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130 results about "Toeplitz matrix" patented technology
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In linear algebra, a Toeplitz matrix or diagonal-constant matrix, named after Otto Toeplitz, is a matrix in which each descending diagonal from left to right is constant.
Time domain equalization using frequency domain operations
InactiveUS20050175112A1Better networkLarge capacityMultiple-port networksDelay line applicationsTime domainTime domain equalization
An equalizer for a multi carrier transmission system, converts a transmitted multi carrier signal into sampled frequency domain signals, and suppresses time domain delay dispersion, on the sampled frequency domain signals. It exploits circulant decomposition of a Toeplitz matrix to enable the computationally heavy evaluation of a matrix multiplied by a vector, to be avoided. Increased precision arises from the frequency domain processing being equivalent to a longer time domain FIR filter than is normally practical. The amount of compensation for different carriers can be adjusted, which can lead to increased precision.
Owner:PROTON WORLD INT +1
Coded image system and method thereof
ActiveUS20150139560A1Reduce numerical round-off errorQuality improvementCharacter and pattern recognitionDigital video signal modificationVisual perceptionToeplitz matrix
A coded image system enables a user to recover an object scene from an encoded image. The coded the image system comprises: a physical object scene; an encoding logic creating an encoded image, the encoding logic including a programmable aperture mask spaced a distance away from the physical object scene to encode the encoded image via a doubly-Toeplitz matrix, the doubly-Toeplitz matrix including two one-dimensional vectors; and a decoding logic operatively coupled to the programmable aperture mask to decode the encoded image recovering a visual representation of the object scene from the encoded image.
Owner:BAE SYST INFORMATION & ELECTRONICS SYST INTERGRATION INC
Method for estimating signal wave direction
InactiveCN101325807ARemove estimated effectsReduce arityDiversity/multi-antenna systemsRadio/inductive link selection arrangementsSignal waveEstimation methods
The invention provides a signal DOA estimation method. The method supposes that an unknown noise covariance matrix has a symmetrical Toeplitz matrix character; according to the difference conception of the traditional covariance matrix, an imaginary number j is introduced so that the newly constructed covariance matrix changes into a central Hermitian matrix, thereby, the character decomposition can obtain the same DOA as the incident signal numbers. The method greatly reduces the number of the antenna array element required by estimating the signal wave arrival direction, and a wave crest is only formed in the wave arrival direction of the real signal. The method can reduce cost greatly in the practical application.
Owner:PLA UNIV OF SCI & TECH
Quantum secret key distribution privacy amplification method supporting large-scale dynamic changes
ActiveCN104506313AIncrease flexibilityEasy to handleKey distribution for secure communicationCounting rateData operations
The invention discloses a quantum secret key distribution privacy amplification method supporting large-scale dynamic changes. The method includes the steps of firstly, conducting initialization, wherein the optimal operation scale m of an FFT module is calculated according to the actual running parameters of a quantum secret key distribution system when the privacy amplification method is started, and the initialization scale is an FFT operation and inverse FFT operation module of m; secondly, normalizing data, wherein the final security secret key length r is calculated according to the detector counting rate Q mu of the quantum secret key distribution system, the quantum bit error rate E mu, the corrected weak security secret key length n and the security parameter s of the quantum secret key distribution system, and normalizing an initial secret key string and a Toeplitz matrix according to the parameter m, the parameter n and the parameter r; thirdly, conducting data operation, wherein the operation process of the Toeplitz matrix and the initial secret key string is operated through the FFT technology, the first r items of the calculation result are taken to form a result vector, namely, the final security secrete key. The method has the advantages of being high in flexibility, better in processing performance, and the like.
Owner:NAT UNIV OF DEFENSE TECH
Block chain system signature method and device based on quantum key distribution
InactiveCN108737114AHigh transparencyImprove efficiencyKey distribution for secure communicationUser identity/authority verificationChain systemComputer science
The embodiment of the invention discloses a block chain system signature method and device based on quantum key distribution. The method comprises the following steps: generating transaction information by a block chain node; selecting a key from a key pool by the block chain node and generating a Toeplitz matrix, and signing the transaction information by adopting the Toeplitz matrix, wherein keys in the key pool are generated by virtue of a quantum key distribution technology; and sending the signed transaction information to other nodes in a block chain by the block chain node. By virtue ofthe technical scheme of the invention, transparency, high efficiency, safety and reliability of the block chain system can be enhanced.
Owner:天津中兴云链技术有限公司
Method of inverting nearly Toeplitz or block Toeplitz matrices
ActiveUS20050276356A1The process is simple and effectiveMinimum errorMultiple-port networksData representation error detection/correctionRadio receiverRadio reception
A method of computing an inversion (X) of a nearly Toeplitz n by n matrix (A). A perturbation matrix (E) is first determined such that the sum of the nearly Toeplitz matrix (A) and the perturbation matrix (E) is a Toeplitz matrix (T). The inversion is then solved for by solving the equation X=T−1(B+EX), where B is a vector or matrix of dimension n by m. The equation is solved by selecting an initial estimate X(0); and iteratively computing estimates of the inversion X through the recursion X(n+1)=T−1(B+EX(n)). The initial estimate X(0) may be equal to an inversion (T−1) of the Toeplitz matrix (T). In specific embodiments, the present invention may be utilized in a radio receiver to efficiently compute (1) a least-squares (LS) channel estimate, (2) minimum mean squared error (MMSE) prefilter coefficients for a decision feedback equalizer (DFE), or (3) an autoregressive (AR) noise-spectrum estimation from a finite number of observed noise samples.
Owner:TELEFON AB LM ERICSSON (PUBL)
Evaluation method of undetermined wave arrival direction of non-uniform array
ActiveCN105403874AAvoid lostReduce computationWave based measurement systemsComputation complexityObservation data
The invention discloses an evaluation method of the undetermined wave arrival direction of a non-uniform array. The problem of quite high computing complexity in the prior art is mainly solved. The evaluation method comprises steps of firstly constructing a virtual array by use of a covariance matrix for receiving array data; then obtaining observation data of a difference synthesis array by use of data of whole virtual array elements; then carrying out decorrelation by constructing a Toeplitz matrix used for observing data to replace the traditional space smooth operation and evaluating subspace of signals and noise; and at last using the subspace of the noise to construct a polynomial about a MUSIC spectrum and using the solution of the polynomial to evaluate wave arrival direction. Thus, angle grid searching with many computations is avoided; evaluation precision which is higher than that of the traditional SS-MUSIC algorithm can be obtained in a quite low computation complexity; and the evaluation method can be used for evaluating target directions.
Owner:XIDIAN UNIV
Method for quickly reconstructing magnetic resonance images on basis of adaptive structure low-rank matrixes
InactiveCN107991636AImprove reconstruction qualityImprove balanceMeasurements using NMR imaging systemsWeight coefficientResonance
The invention discloses a method for quickly reconstructing magnetic resonance images on the basis of adaptive structure low-rank matrixes, and relates to the technical field of magnetic resonance imaging. The quality of reconstructed images can be improved by the aid of the method. The method includes steps of (1), acquiring partial k spatial data; (2), solving partial derivatives and constructing Toeplitz matrixes; (3), building image reconstruction models; (4), deforming the Toeplitz matrixes and decomposing characteristic values; (5), computing weight coefficient matrixes and leading the weight coefficient matrixes into the reconstruction models; (6), introducing auxiliary variables and Lagrange multipliers and carrying out iterative solution by the aid of ADMM (alternating direction method of multipliers) algorithms; (7), judging whether convergence conditions are met by reconstruction results or not; (8), acquiring ultimate magnetic resonance images when iterative times are reached, or updating the Toeplitz matrixes by the current reconstructed images obtained by means of iteration, and returning the step (4) to continue operation. Compared with first-order and second-order structure low-rank and total-variation methods, the method has the advantage that the reconstructed images with high quality can be obtained by the aid of the method under the condition of identical under-sampling multiples.
Owner:HARBIN INST OF TECH
Seismic data reconstruction method based on matrix reduced rank
InactiveCN106646612AReduce data storageImprove rebuild speedSeismic signal processingTime domainDecomposition
The invention provides a seismic data reconstruction method based on a matrix reduced rank, and the method comprises the steps: obtaining a quadruple Toeplitz matrix built through the seismic frequency slicing data, and storing a part of rows and columns of elements of the quadruple Toeplitz matrix, so as to express the quadruple Toeplitz matrix, wherein the part of rows and columns of elements of the quadruple Toeplitz matrix comprises all different elements of the quadruple Toeplitz matrix; carrying out the reduced-rank processing of the quadruple Toeplitz matrix expressed by the part of rows and columns of elements of the quadruple Toeplitz matrix through employing a random QR reduced-rank decomposition algorithm, so as to carry out the reduced-rank processing of the quadruple Toeplitz matrix; solving the mean value of the diagonal elements of the quadruple Toeplitz matrix through a no-expansion averaging algorithm after reduced-rank processing, and obtaining the reconstruction data of the seismic frequency slicing data; carrying out the Fourier inversion of the reconstruction data of the seismic frequency slicing data, and obtaining the time domain seismic reconstruction data which is used for oil gas exploration. The method can reduce the data storage size and calculation burden, and does not reduce the reconstruction quality.
Owner:CHINA UNIV OF GEOSCIENCES (BEIJING)
Verifiable and secure privacy amplification method based on quantum key distribution
ActiveCN108599934AMeet security needsEasy to implementKey distribution for secure communicationAlice and BobLower limit
The invention discloses a verifiable and secure privacy amplification method based on quantum key distribution. The method comprises the steps of S1, generating an initial random number string W, respectively generating random number strings K<mis,A> and K<mis,B> by two communication parties (Alice and Bob) in a base comparison process of quantum key distribution, and combining the two random number strings into a random number string W=[<Kmis,A>, K<mis,B>] by the Alice; S2, verifying randomness, after an error correction phase of the quantum key distribution is finished, estimating the minimum entropy lower limit of the W relative to an attacker Eve, wherein H<min>(W|E) is greater than or equal to 1-H<2>(e); S3, calculating a final secure key length N<f>; S4, extracting a perfect random string W*, through adoption of a partial pre-shared secure key of the two communication parties, constructing a Toeplitz matrix H<R>, and extracting the perfect random number string W* from the W according to the H<R>; S5, negotiating a universal hash function H<PA> through a public channel according to the W*; and S6, respectively carrying out hash operation on error corrected key strings by the two communication parties according to the H<PA>, and generating a final secure key. The method has the advantages of verifiability, security, easy realization and simplification of quantum key distribution system design and realization.
Owner:NAT UNIV OF DEFENSE TECH
Method for fine segmentation of eye ground optic disc based on SLIC super-pixel segmentation
ActiveCN108961280AEasy to follow upTime consumingImage enhancementImage analysisEllipseMorphological processing
The invention discloses a method for fine segmentation of the eye ground optic disc based on SLIC super-pixel segmentation. The steps are as follows: super-pixel segmentation, vascular segmentation based on morphological processing and R-G double-channel color threshold segmentation are carried out on an input eye ground image, and after expansion of a connected region obtained from color threshold segmentation, a corresponding Toeplitz matrix template is selected according to the pixel coordinates of the connected region to filter an eye ground vascular image to obtain the center position ofthe optic disc; and then, a candidate area of the optic disc is extracted and the internal blood vessels are removed, threshold segmentation is carried out on the candidate area of the optic disc through a binarization method, the ROI (Region of Interest) of the optic disc ellipse is determined by using an ellipse fitting method based on least squares, super pixels with a certain overlapping areaare retained according to the SLIC super-pixel segmentation result, and thus, fine segmentation of the optic disc is completed. Through the method, automatic positioning and fine segmentation of the optic disc are realized, better contour information of the optic disc can be retained, less time is consumed, other follow-up processing of the eye ground image is facilitated, and assistant diagnosiscan be provided for ophthalmologists.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA
Coherent signal source MIMO radar angle estimation method in non-stationary noise
The present invention discloses a coherent signal source MIMO radar angle estimation method in non-stationary noise. The method concretely comprises the steps of: 1, performing system initialization;2, obtaining signal data being subjected to MIMO radar matching filter processing, and calculating a signal covariance matrix; 3, employing a conventional subspace algorithm to achieve angle estimation of an incoherent signal source; 4, constructing a new Toeplitz matrix; 5, rejecting the incoherent signal source, and obtaining a covariance matrix of the coherent signal source; 6, employing an m-Capon algorithm to perform angle estimation of the coherent signal source, and estimating a direction of arrival of a target; and 7, estimating a direction of departure of the target. The coherent signal source MIMO radar angle estimation method in non-stationary noise achieves angle estimation of the coherent signal source.
Owner:XIDIAN UNIV
Narrowband near field signal source positioning method under non-uniform noise
ActiveCN107255796ASolve the problem of non-uniform noiseEliminate direction unknownsPosition fixationEstimation methodsDirection information
The present invention relates to a narrowband near field signal source positioning method under non-uniform noise. The method comprises the steps of firstly utilizing a principal back-diagonal element for receiving an estimated value of a data array covariance matrix to eliminate the distance unknown quantity, constructing a toeplitz structure matrix, and transforming the non-uniform noise into the uniform noise; then using a direction of arrival estimation method to estimate the information source direction information on the constructed toeplitz matrix; finally, utilizing a second back-diagonal element for receiving the data array covariance matrix and the estimated value in a direction of arrival to construct the toeplitz structure matrix only containing the distance unknown quantity, and using the toeplitz structure matrix to obtain the estimated value of a narrowband near field signal source distance. The narrowband near field signal source positioning method under the non-uniform noise of the present invention effectively solves the problem that the noise is non-uniform when a near field signal source is positioned, is simple to calculate, and has good estimation performances both on the direction of arrival and the distance.
Owner:XI AN JIAOTONG UNIV
Rapid adaptive iteration method for achieving Doppler wave beam sharpening imaging
InactiveCN107402380AQuick solveReduce operational complexityRadio wave reradiation/reflectionSharpeningSelf adaptive
The invention discloses a rapid adaptive iteration method for achieving Doppler wave beam sharpening imaging. According to the invention, by use of covariance matrix rapid calculation and covariance matrix rapid inversion, super-resolution Doppler wave beam sharpening imaging of angles in forward squint regions of aircrafts like airplanes, missiles and the like is achieved, and a problem of high complexity of covariance matrix solving and covariance matrix inversion operation in the traditional direct iteration adaptive method is solved. The method is characterized in that, based on the problems of covariance matrix calculation and covariance matrix inversion in the iteration adaption, by use of properties of a Toeplitz matrix and a Hermitian matrix, the matrix is rapidly obtained by solving a row of elements; by use of the Gohberg Semencul (GS) type decomposition method, rapid solving of inverse matrix of the covariance matrix is achieved; and it is achieved that the Doppler wave beam sharpening imaging of the iteration adaptive method occupies fewer operation resources in engineering application and is quite highly efficient.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA
Method of inverting nearly Toeplitz or block Toeplitz matrices
ActiveUS7388935B2The process is simple and effectiveMinimum errorMultiple-port networksData representation error detection/correctionRadio receiverPerturbation matrix
A method of computing an inversion (X) of a nearly Toeplitz n by n matrix (A). A perturbation matrix (E) is first determined such that the sum of the nearly Toeplitz matrix (A) and the perturbation matrix (E) is a Toeplitz matrix (T). The inversion is solved by solving the equation X=T−1(B+EX), where B is a vector or matrix of dimension n by m. An initial estimate X(0) is selected and estimates of the inversion X are iteratively computed through the recursion X(n−1)=T−1(B+EX(n)). The initial estimate X(0) may be equal to an inversion (T−1) of the Toeplitz matrix (T). The present invention may be utilized in a radio receiver to efficiently compute (1) a least-squares (LS) channel estimate, (2) minimum mean squared error (MMSE) prefilter coefficients for a decision feedback equalizer (DFE), or (3) an autoregressive (AR) noise-spectrum estimation from a finite number of observed noise samples.
Owner:TELEFON AB LM ERICSSON (PUBL)
Coded image system and method thereof
ActiveUS9445115B2Reduce in quantityQuality improvementDigital video signal modificationToeplitz matrixImage system
A coded image system enables a user to recover an object scene from an encoded image. The coded the image system comprises: a physical object scene; an encoding logic creating an encoded image, the encoding logic including a programmable aperture mask spaced a distance away from the physical object scene to encode the encoded image via a doubly-Toeplitz matrix, the doubly-Toeplitz matrix including two one-dimensional vectors; and a decoding logic operatively coupled to the programmable aperture mask to decode the encoded image recovering a visual representation of the object scene from the encoded image.
Owner:BAE SYST INFORMATION & ELECTRONICS SYST INTERGRATION INC
Data encryption method, data authentication method, and related device and system
ActiveCN109274485AReduce the probability of collisionIncrease randomnessKey distribution for secure communicationData integrityBit numbering
The invention discloses a data encryption method, a data authentication method and a related deviceand system. The method comprises the following steps: determining the bit number N of the data to beencrypted; determining a bit number m of the data to be encrypted after the data to be encrypted is encrypted; selecting the m-order primitive polynomial of LFSR shift operation and obtaining the initial shift data of m bits; processing at least two submatrices to be encrypted belonging to the matrix to be encrypted and at least two random submatrices belonging to the random matrix to obtain matrix data multiplied by the matrix to be encrypted and the random matrix; Wherein, the matrix to be encrypted is an N-row 1-column matrix composed of N bits of the data to be encrypted, and the random matrix is a Toeplitz matrix of m rows and N columns composed of m + N-11-bit data, m + N-1-bit data includes the initial shift data of m-bit and N-1 bit data which should be newly generated by N-1 shiftbased on m-th order primitive polynomial. The present application is capable of improving the accuracy of data integrity authentication.
Owner:QUANTUMCTEK
Coherent signal direction finding method and system with unknown signal source number
InactiveCN104298850AEffective estimateDirection findersSpecial data processing applicationsIntermediate variableDecorrelation
The invention provides a coherent signal direction finding method and system with an unknown signal source number. The coherent signal direction finding method includes the initiating step, the fourth-order cumulant matrix calculating step, the Toeplitz matrix establishing step, the intermediate variable setting step, the power spectrum calculating step and the searching step. The method and system have the advantages that decorrelation is conducted on coherent signals by establishing the Toeplitz matrix based on fourth-order cumulant, the Toeplitz matrix is of a joint diagonalization structure, and therefore no priori knowledge about the signal source number is needed; a new cost function is designed, and therefore the direction of arrival can be effectively estimated.
Owner:HARBIN INST OF TECH SHENZHEN GRADUATE SCHOOL
Method for restoring motion blurred image based on total variational model and neutral network
ActiveCN101571948AImprove convergence speedAccurate Recovery ResultsImage enhancementPhysical realisationRestoration methodVariational model
The invention discloses a method for restoring a motion blurred image based on a total variational model and a neutral network, which mainly solves the problem existing in the prior method that the image cannot be accurately restored. The implementation process comprises the following steps of: (1) constructing a Toeplitz matrix; (2) working out gradients in horizontal and vertical directions; (3) initializing the neutral network; (4) working out a neuron output; (5) working out the output of the neutral network; (6) working out a first variation delta E1 of a network energy function; (7) if the neurons are completely updated, jumping to the step (4); otherwise, jumping to a step (8); (8) if the set iterations are reached, outputting a restoration result, otherwise jumping to a step (9); (9) working out a restoration error; (10) if the restoration error is smaller than the set error, outputting the restoration result, otherwise jumping to a step (11); (11) working out the current input bias matrix; (12) working out a second variation delta E2 of the network energy function; and (13) if the summation of the delta E1 and the delta E2 is less than 0, jumping to a step (2); if the summation of the delta E1 and the delta E2 is more than or equal to 0, jumping to the step (3); and if the delta E1 is equal to 0, outputting the restoration result. The method can obtain relatively accurate restored images, and be applied to the restoration of motion blurred images.
Owner:XIDIAN UNIV
High-speed privacy amplification method for supporting large-scale input blocks in quantum key distribution system
PendingCN111490869AReduce the finite code length effectInput length reducedKey distribution for secure communicationEncryption apparatus with shift registers/memoriesFast Fourier transformUniversal hashing
The invention discloses a high-speed privacy amplification method for supporting large-scale input blocks in a quantum key distribution system. The high-speed privacy amplification method adopts a simplified Toeplitz matrix as a universal hash function family, splits the Toeplitz matrix into a plurality of sub-blocks with the same size, and utilizes fast Fourier transform for accelerating a product of corresponding Toeplitz matrix blocks. The high-speed privacy amplification method has the advantages of better system safety, higher processing speed and the like.
Owner:广东天镝科技有限公司
A Verifiably Secure Privacy Enhancement Method for Quantum Key Distribution
ActiveCN108599934BMeet security needsEasy to implementKey distribution for secure communicationKey sizeAlice and Bob
Owner:NAT UNIV OF DEFENSE TECH
Design method of two-dimensional double prototype completely-oversampled DFT (discrete Fourier transform) modulated filter bank
InactiveCN105787204AImprove performanceRapid designCAD circuit designConstraint-based CADComputation complexityFast algorithm
The invention discloses a design method of a two-dimensional double prototype completely-oversampled DFT (discrete Fourier transform) modulated filter bank. The design of the completely-oversampled DFT modulated filter bank is realized under the condition of near perfect reconstruction. The design problem of two prototype filters is resolved into an unconstrained optimization problem, wherein an objective function is overall distortion of the filter bank, namely, a weighted sum of transmission distortion, aliasing distortion and stopband energy of the prototype filters, and the optimization problem is solved through a double-iteration mechanism according to gradient vectors of the objective function. The computation complexity is remarkably reduced according to equivalent conditions of matrix inversion and a fast algorithm of Toeplitz matrix inversion in single-step iteration. With the adoption of the method, the filter bank with better overall performance can be obtained, the computation complexity is greatly reduced, and the large-scale two-dimensional filter banks can be rapidly designed.
Owner:GUILIN UNIV OF ELECTRONIC TECH
Practical image reconstruction for magnetic resonance imaging
ActiveUS7903858B2Character and pattern recognitionDiagnostic recording/measuringFourier transform on finite groupsData reconstruction
Owner:SIEMENS HEALTHCARE GMBH
Method for amplification of long-code private key in continuous variable quantum key distribution
ActiveCN107645376ASolve the problem of long-distance transmissionEfficient use ofKey distribution for secure communicationPhotonic quantum communicationFast Fourier transformKey size
The present invention provides a method for amplification of a long-code private key in continuous variable quantum key distribution. The implementation steps of the method are as follows: the step 1:calculate an optimal private key amplification length and the size of a corresponding Toeplitz matrix according to performances of a computer; the step 1: estimating an estimated safety key length according to a corrected key length and parameters, and performing blocking processing of the corrected key and the Toeplitz matrix according to the optimal private key amplification length and the sizeof the Toeplitz obtained in the step 1; and the step 3: employing the methods of Fast Fourier Transform and the Inverse Fast Fourier Transform to perform acceleration of operation between each key after blocking in the step 2 and the corresponding Toeplitz matrix, and adding the calculated results of all the blocks to obtain a final absolutely safe keys. original code length can be very large ata long distance because of limitation of a limited code length. The method provided by the invention can perform private key amplification for long codes so as to effectively utilize computing and storage resources and improve efficiency.
Owner:PEKING UNIV +1
Under-channel direction finding system and method based on Toeplitz matrix recovery
ActiveCN110515033ASimplified direction findingImprove real-time performanceRadio wave direction/deviation determination systemsOmnidirectional antennaAlgorithm
The invention discloses an under-channel direction finding system based on Toeplitz matrix recovery. The system comprises a uniform linear array containing M omnidirectional antennas, a P-channel receiver, P-1 multipath radio frequency change-over switches, a synchronous time sequence controller, a signal acquisition processor and a spectrum estimation direction finding module. The method comprises the following steps: designing a switching mode of the multi-channel radio frequency selector switch, so that antenna array elements can be gated in a time-sharing manner; establishing a mathematical model of gating antenna array element receiving signals; calculating a covariance matrix of gating array element receiving signals; according to the Toeplitz characteristics of the covariance matrixof the uniform linear array, obtaining a covariance matrix corresponding the whole array by recovery through each calculated covariance matrix; and according to the recovered covariance matrix, carrying DOA estimation by using a covariance-based algorithm. According to the method, the characteristics of the Toeplitz matrix are utilized, the overall covariance can be recovered only by calculatingthe sub-covariance, the complexity is low, and physical hardware is easy to implement.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
Terahertz wave compression perception rapid imaging apparatus based on rotation disc-like mask plate
InactiveCN106595856AEnables continuous rotation measurementShorten the timeRadiation pyrometrySpectrometry/spectrophotometry/monochromatorsRapid imagingCircular disc
The invention discloses a terahertz wave compression perception rapid imaging apparatus based on a rotation disc-like mask plate. The apparatus comprises a mask plate used for realizing terahertz wave transmission, the profile of the mask plate is disc-like, a mask matrix in the mask plate is a binary Toeplitz matrix which is prepared by use of a metal sheet and comprises [0, 1], wherein "1" is corresponding to a hollow square hole and "0" is corresponding to a non-hollow square hole; the mask plate and an imaging object are arranged in parallel in an optical path, terahertz waves carrying the imaging object information realize transmission modulation after passing through a modulation window in the disc-like mask plate; and transmitted light is gathered at a focus by use of one terahertz wave paraboloidal mirror, and the intensity is detected by use of one terahertz detector. According to the invention, the sampling efficiency and the speed of terahertz compression perception can be greatly improved at a modulation phase of terahertz wave compression perception imaging, i.e., faster imaging is realized.
Owner:TIANJIN UNIV
Sparse array DOA estimation method based on PD-ALM algorithm
ActiveCN111562545AReduce mutual coupling effectsAccurate estimateRadio wave direction/deviation determination systemsEstimation methodsFull matrix
The invention discloses a sparse array DOA estimation method based on a PD-ALM algorithm. The method comprises the following steps: rearranging sampling data obtained by each snapshot of a sparse array into a toeplitz matrix xT; constructing a matrix filling model based on rank minimization, and filling the matrix xT by using the PD-ALM algorithm to obtain a full matrix x 'T, wherein the first rowof data of the matrix x' T being the sampling data after the single snapshot completion; forming a data matrix X' by all the snapshot complemented sampling data; and finally, performing DOA estimation on the data matrix X' by using a DOA estimation algorithm. According to the PD-ALM algorithm provided by the invention, a penalty decomposition method is adopted to directly solve the rank minimization problem; when the method is applied to the sparse array, the received data matrix of the full array can be well recovered under the conditions that the number of array elements is relatively small, the number of interference sources is large and the array is sparse, so that the wave direction is estimated more accurately, and the direction finding performance of the sparse array is improved.
Owner:NANJING UNIV OF SCI & TECH
Coherent signal wave direction-of-arrival estimation method and system without signal source number estimation
ActiveCN104156553AProof of validitySpecial data processing applicationsSignal waveEstimation methods
The invention provides a coherent signal wave direction-of-arrival estimation method and system without signal source number estimation. The coherent signal wave direction-of-arrival estimation method comprises the steps of initialization, covariance matrix calculation, Toeplitz matrix construction, intermediate variable construction, power spectrum calculation and searching. The coherent signal wave direction-of-arrival estimation method and system without signal source number estimation have the advantages that the signal source number does not need to be estimated, the advantages of the coherent signal wave direction-of-arrival estimation method and system without signal source number estimation are quite prominent in the actual application due to the fact that the signal source number is difficult to detect, and the effectiveness of the coherent signal wave direction-of-arrival estimation method and system without signal source number estimation is proved through simulation results.
Owner:HARBIN INST OF TECH SHENZHEN GRADUATE SCHOOL
Co-prime array coherent signal arrival angle estimation method based on electromagnetic vector sensor
PendingCN109901101AIncrease freedomHigh resolutionRadio wave direction/deviation determination systemsDecompositionEstimation methods
The invention provides a co-prime array coherent signal arrival angle estimation method based on an electromagnetic vector sensor and mainly solves a problem of information loss caused by holes in virtual arrays of co-prime arrays and estimation of coherent sources in a method in the prior art. The method is characterized in that an electromagnetic vector sensor co-prime array is constructed as areceiving array; receiving data of the electromagnetic vector sensor mutual array is divided into six sub-array data, and subarray data covariance matrix vectorization and de-redundancy are performed;receiving data of a uniform sub-array virtual array is constructed through filling array elements; a Toeplitz covariance matrix of a receiving signal of the uniform sub-array virtual array is solved;de-coherent full-rank Toeplitz matrices are obtained by arithmetic averaging, feature decomposition is performed, and the MUSIC method is utilized to estimate the angle of arrival of the signal. Themethod is advantaged in that angle of arrival estimation of the coherent signal can be achieved if the number of signal sources is greater than the number of physical array elements, and estimation accuracy and the estimated number of arrival angles are improved.
Owner:XIDIAN UNIV +1
Wavelet transform modulation system based compressed sensing time-domain channel estimation method
ActiveCN107634922AEliminate Interfering ICIImprove accuracyMulti-frequency code systemsTransmitter/receiver shaping networksTime domainComputation complexity
The invention discloses a compressed sensing time-domain channel estimation method for a wavelet transform modulation system. The method comprises the steps of selecting a suitable wavelet base function based on a channel estimation condition, adopting time-domain block-type pilot insertion, performing IDWT on a signal to finish modulation, building a measurement matrix by adopting a standard Toeplitz matrix, performing time-domain channel estimation by using a compressed sensing technology, and adopting Fourier transform after channel impulse response estimation to simplify a channel solutionprocess. For a wavelet transform modulation system, ICI (Inter-Carrier Interference) and ISI (Inter-Symbol Interference) of each sub-channel can be removed efficiently by utilizing the wavelet base function, and the channel estimation accuracy is improved; the number of measurement values required by channel estimation is reduced by adopting the compressed sensing time-domain channel estimation,and the calculation complexity and cost are reduced; the data signal part is solved by adopting the FFT, so that massive operation caused by wavelet change is avoided, limitations caused by wavelet transform is overcome, and the wavelet transform modulation system is enabled to have a wider application scope.
Owner:NANKAI UNIV
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