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80 results about "Filtering theory" patented technology

Multi-classifier system-based synthetic aperture radar automatic target recognition method

The invention discloses a synthetic aperture radar automatic target recognition method which belongs to the target recognition field and mainly solves the problem that the space complexity of the existing synthetic aperture radar automatic target recognition technology is higher and single classifier has low recognition rate. The method comprises the following recognition steps: preprocessing, extracting characteristics, training classifiers and identifying target, wherein the step of extracting characteristics is to extract PCA characteristics of the synthetic aperture radar image, elliptic Fourier descriptor and two-dimensional Fourier transform; the step of training classifiers is based on the extracted three characteristics to separately use K-nearest neighbor method, support vector machine and MINACE filter theory to train three classifiers; and the step of identifying target is to input the extracted synthetic aperture radar image to be identified in the trained three classifiers for classification and finally adopting the Dempster-Shafer evidence theory to fuse the recognition results of the three classifiers. The method has the advantages of high recognition rate and low space complexity and can be used in the target tracking of the military or civilian field.
Owner:XIDIAN UNIV

Distributed passive radar target detection method under direct wave-free condition

The invention discloses a distributed passive radar target detection method under a direct wave-free condition, and belongs to the technical field of distributed passive radar target detection. A conventional passive radar target detection method is based on the classical matched filtering theory, and approximately optimal detection properties can be achieved on premise that a direct wave with a relatively high signal-to-noise ratio can be acquired in real time and an emitted signal can be estimated with high quality by using a direct wave signal received by a reference channel. To solve the problem of detecting a target which cannot receive the direct wave signal in practical, the invention discloses the distributed passive radar target detection method under a direct wave-free condition, and a concentrated target detector under the direct wave-free condition is established, so that target detection can be implemented when the signal-to-noise ratio of the direct wave signal is relatively low or the direct wave signal cannot be received in a multiple-input multiple-output geometric structure, and meanwhile the target matching problem which is very hard to solve among different receiving stations of a distributed passive radar is indirectly avoided.
Owner:NAVAL AVIATION UNIV

Parameter estimation and tracking control method based on turntable servo system

ActiveCN107102634ARealize position tracking controlReduce position tracking controlElectric testing/monitoringMathematical modelFiltering theory
The invention discloses a parameter estimation and tracking control method based on a turntable servo system, and belongs to the technical field of parameter identification and electromechanical control. The method comprises analyzing the turntable servo system containing unknown parameters, establishing a mathematical model of the turntable servo system containing unknown parameters according to a mechanism modeling method; updating an adaptive rate by a filtering theory, introducing a performance index function with a forgetting factor, and designing a variable-gain adaptive rate to achieve optimal adaptive parameter estimation by optimizing the performance index function; and achieving position tracking control by using the controller of a sliding-mode control design system using a super-twisting algorithm. The method can achieve the parameter estimation and tracking control of a system and has advantages of (1) reducing a system parameter estimation overshoot and accelerating the convergence of parameter estimation; (2) ensuring that a tracking error converges to zero within finite time; being not required to obtain the derivative information of a sliding-mode variable or not requiring a continuous control law of the sliding mode; eliminating chattering and improving the robustness of the controller.
Owner:BEIJING INSTITUTE OF TECHNOLOGYGY

Attitude heading measurement system and fusion method thereof, and storage medium

The invention discloses an attitude heading measurement system and a fusion method thereof, and a storage medium. The fusion method comprises the following steps of acquiring real attitude angles psi,gamma and theta of a car body by weighting of a three-antenna GNSS (Global Navigation Satellite System) and an accelerometer, wherein psi is a heading angle of the car body, gamma is a roll angle ofthe car body and theta is a pitch angle of the car body; acquiring zero offsets deltabx, deltaby, deltabz of a gyroscope; and performing fusion processing on the attitude angles psi, gamma and theta of the car body acquired by weighting of the three-antenna GNSS and the accelerometer and the zero offsets deltabx, deltaby, deltabz of the gyroscope through a Kalman filtering model to obtain an optimal estimation value of the attitude angles of the car body. According to the attitude heading measurement system and the fusion method thereof, and the storage medium, a weighted observation is performed on an output angle of the gyroscope by using the angles output by the accelerometer and a three-antenna GNSS receiver; the angles are fused on the basis of a Kalman filtering theory; the measurement precision is high; and the high requirement of the modern agricultural machinery navigation on the precision of the attitude angle can be satisfied.
Owner:广州中海达定位技术有限公司

Method for controlling level of digital audio signal

ActiveCN105322904AMeet the distortion rateMeet needsGain controlFiltering theoryDigital audio signals
The invention discloses a method for controlling the level of a digital audio signal. The method mainly comprises the following steps: searching the maximum sample absolute value and the average sample absolute value of a current-frame audio signal by taking each frame of audio signal as the unit, comparing the maximum sample absolute value of the current-frame audio signal with the maximum sample absolute value of a previous-frame audio signal, judging the signal strength change tendency so as to obtain different first-order recursive smooth filter parameters, adjusting the maximum sample absolute value of the current-frame audio signal, obtaining an expected gain by utilizing an expected sample absolute value, and finally, obtaining a practical gain adjustment value of the current-frame audio signal in combination with a first-order recursive smooth filtering theory. According to the invention, the strength change of a signal source is judged according to the maximum sample absolute value, the sample absolute average value, the expected level and the pre-set parameters of a voice-frame signal; configuration parameters are updated; the gain value is obtained in combination with first-order smooth filtering; therefore, the algorithm complexity is reduced; the self adaptability of an algorithm is improved; and distortion rate and volume requirements of output audio signals can be satisfied.
Owner:HUNAN GOKE MICROELECTRONICS

Hybrid power filter harmonic current detection method based on generalized weighted morphological filtering theory

InactiveCN103901255AAccurate detectionAchieve minimal error compensationCurrent/voltage measurementAlgorithmLow-pass filter
The invention provides a hybrid power filter harmonic current detection method based on the generalized weighted morphological filtering theory. The method includes the steps of firstly, selecting main structure elements and driven structure elements; secondly, constructing a master and slave opening-closing iteration morphological filter and a master and slave closing-opening iteration morphological filter; thirdly, adding the product of F[oc](n) and the sine value of the base wave positive sequence voltage to the product of F[co](n) and the cosine value of the base wave positive sequence voltage so as to obtain the direct current component of the base wave positive sequence current; fourthly, conducting dq coordinate inverse conversion and alpha beta coordinate inverse conversion on the direct current component, obtained in the third step, of the base wave positive sequence current so as to obtain a base wave positive sequence current signal, and subtracting an input signal from the base wave positive sequence current signal to obtain a harmonic current signal. According to the method, the harmonic current can be accurately detected, a traditional low-pass filter is replaced by the generalized weighted morphological filtering link, and the minimum error compensation is achieved. Simulation and experiment results show that the method has the advantages of being high in detection accuracy, good in compensation effect, and the like.
Owner:HUNAN UNIV OF TECH

Radiation source individual characteristic enhancement method based on time-varying filtering theory

ActiveCN110147848AIndividual identification facilitatesEnhancement of individual characteristicsCharacter and pattern recognitionFiltering theoryFilter algorithm
The invention discloses a radiation source individual characteristic enhancement method based on a time-varying filtering theory, and relates to a radiation source individual characteristic enhancement method. The objective of the invention is to solve the problems of low individual identification accuracy of an existing radiation source and identification failure caused by change of main signal parameters. The method comprises the following steps of: 1, performing time-frequency distribution calculation on a multi-component signal, and extracting time-frequency information to obtain time-frequency information of each signal component in a main signal component; 2, recovering and separating signal components in the main signal components one by one based on a time-varying filtering algorithm of order time-varying short-time fractional Fourier transform to obtain an estimation result of the sum of the main signal components; 3, subtracting an estimation result of the sum of the main signal components from the radiation source signal to obtain a residual component of the multi-component signal; 4, performing feature extraction on the residual component, and constructing a feature vector; and 5, inputting the constructed feature vectors into a classifier, and outputting a classification and recognition result. The method is applied to the field of radiation source individual characteristic enhancement.
Owner:HARBIN INST OF TECH

Real-time residual life prediction method of gear based on multi-degradation monitoring

ActiveCN110174261ARemaining Life PredictionMachine part testingNormal densityFeature extraction
The invention relates to a real-time residual life prediction method of a gear based on multi-degradation monitoring, and belongs to the technical field of mechanical reliability. The method comprisesthe implementation steps of: (1), monitoring degradation of a gear in a main test gear box in real time by utilizing an acceleration sensor and a noise sensor; (2), performing characteristic extraction and recession evaluation on the degradation state of the gear; (3), respectively modelling the vibration acceleration and noise of the gear box by adopting kernel estimation and random filtering theory methods, obtaining the residual life probability density function of the gear box, and obtaining a single-degradation residual life edge distribution function; (4), representing the random correlation between the vibration acceleration and the noise of the gear box by utilizing a Copula function, and obtaining a joint distribution function of the residual life of the gear box; and (5), obtaining a residual life joint probability density function thereof according to the residual life joint distribution function of the gear box, and finally, obtaining the residual life prediction value ofthe gear box. The method disclosed by the invention has the advantages that: the degradation state and the real-time residual life of the gear are effectively predicted; and basis is provided for preventative maintenance of the gear.
Owner:TAIYUAN UNIVERSITY OF SCIENCE AND TECHNOLOGY

Continuous tracking method suitable for target grabbing of underwater robot

ActiveCN111105444ARich collection of training samplesObject grabbing is reliableImage enhancementImage analysisFeature extractionAlgorithm
The invention relates to a continuous tracking method suitable for target grabbing of an underwater robot, and belongs to the technical field of visual target tracking. The method comprises the stepsof establishing a kernel-related motion model; performing HOG feature extraction; establishing an appearance model; and updating and iterating the model. According to the invention, based on the kernel correlation filtering theory, dense sampling is realized through cyclic displacement of base samples, so that a richer training sample set is extracted, HOG features are extracted, the appearance model of a tracking target is established, a kernel function is introduced, so that the nonlinear regression problem is solved, the calculation efficiency is improved, whether reinitialization trackingis needed or not is judged according to a feedback result, a self-discrimination mechanism based on system confidence is provided, and continuous tracking of the target is realized. According to the method, stable tracking of the underwater target can be guaranteed, shielding and mistaken tracking conditions can be automatically judged, so that re-identification and re-tracking are realized, and continuous tracking and reliable grabbing of the underwater target are further completed.
Owner:HARBIN ENG UNIV
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