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487 results about "Wave transformation" patented technology

Bearing fault diagnosis method and system device based on improved empirical wavelet transform

InactiveCN108375472AImprove the shortcomings of unreasonable segmentationAvoid mode aliasingMachine bearings testingCharacter and pattern recognitionCorrelation coefficientFrequency spectrum
The invention provides a bearing fault diagnosis method and system device based on improved empirical wavelet transform. The method comprises: step one, collecting different fault bearing signals as analysis signals and converting a time domain waveform into a frequency domain waveform; step two, drawing an upper envelope of a frequency spectrum and transforming a frequency peak with a tight support into a flat top; step three, screening flat tops in the frequency domain based on criteria, removing meaningless flat tops, and keeping a main frequency; step four, using a minimum value between adjacent flat tops as the boundary of spectrum segmentation; step five, establishing wavelet filters respectively for segmented frequency spectrums and decomposing the signals into N mode components; step six, calculating similarity values between mode components and the original signals by using a cross-correlation coefficient and selecting a component with the highest similarity value; and step seven, taking a fault sample, calculating an IMF component with the largest correlation coefficient of the sample, calculating a multi-scale entropy of the IMF component, and drawing the multi-scale entropy curve of the sample to realize fault classification.
Owner:WUHAN UNIV OF SCI & TECH

Multi-focusing image fusion method utilizing core Fisher classification and redundant wavelet transformation

The invention discloses a multi-focusing image fusion method utilizing core Fisher classification and redundant wavelet transformation. The method comprises the following steps: firstly, carrying out image block segmentation on source images and calculating definition characteristics of each image block; secondly, taking part of areas of the source images as a training sample and obtaining various parameters of a core Fisher classifier after training; thirdly, utilizing the known core Fisher classifier to obtain preliminary fusion images; and finally, utilizing redundant wavelet transformation and space correlation coefficients to carry out fusion processing on the image blocks positioned at the junction of the clear and fuzzy areas of the source images to obtain final fusion images. The invention has better image fusion performance, does not have obvious blocking artifacts and artifacts in fusion results, obtains better compromise between the effective enhancement of the image fusion quality and the reduction of the calculation quantity and can be used in the subsequent image processing and display. When wavelet decomposition layers with less number are adopted, the invention is more suitable for an occasion with higher real-time requirement.
Owner:CHONGQING SURVEY INST

Partial discharge detection identification method based on ultrasound and ultraviolet information fusion and system thereof

The invention discloses a partial discharge detection identification method based on ultrasound and ultraviolet information fusion. The method comprises the following steps: S1. uniformly setting sensing detection circuits in surrounding space of a detected object; S2. real-timely collecting an ultrasonic signal and an ultraviolet signal generated when partial discharge is generated in a detected area, after the signals are processed, sending to a digital signal processing circuit; S3. carrying out digital filtering processing; S4. extracting dual density wavelet transform wavelet coefficient Shannon entropy x from the ultrasonic signal generated in S3, extracting wavelet packet wavelet coefficient Shannon entropy y, and sending a characteristic vector x and a characteristic vector y to a detection system host via a communication module; S5. carrying out characteristic fusion by the detection system host so as to obtain the characteristic vector z after the fusion; S6. classifying the vector z obtained in S5 after the fusion by using support vector machine classification trees. By using the method of the invention, application of a detection identification technology based on the ultrasound and ultraviolet information fusion can be promoted; high accuracy, reliability and instantaneity of the partial discharge detection can be ensured.
Owner:CHONGQING UNIV

Wavelet transform and joint sparse representation-based infrared and visible light image fusion method

The invention provides a wavelet transform and joint sparse representation-based infrared and invisible light image fusion method, and relates to the field of image fusion. The method comprises the following steps of: firstly, carrying out DWT transform on a source image, decomposing the source image into a low-frequency sub-band matrix coefficient and a high-frequency sub-band coefficient, decomposing the low-frequency sub-band coefficient into a matrix by using a sliding window strategy and learning a dictionary in allusion to the decomposed low-frequency sub-band matrix; secondly, respectively fusing the low-frequency sub-band coefficient and the high-frequency sub-band coefficient; and finally reconstructing a fused image through DWT inverse transform. According to the method, effective sparse representation can be carried out on outstanding detail features of source images, and multi-scale fusion can be carried out on detail information of the images, so that target information of infrared images and background information such as details, profiles and the like of invisible light images are well retained, the target identification ability is improved, and benefit is brought to subsequent processing systems to extract and use the information; and compared with the traditional wavelet transform-based fusion method and the existing joint sparse representation-based fusion method, method provided by the invention has advantages.
Owner:NORTHWESTERN POLYTECHNICAL UNIV

Synthetic aperture radar image denoising method based on non-down sampling profile wave

ActiveCN101482617AAvoid jitter distortionAdaptive denoisingImage enhancementRadio wave reradiation/reflectionSynthetic aperture radarRadar
The invention discloses a denoising method of synthetic aperture radar image based on a non-lower sampling configuration wave, which is mainly to solve the problem that the image detail is difficult to keep effectively by the existing method, the new method comprises: (1) inputting a SAR image X and performing the L layer non-lower sampling configuration wave transformation; (2) calculating speckle noise variance delta C#-[B] of subband in each high-frequency direction of different dimensions; (3) distinguishing the high-frequency direction subband coefficients into the signal or the noise transformation coefficients by the local average value mean[C1, i(a, b)] high-frequency direction suband coefficient C1 and the i (a, b); (4) reserving the signal part in the judged high-frequency direction subband coefficient C1 and i (a, b) to obtain the denoised high-frequency direction subband coefficient C1 and i (a, b); (5) performing the non-lower sampling configuration wave inverse transformation for the low-frequency subband amd the denoised high-frequency direction subband coefficient C1 and I (a, b) to obtain the denoised SAR image X . The invention can effectively eliminate the coherent speckle noise, meanwhile can effectively keep the image detail, the denoised image has no shake and distortion and can be used for the preprocessing stage of the synthetic aperture radar image.
Owner:XIDIAN UNIV

Modal parameter identification method based on response signal time-frequency joint distribution characteristics

InactiveCN103217213AImproved method of scale selectionFind the scale preciselySubsonic/sonic/ultrasonic wave measurementEngineeringDamping ratio
The invention relates to a modal parameter identification method based on response signal time-frequency joint distribution characteristics. According to the modal parameter identification method based on the response signal time-frequency joint distribution characteristics, signal analysis and structural modal parameter identification are carried out directly through a structural vibration response. The modal parameter identification method based on the response signal time-frequency joint distribution characteristics comprises the steps of firstly carrying out complex wavelet continuous transformation on a structural response signal, obtaining energy distribution characteristics of various wavelet transformation domains (a real domain, a virtual domain, a modal domain and a phase domain), obtaining a time average wavelet energy spectrum through a wavelet transformation coefficient, therefore carrying out quantification on selection of model orders and the scale corresponding to each order modality, on the basis, obtaining the optimum scale required by parameter identification, achieving pre-identification of modal frequency through the corresponding relation of the scale and the frequency, finally extracting a wavelet transformation coefficient slice at the specific scale, carrying out linear fitting through an amplitude value and a phase component, and achieving structural identification of inherent frequency and a damping ratio. As simulation and experiment results show, even if an external incentive function is not included, accurate identification of structural modal parameters can be achieved through the modal parameter identification method based on the response signal time-frequency joint distribution characteristics.
Owner:BEIJING UNIV OF TECH

Power distribution network fault positioning method based on wavelet transformation and CNN

The invention relates to the power distribution network fault positioning technology field and particularly relates to a power distribution network fault positioning method based on wavelet transformation and the CNN. Wavelet transform multi-scale analysis is utilized to decompose fault current data, in the parallel coordinate system, modulus maxima are calibrated in order, points are connected insequence to form a line graph, and lastly, the line graph is processed to be a grayscale image used as the input of the CNN, the powerful feature extraction capability of the CNN is utilized to extract hidden topological structure features in the data, a machine is enabled to automatically identify the traveling wave head, and the B-type traveling wave ranging method is utilized to realize faultpositioning. The method is advantaged in that shortcomings of not-enough wavelet transform high-scale time resolution, large low-scale noise interference and easy false determination of the travelingwave head are overcome, the parallel coordinate system is utilized to fully combine the characteristics of wavelet transform and the convolutional neural network to achieve high-scale to low-scale automatic search for the traveling wave head, and strong anti-interference ability and high accuracy are achieved.
Owner:GUANGDONG POWER GRID CO LTD +1

Automatic identification for double dimension barcode personal certificate antifakery system

The present invention discloses an counterfeit-proof system of the identification certificate with the two-dimension barcode and the automatic identifying method thereof which obtains the information carried in the two-dimension barcode input by a scanning equipment through the image identifying technique. This system and method includes the manufacture of the counterfeit-proof identification certificate, the process of the photograph of the certificate holder, the formation of the two-dimension barcode and the identification of the real / false of the identification certificate. The photograph of the identification certificate is processed using the compression technique which comprises the small wave transformation, the main element analysis, the self-organic characteristic mapping nerve-cell web, the self-adaptive variable gathering sub-block and Huffman encode. In the identification of the two-dimension barcode, the input of the identification certificate with the barcode, the access of the area where the barcode stays and the process of the barcode area are performed by the scanning equipment to obtain the PDF417 encode according to the national standard, and then the carried information is obtained according to the compression of encode and the encryption of information. The real / false of the certificate is determined by comparing the literal information and the numerical information of the certificate obtained by decoding with the information stored in the data base and the information of the determined real certificate can be stored automatically in the data base according to the userí»s requirement.
Owner:XIAN UNIV OF TECH

Wavelet transform and time search strategy based double-end traveling wave fault location method for hybrid power transmission line

The invention discloses a wavelet transform and time search strategy based double-end traveling wave fault location method for hybrid power transmission line. The method comprises the following stepsof 1) determining an electrical topological structure of the hybrid power transmission line MN; 2) acquiring the motion time of traveling waves on a section line according to the length and motion wave speed of each section line; 3) according to fault traveling wave information acquired by traveling wave distance measuring devices at the two ends of the line, adopting wavelet transform to detect and identify the moment when the fault traveling wave moves to each bus measuring end for the first time so as to obtain a time difference when the traveling wave arrives at the two ends of the bus, and calculating t1 an t2 according to formulas by combining movement time of the fault traveling wave on the whole power transmission line; and 4) starts comparing from the end M of the bus, judging that the fault position is behind the xj1 section when t1>deltat1, and judging that the fault position is on the xd1 section when deltat1<t1<deltat1+deltat2, thus calculating the fault position. The method can be used to identify the initial traveling wave of a fault more accurately, and effectively solve the problem in fault distance measurement of the cable and overhead line hybrid power transmission line of the power system.
Owner:JIANGSU ELECTRIC POWER CO +1

Method for inverting vegetation parameters by remote sensing based on reflection spectrum wavelet transform

InactiveCN101986139AImproving the Accuracy of Spectral Remote Sensing RetrievalWide applicabilityColor/spectral properties measurementsSatellite remote sensingCanopy
The invention relates to a method for inverting vegetation parameters by remote sensing based on reflection spectrum wavelet transform. The method comprises the following steps of: 1) acquiring the vegetation parameters and the original spectrum thereof under different conditions, and performing spectrum transform on the original spectrum; 2) performing continuous wavelet transform on the original spectrum by using different wavelet functions, and generating wavelet coefficients with different frequencies; 3) performing stepwise regression by taking different scales of wavelet coefficients as independent variables and taking the vegetation parameters as dependent variables, selecting spectrum wave bands needed by the inversion of the vegetation parameters, constructing a model of quantitative inversion of the vegetation parameters, and calculating R2 of the model; and 4) comparing modeling R2 of the constructed model according to different wavelet decomposition scales, and determining the model with the maximum modeling R2 as the optimal model. By the method, the hyperspectral remote sensing inversion precision of the vegetation parameters can be obviously improved, and the remote sensing inversion precision of biochemical parameters can be improved preferably. The method has wide parameter applicability, is applicable to leaf or canopy reflection spectrum, and is applicable to satellite remote sensing hyperspectral data.
Owner:ZHEJIANG UNIV

Method for detecting internal and external faults of ultra high voltage direct current transmission lines based on pole wave mathematical morphology spectrum

The invention provides a method for detecting internal and external faults of ultra high voltage direct current transmission lines based on pole wave mathematical pattern spectrum. The method is characterized in that when a direct current (DC) line fault occurs, a starting component is started, according to positive pole line DC voltage U+(k) and DC I+(k) which are collected by a protection installation location, pole wave voltage of a positive pole line is obtained, and the positive pole line pole wave voltage is subjected to wavelet transform, pole wave voltage high frequency characteristic quantity PG+(k) of a high frequency portion of the positive pole line pole wave voltage is extracted. The pole wave voltage high frequency characteristic quantity is calculated by means of mathematical morphology, a mathematical morphology spectrum value of the pole wave voltage high frequency characteristic quantity is obtained, structure element scale needed is selected, and the mathematical morphology spectrum value is subjected to integration operation along abscissa axis structure element scale. Internal and external faults are distinguished according to the integration operation value. The method has the advantages of being sensitive in identifying the internal faults, reliable in identifying the external faults and applicable to the popularization and the usage in direct current transmission line systems.
Owner:KUNMING UNIV OF SCI & TECH

Use of machine learning for classification of magneto cardiograms

The use of machine learning for pattern recognition in magnetocardiography (MCG) that measures magnetic fields emitted by the electrophysiological activity of the heart is disclosed herein. Direct kernel methods are used to separate abnormal MCG heart patterns from normal ones. For unsupervised learning, Direct Kernel based Self-Organizing Maps are introduced. For supervised learning Direct Kernel Partial Least Squares and (Direct) Kernel Ridge Regression are used. These results are then compared with classical Support Vector Machines and Kernel Partial Least Squares. The hyper-parameters for these methods are tuned on a validation subset of the training data before testing. Also investigated is the most effective pre-processing, using local, vertical, horizontal and two-dimensional (global) Mahanalobis scaling, wavelet transforms, and variable selection by filtering. The results, similar for all three methods, were encouraging, exceeding the quality of classification achieved by the trained experts. Thus, a device and associated method for classifying cardiography data is disclosed, comprising applying a kernel transform to sensed data acquired from sensors sensing electromagnetic heart activity, resulting in transformed data, prior to classifying the transformed data using machine learning.
Owner:CARDIOMAG IMAGING

Rolling bearing fault diagnosis method for improving model migration strategy

The invention discloses a rolling bearing fault diagnosis method for improving a model migration strategy, and belongs to the technical field of rolling bearing fault diagnosis. The method is providedfor solving the problem of large distribution difference of data in the same state in a source domain and a target domain, and comprises: obtaining time-frequency spectrums of vibration signals of different types of bearings through wavelet transform, and constructing an image data set; selecting data of a certain model as a source domain, and selecting data of other models as a target domain; training a ResNet-34 deep convolutional network by using the source domain data to obtain a source domain data classification model; adaptively determining a migration knowledge level and knowledge content by using implicit gradient meta-learning to realize improvement of a model migration strategy and avoid a phenomenon that a gradient in a heterogeneous system structure is not easy to converge; introducing the migrated knowledge into a target domain ResNet-152 convolutional neural network data training process, and realizing model migration through parameter transmission; and optimizing network parameters by adopting a stochastic gradient descent algorithm when the source domain network and the target domain network are trained, and establishing fault diagnosis models of different types ofrolling bearings.
Owner:HARBIN UNIV OF SCI & TECH

Radar based respiration and heartbeat signal detection method and system

The invention discloses a radar based respiration and heartbeat signal detection method and system. The method comprises the steps of A, judging whether a target exists based on a transmitting signaland a receiving signal; and B, performing the following processing on a mixed vital sign signal of the target: B1, performing high-pass filtering and FFT on the mixed vital sign signal to obtain firstfrequency spectrum data; B2, if the frequency corresponding to a maximum amplitude value point is within a respiratory frequency range and the maximum amplitude value point exists at a Q frequency doubling position and/or near the Q frequency doubling position of the frequency, taking the frequency as a respiratory dominant frequency; B3, decomposing the mixed vital sign signal of the target based on empirical wavelet transform; and B4, if the maximum value frequency of a third component or a fourth component is within a preset heartbeat frequency range, taking the maximum value frequency asa heartbeat dominant frequency. Based on the empirical wavelet transform, respiration and heartbeat signals are adaptively separated and the frequencies of the respiration and heartbeat signals are accurately extracted, and the respiration and heartbeat frequencies of multiple persons can be simultaneously extracted and separated for a broadband/ultra-wideband radar.
Owner:ARMY MEDICAL UNIV

Blind source extraction-based atrial fibrillation monitoring method

The invention belongs to a monitoring method for an atrial fibrillation disease. The method comprises initialized setting of monitoring standard parameters, data acquisition, baseline drift removal, determination of heart rate, early warning, extraction of AR characteristic signals, extraction of normal electrocardio, normal electrocardio removal with spectral subtraction, nonlinear dimension expansion, separation processing of the signals, spectrum concentration analysis and alarm. The method determines the AR of the normal electrocardio and the AR characteristic signals of abnormal electrocardio of a monitored person based on extraction of atrial fibrillation signals with blind source extracting technology according to the spectrum characteristics when the atrial fibrillation disease attacks by combing the signal processing technology of wavelet transform, nonlinear expansion, spectral subtraction and the like and skillfully using the heart rate parameters and the 'normal' and 'abnormal' electrocardio of a patient. Compared with the traditional monitoring method, the method effectively reduces the consumption of manpower and time for monitoring data analysis, greatly improves the real-time property of atrial fibrillation monitoring and the monitoring accuracy, and is more favorable for clinical application.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA
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