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62 results about "Iterative thresholding" patented technology

Non-contact contact line geometrical parameter detecting method

The invention discloses a non-contact contact line geometrical parameter detecting method. The method includes a first step of collecting high-definition images at equal time intervals by means of collection of control signals and finishing image preprocessing by means of the median filtering technique, the image graying technique and the like, a second step of locating a laser spot center point and extracting a coordinate of the center point by means of the iterative thresholding algorithm and a method of removing isolated noise in mathematical morphology, a third step of extracting a matched target region and detecting a transverse gray singular value of the target region, a fourth step of giving the wire height and a stagger value of a contact line by means of conversion from an image coordinate system to a camera coordinate system and from the camera coordinate system to a detection vehicle coordinate system, and compensating vibration of a vehicle body, and a fifth step of giving precise detection values of the wire height and the stagger value and displaying information of a plurality of parameters in a developed graphic monitoring interface. The method effectively improves detection efficiency of geometrical parameters of a contact net, simplifies the algorithm, improves precision of fault detection, and specifically improves safe reliability of the contact net of a high-speed train.
Owner:SOUTHWEST JIAOTONG UNIV

Multi-target tracking method integrating obvious characteristics and block division templates

ActiveCN104091348AImprove the ability to adapt to scene lighting changesPrecise positioningImage analysisMulti target trackingLevel data
The invention provides a multi-target tracking method integrating obvious characteristics and block division templates. A target motion area is detected by adoption of RGB component background difference and an iterative threshold, and the adaptive ability of a motion detection algorithm to scene illumination change is improved. Based on target area block division, a motion pixel color saliency weighted block centroid model, block centroid shifting fusion and a scale updating method, the calculation efficiency is high, the resistance to partial occlusion is high, and the similar color scene jamming ability is strong. The problem of multi-target measuring-tracking distribution is solved by adoption of two-level data association, and an occluded local area can be accurately positioned. Therefore, adaptive template updating is guided by an occlusion matrix, a reliable global centroid transfer vector is obtained by making use of effective colors and motion information of blocks, and finally, continuous, stable and fast multi-target tracking in complex scenes is realized. The multi-target tracking method integrating obvious characteristics and block division templates is applied to fields like intelligent video surveillance, in-air multi-target tracking and attacking, and multi-task tracking intelligent robots.
Owner:南京雷斯克电子信息科技有限公司

Side lobe suppression method and array sparse method for multi-beam imaging sonar sparse array

ActiveCN108919199AEnhanced inhibitory effectAvoid the problem of sparse solutions falling into local optimumAcoustic wave reradiationSparse methodsLinear regression
The invention discloses a side lobe suppression method and an array sparse method for a multi-beam imaging sonar sparse array. A sparse optimization problem of an array antenna is transformed into a linear regression problem of a sparse matrix, combination learning is carried out by taking the reconstruction of multiple beam direction patterns with different pointing directions as a target task, and a sparse semicircle array model for multi-task learning is established; based on the performance requirement of a preset main side lobe, a norm regular term of 1<1 / 2> of a weighted coefficient matrix is introduced on the basis of a least squares loss function, an iterative threshold converged method and an accelerating gradient descent method are used for solving an optimal weighting coefficient, and a weighting coefficient which minimizes a side lobe peak level is solved at the same time while optimizing the position of the sparse array. According to the side lobe suppression method and the array sparse method for the multi-beam imaging sonar sparse array, the problem that the sparse solution falls into the local optimum due to the mismatching of array position and weight vector is avoided, and peak side lobe levels of multiple beams formed by the array after sparseness is effectively reduced.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Compressed sensing method for multi-source impact load identification of mechanical structure

InactiveCN105912504AEfficient solutionInsensitive to initial conditionsComplex mathematical operationsThe chokesEngineering
The present invention relates to a compressed sensing method for multi-source impact load identification of a mechanical structure for solving ill-posed natures of the multi-source impact load identification inverse problem of a highly underdetermined system. The method comprises the following steps of (1) measuring a frequency response function between an action point of impact load of the mechanical structure and a response point of the mechanical structure, and furthermore constructing a sensing matrix; (2) measuring signals generated by dynamic load of the structure by using a sensor; (3) constructing an underdetermined equation of the multi-source impact load identification; (4) constructing an L1-norm-based compressed sensing convex optimization model of the multi-source impact load identification; and (5) solving the compressed sensing optimization model by using a two-step iteration threshold algorithm, and obtaining a compressed sensing solution of multi-source impact load. Time and space combined sparsity of the impact load is fully utilized, the method is suitable for identifying and positioning the multi-source impact load acting on the mechanical structure, and the choke point that the underdetermined system cannot be solved by a traditional regularization method based on L2 norm is overcome.
Owner:XI AN JIAOTONG UNIV +1

Automatic design method and device of superconducting quantum chip readout cavity and storage medium

The invention provides an automatic design method and device for a superconducting quantum chip reading cavity and a storage medium. The method comprises the following steps: determining the length of a CPW resonator according to the initial design frequency of a readout cavity; configuring a layout template and a simulation template, wherein the layout template and the simulation template are used for configuring geometric figure coordinates and size parameters of the CPW resonator and reading modeling parameters and simulation parameters of the cavity; constructing a simulation model of the readout cavity with the interdigital capacitor structure based on the layout template and the simulation template, performing spectrum scanning analysis, and determining simulation frequency; in response to the situation that the difference value between the simulation frequency and the initial design frequency is larger than an iteration threshold value, the initial design frequency is adjusted with a preset frequency offset, and the layout template and the simulation template are updated; and performing iterative analysis based on the updated layout template and the simulation template, and outputting the current layout template in response to the condition that the difference value between the obtained simulation frequency and the initial design frequency is less than or equal to an iterative threshold value. According to the method, the simulation model can be quickly generated, and a more accurate read-out cavity layout can be obtained.
Owner:SUZHOU LANGCHAO INTELLIGENT TECH CO LTD

Automatic baseline correction method for infrared spectroscopy

The invention discloses an automatic baseline correction method for infrared spectroscopy. The automatic baseline correction method comprises the following steps: A1, preparing a to-be-detected sample; B1, acquiring an infrared spectrum of the to-be-detected sample by using a spectrograph, and preprocessing the spectrum to obtain the original absorbance spectrum; C1, for spectral intensity Y=[y1, y2...yN] in the original absorbance spectrum at equal interval, performing average minimum updating on the original absorbance spectrum, and obtaining the spectral intensity Y1=[y1,...yi+1] of the absorbance spectrum after the first update; D1, calculating the sum of range differences, namely Sabs(1) =Sigma of an absolute value of (Y-Y1); E1, repeating the step C1 for performing iterative computations for n times, updating the Y1 to obtain Y2, deducing the rest to obtain the Y1, Y2...Yn, further performing iterative computations on the step D1 to obtain Sabs(n), then calculating until the deltaSabs(n-1)/Sabs(n) is less than or equal to an iterative threshold lambda, and stopping calculating to obtain a baseline Yn of the absorbance spectrum, wherein n is more than 2; and F1, subtracting the baseline from the original absorbance spectrum, thereby obtaining the corrected absorbance spectrum.
Owner:HEFEI INSTITUTES OF PHYSICAL SCIENCE - CHINESE ACAD OF SCI

Raft culture area extraction method based on SAR image of Gaofen-3 satellite

The invention discloses a raft culture area extraction method based on a Gaofen-3 satellite SAR image. The method comprises the following steps: firstly, acquiring Gaofen-3 satellite SAR image data including a research area; performing feature extraction on the SAR image data to obtain a plurality of extracted features; performing feature screening on the extracted features to obtain a plurality of effective features capable of reflecting the difference between the raft culture area and seawater; based on the plurality of effective features, using an iterative threshold algorithm to perform preliminary extraction of the raft culture area; and performing post-processing on the preliminary extraction result by using a density clustering algorithm, intersection and union set reconstruction and a morphological processing method, and extracting the raft culture area. According to the method, multiple features extracted from the SAR image of the Gaofen-3 satellite are used for extracting the raft culture area together, and then the iterative threshold method and the density clustering are combined, so that the influence of SAR image speckle noise can be reduced, and large continuous rows of raft culture areas can be accurately extracted.
Owner:NATIONAL MARINE ENVIRONMENTAL MONITORING CENTRE

Bunching SAR compressed sensing imaging method based on approximate observation matrix

The invention relates to a bunching SAR compressed sensing imaging method based on an approximate observation matrix. The bunching SAR compressed sensing imaging method comprises the following steps:1, obtaining a matrix form of distance-direction scale transformation based on a polar coordinate format algorithm of scale transformation; 2, obtaining a matrix form of azimuth scale transformation based on the polar coordinate format algorithm of scale transformation; 3, deriving a matrix expression form of a polar coordinate format algorithm imaging process according to results of the step 1 and the step 2; 4, deriving a signal model of an inverse imaging process according to a signal model of a radar projection matrix obtained in the step 3; and 5, constructing a CS reconstruction model byusing a PFA imaging process and an inverse imaging process obtained in the above steps and an iterative threshold shrinkage algorithm based on the approximate observation matrix. According to the method, sparse constraint is carried out on the PFA imaging process, the application range of PFA imaging in the SAR field is wider, and compared with a traditional accurate measurement matrix, the calculation complexity and the storage memory are greatly reduced.
Owner:NANJING UNIV OF POSTS & TELECOMM

Docking recovery integrated navigation method based on improved Gaussian distance iterative algorithm

The invention discloses a docking recovery integrated navigation method based on an improved Gaussian distance iterative algorithm. The docking recovery integrated navigation method comprises the following steps: 1) segmenting a track of an AUV into a plurality of connected straight line segments; 2) calculating the coordinate of each position point by utilizing dead reckoning to obtain a coordinate equation set; 3) linearizing the error by using Taylor series expansion, setting a position initial value and an iteration threshold of the AUV, solving a correction amount of the AUV position by using a least square method, comparing the correction amount with the iteration threshold, and stopping iteration if the correction amount is less than the iteration threshold; 4) if the correction amount is greater than an iteration threshold, updating the step length by adopting a trust region method to continue iteration; 5) solving the coordinate of the last point of the straight line segment as the initial point of the next straight line segment, and repeating the above steps for iteration. The method can effectively correct the speed and position errors of the AUV, enables the whole system to have higher filtering precision and stability, and provides guarantee for the safe recovery of the AUV.
Owner:JIANGSU DIYI GROUP

Method for reducing peak-to-average power ratio of filter bank multicarrier system

The invention provides a method for reducing the peak-to-average power ratio of a multi-carrier system of a filter bank. The method comprises the following steps: setting an initial amplitude limiting amplitude A (1), the maximum number of iterations Q, a peak regeneration suppression factor xi, a penalty factor eta and a search step length rho; shearing the original signal, wherein the processed signal can be expressed as Sn after being processed by the FBMC-OQAM system, the FBMC-OQAM signal iteration amplitude limiting recursion updating formula can be expressed as the conversion of the shearing noise into the frequency domain signal to solve the optimal convergence factor mu; solving the optimal value A (i) of the amplitude limiting threshold value; and letting i = i + 1, repeating the above steps, and entering the next round of loop iteration until the algorithm converges. According to the method, a system model of the reserved subcarriers of the FBMC-OQAM system is constructed, a self-adaptive subcarrier reservation algorithm is provided based on essential reasons of the FBMC-OQAM and in combination with signal structure characteristics of the FBMC-OQAM, the PAPR of the system is reduced with a small number of iterations by performing self-adaptive learning on input data and adjusting an iteration threshold value and an amplitude limiting factor, and signal distortion is not caused.
Owner:上海微波技术研究所(中国电子科技集团公司第五十研究所)

SAR non-sparse scene imaging method based on mixed sparse representation

The invention provides a non-sparse scene SAR imaging method based on mixed sparse representation. The method includes the following steps of: 1, respectively carrying out random down-sampling in a range direction and an azimuth direction on SAR echoes of a non-sparse scene; 2, constructing a linear frequency modulation scaling imaging operator and an inverse imaging operator, and constructing a two-dimensional compressed sensing optimization model based on the approximate observation model; and 3, solving the constructed optimization model, firstly initializing the non-sparse SAR scene, performing point, line and surface decomposition on the scene, then performing curvelet transformation on a line component, performing wavelet transformation on a surface component, and then sequentially reconstructing the point, line and surface components through an iterative threshold algorithm until the algorithm converges; and finally, combining the obtained point, line and surface components to obtain a final reconstructed SAR image. According to the method, SAR imaging is carried out on a non-sparse scene containing complex features under the condition of the down-sampling rate, the data volume during imaging of the non-sparse scene can be reduced, and meanwhile, the features of the image can be enhanced.
Owner:AIR FORCE UNIV PLA

Decoder, method and computer storage medium

The embodiment of the invention discloses a decoder. At least more than one computing unit of the decoder is used for obtaining to-be-decoded soft bit information of a variable node n in a basic matrix; judging whether the decoding iteration frequency i is smaller than a decoding iteration threshold value or not; when i is determined to be smaller than a decoding iteration threshold, judging whether the decoding layer number k is smaller than the row number a of the basic matrix or not; when k is determined to be smaller than a, determining soft bit information of the kth layer of variable node n according to the soft bit information of the (k-1) th layer of variable node n, and determining (k + 1) th layer of variable node information according to the soft bit information of the (k-1) thlayer of variable node n; determining check node information of the (k + 1) th layer according to the variable node information of the (k + 1) th layer; updating k to k + 1, and judging whether k is smaller than a or not again; and when k is determined to be greater than or equal to a, updating i to be i + 1, and re-executing the step of judging whether i is less than the decoding iteration threshold or not until i is equal to the decoding iteration threshold. The embodiment of the invention further discloses a decoding method and a computer storage medium.
Owner:ZTE CORP

Multi-iteration folding vocabulary hierarchical classification method and system

The invention relates to a multi-iteration folding vocabulary hierarchical classification method and a multi-iteration folding vocabulary hierarchical classification system. The hierarchical classification method comprises the following steps: calculating the use frequency of each to-be-classified vocabulary; arranging the to-be-classified vocabularies in an ascending order according to the use frequency of the to-be-classified vocabularies, and marking serial numbers; according to the total number of the to-be-classified vocabularies and the field to which the to-be-classified vocabularies belong, determining a level number and an iteration threshold value; initializing a candidate boundary threshold value of each level, wherein the candidate boundary threshold value of each level is the total number of the to-be-classified vocabularies; performing iterative query on the to-be-classified vocabularies according to the candidate boundary threshold value of each level, the serial number of the to-be-classified vocabularies and an iterative threshold value to obtain a boundary threshold value of each level; and obtaining hierarchical classification of the vocabulary to be classified according to the boundary threshold value of each hierarchy. According to the method, the word frequency is taken as a reference, the occurrence frequency of large-class vocabularies is higher than the occurrence frequency of small-class vocabularies, and the vocabulary hierarchy is divided in a loop iteration folding mode, so that the division efficiency is improved, and the hierarchy division is accurate.
Owner:中国人民解放军火箭军工程大学

Reflection tomography laser radar image segmentation method based on target area local enhancement

ActiveCN114782464AImprove object segmentation qualityReliable principleImage enhancementImage analysisSaliency mapBack projection
The invention provides a reflection tomography laser radar image segmentation method based on target area local enhancement. The method comprises the following steps: inputting an original image generated by a reflection tomography laser radar and obtained through filtering back projection reconstruction; removing ring artifacts in the original image through a two-dimensional low-pass filter; further performing mean filtering processing to filter noise points, and performing initial segmentation on the image after noise point filtering by using an iterative threshold method to obtain a segmented image; target region extraction is carried out on the segmented image according to the criterion that the area of the circumscribed convex polygon is minimum, and a closed target region of the circumscribed convex polygon is extracted; performing image filling on the extracted target region by adopting an image filling algorithm to obtain a target saliency map; fusing the target saliency map with the original image to obtain a fused image with an enhanced target area; and solving an optimal threshold value of the enhanced target area image by adopting an iterative threshold value method, and then segmenting the whole fused image by using the optimal threshold value.
Owner:NAT UNIV OF DEFENSE TECH
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