for positioning a traveling wave fault by screening two traveling wave collecting devices with opposite traveling wave directions and the closest distance, constructing a cubic B-spline wavelet as a wavelet base, performing wavelet decomposition on the traveling wave signals of the screened traveling wave collecting devices, obtaining the highest frequency harmonic component, simulating the harmonic component, determining the fault section in the direction of the first mutation point of the harmonic spectrum obtained through simulation at scale 1, obtaining the wavelet coefficient modulus maximum point at scale 4 of the harmonic spectrum and the corresponding modulus maximum value, calculating the fault time according to the modulus maximum value and the sampling frequency, and calculating the specific position of the fault point in the fault section by using the fault time, so that the fault positioning accuracy is improved.

The application discloses a wing parachute system trajectory planning method, device and equipment based on interval spline wavelet, and the method comprises the steps of establishing a wing parachute dynamics model, constructing an interval spline wavelet base function, defining a wing parachute system trajectory planning process as an optimal control problem, that is, finding control variables and state variables, a fixed initial time and a free end time, minimizing a performance index, and determining constraint conditions, discretizing a time interval into multiple layers of collocation points, expanding state variables and control variables on the collocation points, and converting the constraint conditions into wavelet coefficient form, converting the optimal control problem into a nonlinear programming problem, and solving the nonlinear programming problem to obtain a wing parachute system trajectory planning result. The application is applied to the field of aircraft trajectory optimization, converts the wing parachute system trajectory planning process from an original optimal control problem into a nonlinear programming problem, significantly reduces the calculation dimension, and can strictly meet the end point constraint and adaptively capture trajectory mutation.

The invention discloses an industrial image denoising method and system based on cardinal number type polishing spline wavelets, and relates to the technical field of image processing. The method comprises the steps that a cubic cardinal number type polishing spline function serves as a scaling function, a cardinal number type polishing spline wavelet function with an explicit analytical expression is constructed, a dual-scale equation is established, and coefficients are derived. And carrying out frequency domain processing on the coefficient, and obtaining a reconstructed filter impulse response coefficient according to a complete reconstruction condition, namely, a dual wavelet dual-scale coefficient. A target industrial image is used as initial data, layer wavelet decomposition and nonlinear adaptive threshold processing are carried out through a reconstruction filter and a Mallat dual-channel filter bank to obtain approximation and detail information, then the image is reconstructed through Mallat inverse transformation, and denoising and detail protection are achieved.

The application provides an ultrasonic guided wave dispersion curve calculation method, and belongs to the technical field of ultrasonic measurement. With the increase of the thickness of a to-be-measured plate structure and the increase of the complexity of the structure, if a traditional finite element analysis method is used when a finite element model of the to-be-measured plate structure is constructed, a high-order polynomial interpolation function needs to be used, and a large number of units need to be divided, so that the number of finite element grids increases, and the calculation efficiency is reduced. In the application, the shape function of an interval B-spline small element is used as an interpolation function for solving, the calculation accuracy can be ensured, a large number of units do not need to be divided, the number of finite element grids is reduced, and the calculation efficiency can be improved.