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380 results about "Fast algorithm" patented technology

High-dynamic weak-signal rapid capture method for direct sequence spread spectrum system

The invention discloses a high-dynamic weak-signal rapid capture method for a direct sequence spread spectrum system, belonging to the field of radio communication. Because a spread spectrum carrier has a chirp signal characteristic under the condition of high-dynamic motion (high-speed and high-acceleration), the high-dynamic weak-signal rapid capture method comprises the steps of: firstly, carrying out carrier Doppler frequency compensation by using a time frequency focusing characteristic of fractional order Fourier transform; secondly, carrying out incoherent accumulation on a spread frequency signal by using an order resolving capacity of the fractional order Fourier transform; and finally, carrying out capture judgment on the signal in an order Fourier domain by using a constant false alarm rate detection technology. According to the invention, the difficulty of incapability of long-time coherent accumulation under the high-dynamic condition in the traditional Fourier transform based rapid capture method is solved; and under the condition of high dynamicity and low signal to noise ratio, the signal to noise ratio is effectively increased and the signal capture time is shortened. In addition, a rapid algorithm exists in the invention and is easy to realize on the engineering in real time.
Owner:BEIJING INSTITUTE OF TECHNOLOGYGY

Non-local image denoising method based on low rank restoration

The invention discloses a non-local image denoising method based on low rank restoration. The method comprises the steps of (1) collecting an image, (2) carrying out gray transformation on the collected image, (3) establishing a three-dimensional similarity matrix through the global search of a similar pixel block for the image which is subjected to gray transformation, then carrying out hard threshold filtering on the discrete cosine transform and Hadamard transform coefficients of the three-dimensional matrix is carried out, obtaining the initial estimation of the similar pixel block with the removal of partial noise, and improving the matching accuracy of the similar pixel block with low rank restoration denoising while removing a large part of noise, and (4) with transform domain filtering as prior knowledge, searching a similar pixel block in a search area for an initially denoised reference pixel block, then forming the similarity matrix by using a similarity block corresponding to an original image, carrying out low rank matrix decomposition on the similarity matrix, effectively separating noise and a signal, and obtaining a final denoised image. The method has the advantages of a simple and fast algorithm, a high signal-to-noise ratio and good consistency and is especially suitable for the requirements of high quality noise reduction of large-scale images.
Owner:OCEAN UNIV OF CHINA

Unmanned aerial vehicle energy efficiency maximization resource distribution method based on physical layer safety

InactiveCN109151718AGreat safety and energy efficiencyStrong adjustment abilityParticular environment based servicesVehicle wireless communication serviceFast algorithmUncrewed vehicle
The invention discloses an unmanned aerial vehicle energy efficiency maximization resource distribution scheme based on a physical layer safety technology, so that the purpose of maximizing the safetycapacity of the ground users is achieved. The method comprises the following steps: 1, setting parameters and initializing the parameters; 2, calculating the transmission power Pi [n] corresponding to the nth moment on the basis of the flight trajectory qi [n] of the given ith iteration; 3, updating the multiplier lambda i by using a sub-gradient iteration method according to the transmission power Pi [n]; 4, judging the average sending power constraint to obtain the sending power Pi [n] of the ith iteration; 5, utilizing the transmission power Pi [n] obtained by iteration, and calculating the parameter optimization function S (zeta i) by means of a convex optimization algorithm to obtain a flight trajectory qi [n]; 6, judging the parameter optimization function S (zeta i), judging whether the iteration stopping condition is met or not, and if the iteration stopping condition is met, the iteration stopping condition is judged, obtaining the optimal transmission power po [n] and the flight trajectory qo [n] under the optimal energy efficiency, otherwise, continuing to circulate until the condition is met. The method has the advantages of being capable of guaranteeing safe transmission of information, fast algorithm convergence, easy implementation, and can be used for wireless communication.
Owner:NANCHANG UNIV

Image matching method, device, computer device and storage medium

The invention relates to the field of computer technology, and provides an image matching method, a device, a computer device and a storage medium. The image matching method comprises the following steps: a finger vein image to be detected is obtained and grayscale processing is performed to obtain a grayscale image; a fast algorithm is used to extract the feature points of finger vein veins in gray-scale images; a sift algorithm is used to process the feature points, and the eigenvectors of each feature point are obtained; for each feature point, the cosine value between the feature vector ofthe feature point and the feature vector of each legal feature point in the legal image is calculated; if the cosine value is less than the preset cosine threshold value, the feature point of the cosine value is confirmed as the matching point; and if the cosine value is less than the preset cosine threshold value, the feature point is confirmed as the matching point; if the number of matching points is greater than the preset threshold value, it is confirmed that the finger vein image to be detected matches the legal image. The technical proposal of the invention realizes the accurate identification and matching of finger vein patterns, thereby effectively improving the accuracy of finger vein pattern matching.
Owner:PING AN TECH (SHENZHEN) CO LTD

Optimal two-vector combination-based model predictive control method and system

The invention discloses an optimal two-vector combination-based model predictive control method and system. The method is applied to a permanent-magnet synchronous motor control system driven by a three-phase two-level inverter. A model predictive current control strategy is adopted, all two-vector combinations and resultant vector sets obtained under action time are considered at the same time, and a cost function is inspected and an optimal resultant vector is selected from all to-be-selected sets. In order to simplify the optimization process, an equivalent voltage equation is given, a sector transformation method is provided and to-be-selected two-vector combination sets are transformed into multiple fixed line segments; and a fast algorithm is given and partial complicated calculation is transformed to offline execution, so that the real-time calculated amount of the novel method is effectively reduced. The model predictive control method disclosed by the invention is simple in structure, small in real-time calculated amount and easy to implement; and the response speed of a motor is high, current ripples and distortion are small, the switching frequency is low and the dynamic and static performance of the system is excellent.
Owner:HUAZHONG UNIV OF SCI & TECH

Multi-resolution precondition method for analyzing aerial radiation and electromagnetic scattering

The invention discloses a multi-resolution precondition method for analyzing aerial radiation and electromagnetic scattering problems in electromagnetic simulation. The method is a method for generating a multi-resolution basis function by using a geometrical mode on a laminar grid constructed in a grid aggregation mode and further generating multi-resolution preconditions, wherein the multi-resolution basis function is formed by linear combination of a classical vector triangle basis function (RWG), and can be conveniently applied to the conventional moment method electromagnetic simulation program to effectively improve the behavior of a matrix formed in the moment method electromagnetic simulation process so as to realize acceleration of the iterative solution process of a matrix equation and fulfill the purpose of accelerating the moment method electromagnetic simulation process. Meanwhile, the multi-resolution pre-processing technology can also be conveniently combined with a quick algorithm such as a quick multi-pole algorithm. The method has the advantages of short calculation time and capability of ensuring high precision of the program and low demand of a computing memory, and can effectively improve the computing efficiency of the conventional electromagnetic simulation.
Owner:NANJING UNIV OF SCI & TECH

Quick algorithm for joint resource allocation in heterogeneous wireless network parallel multi-access system

The invention discloses a quick algorithm for joint resource allocation in a heterogeneous wireless network parallel multi-access system. When the joint resource allocation is performed in the heterogeneous wireless network parallel multi-access system, the bandwidth and power allocations are separated and the resource allocation is performed in turn, wherein the bandwidth allocation under the condition of equal power allocation is firstly performed; in the bandwidth allocation process, the advantage of high convergence rate of a Newton method is fully taken, thereby reducing the arithmetic complexity and increasing the arithmetic rate; and then the power allocation is performed; and if a power allocation result is a negative value, the bandwidth and the power are allocated again, thereby more fully utilizing the bandwidth and power resources as well as increasing the arithmetic efficiency and rate. By utilizing the algorithm to perform the joint resource allocation in the heterogeneous wireless network parallel multi-access system, the purpose of approaching the acquired resource allocation optimal solution to the theoretical optimum solution is achieved. The algorithm can be used for quickly allocating the joint resource in the heterogeneous wireless network parallel multi-access system.
Owner:XIDIAN UNIV

Calculation method of sound field distribution of phased array ultrasonic probe in flaw detection in multilayer medium

A calculation method of sound field distribution of a phased array ultrasonic probe in flaw detection in a multilayer medium. The method comprises the steps of: S1, modifying a Rayleigh integral expression to obtain an expression of phased array sound field transmission; S2, establishing a fast algorithm of path in an arbitrary multilayer medium; and S3, calculating chip delay time and excitation delay time: S3-1, establishing a three-dimensional system of coordinates comprising a probe wafer, a wedge and a work piece; S3-2, conducting Fourier transform on a drive signal; S3-3, forming a path matrix; S3-4, calculating a point source delay time, diffusion attenuation, and reflection and transmission through each section; S3-5, calculating sound field amplitude and phase transformation generated from a target signal, and conducting inverse transformation to obtain sound field from each point source drive signal transmitting to the target calculation point; S3-6, superimposing to obtain sound field value at the target point; and S3-7, dividing units and sequentially calculating to obtain sound field distribution in the target area. The invention can effectively assist process design and defect evaluation phased array detection of complex multilayer structure.
Owner:ELECTRIC POWER RES INST OF GUANGDONG POWER GRID +1

Car logo locating and recognizing method and system

The invention belongs to the field of pattern recognition, and particularly relates to a car logo locating and recognizing method and a system. According to the car logo locating and recognizing method and the system, car logos can be recognized. The car logo locating and recognizing method includes the steps: collecting pictures of samples of various car logos, and obtaining a template base of the car logos; adopting a fast algorithm, and extracting out a feature set of the sample picture of each car logo in the template base of the car logos; serving the feature sets as a training set, and generating a support vector machine (SVM) classifier. The method further includes the steps: collecting original images of the car logos; carrying out morphology preprocessing on the original images, and locating a candidate area of the car logos on images obtained through the morphology preprocessing; adopting the fast algorithm, and extracting out a to-be-recognized feature set of the candidate area of the car logos; adopting the SVM classifier, carrying out matching recognition on the to-be-recognized feature set, and serving a car logo which corresponds to a feature set matched with the to-be-recognized feature set as a recognition result.
Owner:信帧机器人技术(北京)有限公司

Circular synthetic aperture radar imaging method

The invention discloses a circular synthetic aperture radar imaging method, belonging to the technical field of electronic signal processing. The invention relates to a spatial remote sensing and air-to-ground observation information processing technology, in particular to an onboard circular synthetic aperture radar imaging technology. According to the imaging method, an original oblique plane echo is mapped to the ground plane by solving the inverse of a system kernel function, and the distribution of signals in a wave number domain is obtained by multiplying an azimuth frequency domain with a reference function, so that plane wave approximation is avoided, the problem that the size of an imaging area of the traditional polar format algorithm is limited can be solved, and the imaging of a large imaging scene can be realized; pseudo-polar coordinates are used for replacing rectangular coordinates as an intermediate interpolation transition matrix, and the distribution density characteristic of the signals in the wave number domain is considered, so that the interpolation precision is higher, the obtained image resolution is higher, and the high resolution imaging can be realized; the imaging process only involves one-dimensional interpolation, and fast algorithms such as chirp z transform (CZT) and inverse fast Fourier transform (IFFT) are adopted, so that the method has very high computational efficiency and can realize rapid imaging.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA
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