158 results about "Spectral function" patented technology

The present invention discloses an inversion method for laser radar data of atmospheric particulate matter particle size spectrum spatial and temporal distribution. The method comprises: by measuring back scattered echo signal of atmospheric particulate matters via laser radar, accurately inverting to obtain extinction coefficients of atmospheric particulate matters in three wavelengths of infrared, visible and ultraviolet bands at different heights from the ground; building lognormal distribution spectral functions of four aerosol components and parameters thereof, for obtaining refractive indexes at different bands of different aerosols and the mixing ratio of the four aerosol components in different aerosol modes; obtaining the particle size spectrum normalized at 0.55 micron of the extinction coefficient of each aerosol basic component, and comparing with a standard spectrum for authentication; and finally performing iterative calculation to the extinction coefficient spectrums obtained by laser radar surveying to obtain the aerosol mixed volume ratio of each height, thus obtaining atmospheric particulate matter particle size distribution of different heights at different times. According to the inversion method of the invention, valid data are provided for analysis and study of particle properties and variation patterns, especially, an effective means for spatial and temporal change detection for the particle-size spectrum of the atmospheric particulate matters is provided, and active three-dimensional telemetry technology suitable for atmospheric particulate matter particle size distribution is established.

The present technology relates to solid-state image sensor and an imaging system which are capable of providing a solid-state image sensor and an imaging system which are capable of realizing a spectroscopic/imaging device for visible/near-infrared light having a high sensitivity and high wavelength resolution, and of achieving two-dimensional spectrum mapping with high spatial resolution. There are provided a two-dimensional pixel array, and a plurality of types of filters that are arranged facing a pixel region of the two-dimensional pixel array, the filters each including a spectrum function and a periodic fine pattern shorter than a wavelength to be detected, wherein each of the filters forms a unit which is larger than the photoelectric conversion device of each pixel on the two-dimensional pixel array, where one type of filter is arranged for a plurality of adjacent photoelectric conversion device groups, wherein the plurality of types of filters are arranged for adjacent unit groups to form a filter bank, and wherein the filter banks are arranged in a unit of N×M, where N and M are integers of one or more, facing the pixel region of the two-dimensional pixel array.

The invention discloses an estimating method of direction of arrival of a bistatic MIMO (Multi-Input Multi-Output) radar based on a circular array, and mainly solves the problems that in the prior art, calculation is large and the direction of arrival of the circular array cannot be estimated. The realizing process comprises the steps of: 1, obtaining a cut-off Fourier coefficient of a steering vector of the array, and replacing the steering vector by the product of the Fourier coefficient and a base; 2, performing matched filtering for received data by the array to form an autocorrelation matrix and performing characteristic-decomposition for the matrix; 3, selecting a characteristic vector to form a noise sub space and obtaining a spatial zero-spectral function; 4, introducing the steering vector received to the spatial zero-spectral function, and solving an acceptance angle by polynomial rooting; and 5, introducing the acceptance angle received to the spatial zero-spectral function and solving an angle of departure by polynomial rooting. According to the estimating method of direction of arrival of the bistatic MIMO radar based on the circular array, the polynomial rooting method can be adopted to estimate the direction of arrival of the manifold MIMO radar of the circular array, spectrum peak search is avoided, calculation is low, and the estimating method of direction of arrival of the bistatic MIMO radar based on the circular array can be applied to estimating the direction of arrival of the bistatic MIMO radar.

The invention discloses a method for estimating the direction of arrival of MIMO radar based on a nested array, which mainly solves a problem that the early radar is low in resolution for the direction of arrival and small in number of recognized signal sources. Implementation of the method comprises the steps of 1) building a nested array based MIMO radar model, and acquiring a target return signal; 2) performing snapshot sampling, matched filtering and vectorization on the target return signal in sequence, and acquiring vectorized receiving data y; 3) estimating a covariance matrix Ryy of the receiving data y, and performing vectorization on the covariance matrix Ryy to acquire an observation vector z; 4) removing repeated elements of the observation vector z to acquire virtual differential array receiving data z1; 5) dividing the virtual differential array receiving data z1 into N1 pieces of subarray receiving data, and acquiring a rank-recovery receiving data covariance matrix Rss; 6) performing eigenvalue decomposition on the rank-recovery receiving data covariance matrix Rss to acquire a noise subspace EN; and 7) acquiring the direction of arrival according to a spectral function formed by the noise subspace EN. The method disclosed by the invention improves the degree of freedom and the resolution of an MIMO radar system, and can be applied to radar target orientation detection.

The invention provides a single dipole polarization sensitive array dimensionality reduction DOA estimation method in a multipath interference environment. The array employs single dipoles concurrent with the edge of a circumference to from a uniform circular array structure, can simultaneously perform azimuth angle and elevation angle two-dimensional estimation and can effectively fight multi-path interferences to realize mathematical modeling of narrowband signals received by a uniform circular array concurrent array; then according to a matrix rank loss principle, the four-dimensional spectral function of the polarization MUSIC (multiple signal classification) algorithm is subjected to dimensionality reduction processing to construct a spatial spectral function so as to realize the fast search of spatial two-dimensional angles. Compared with polarization sensitive array DOA and polarization parameter combined estimation methods, the dimensionality reduction DOA estimation method of the invention can realize rapid estimation of signal source angles under the condition of not increasing hardware demands, receive and utilize the polarization characteristics of signal sources and interference sources to effectively distinguish objects and interferences to realize object estimation in a complex environment and has a certain engineering application value.

The invention discloses an OFDM-based high-resolution radar communication integration waveform optimization method. The method comprises steps: a radar transmission end adopts a pulse transmission mode to obtain a signal transmitted by a radar transmission end, the signal is transmitted to a communication end and a radar receiving end respectively, information demodulation is carried out after the signal arrives at the communication end, a signal after information demodulation is obtained, pulse compression processing and communication information compensation are respectively carried out on an echo signal for the signal received by the radar receiving end, a target estimation range corresponding to a target and an echo signal after communication information compensation are obtained respectively, decorrelation processing is carried out on the echo signal, an average value for multiple time sub arrays is obtained, MUSIC algorithm is used for calculating a spectral function related to a target range and a target speed in the average value, a target range with range ambiguity and a target speed without ambiguity corresponding to the target are further obtained, range ambiguity solution processing is carried out on the target range with range ambiguity, and a real target range corresponding to the target is obtained.

The invention discloses a method for detecting a printing color by using complex frequency spectrum color feature numerical values, comprising the following steps of: measuring the color of a printing matter through a visible spectrophotometer to obtain a spectrum function, and then calculating according to a complex frequency spectrum chromatic diagram and a color feature numerical value calculating method to obtain the complex frequency spectrum color feature numerical values such as a complex frequency spectrum color phase value H, a complex frequency spectrum brightness value L and the like; detecting a product color feature numerical value in real time in the printing and producing processes, and carrying out holographic detection and adjustment on the color and the contrast of the printing matter by utilizing the relation between brightness and the thickness of an ink layer, the relation between a color phase of a secondary color and color strength, the relation between gray level and the balance of three colors, i.e. yellow, pinkish red and green and the linear relation between comprehensive brightness and a dot area rate. Compared with the traditional detecting method, the method for detecting the printing color by using the complex frequency spectrum color feature numerical values has obvious advantages on the aspects such as data intuition, operability of method, effectiveness in use, economical efficiency of instruments, universality in popularization and the like, and particularly solves the problem that the two traditional indexes, i.e. three-color gray level balance and contrast linearization, are still judged mainly depending on vision and adjusted depending on experience.

The invention relates to a cross spectral function-based operational modal analysis experiment method. The method comprises the following steps that: (1), a beam is suspended by elastic ropes and a steel hammer is used for exerting pulsed excitation on the beam at a selected excitation point; (2), response signals generated by a reference point and a response point after the pulsed excitation are collected; (3), band-pass filtering is carried out on the collected signals; (4), a cross-power spectral function between the reference point and the response point is calculated and a matrix equation formed by data of the cross-power spectral function at different sampling moments is constructed; (5), a coefficient matrix is calculated by using the matrix equation so as to obtain a system pole; (6), a modal shape matrix and a modal participation factor matrix are identified; and (7), modal assurance criterion matrix value calculation is carried out; and when the modal assurance criterion value is in a preset reasonable range, a modal parameter of the beam is obtained. In addition, the invention also provides a cross spectral function-based operational modal analysis experiment apparatus. According to the invention, the experiment intensity and time are reduced; and the test efficiency as well as the learning effect of students is also substantially improved.

The invention discloses a three-dimensional ocean wave analogy method based on an ocean wave spectrum. The three-dimensional ocean wave analogy method based on an ocean wave spectrum includes confirming an observation time t and obtaining an ocean wave height at the moment, taking a relative calm moment of the ocean surface before the observation time t as an observation time 0 and obtaining an ocean wave height at the moment, deducing a relative correlation function of ocean waves based on considering the formation time history of the ocean waves and obtaining an attenuation weight function of the ocean waves through calculation, multiplying the ocean wave height of the observation time 0 by the attenuation weight function and superposing the result to the ocean wave height of the observation time t thus reflecting the influence of a previous moment ocean wave on the ocean wave of an observation time, changing an angle initial phase of an orientation spectral function of superposed ocean waves to imitate the changes of wind directions. Repeat the steps of the three-time dimensional ocean wave analogy method, and ocean superpositions of a plurality of moments are obtained and finally the imitation of ocean waves is obtained. The three-dimensional ocean wave analogy method based on ocean wave spectrum utilizes the steps to imitate the ocean waves. The imitated effect of the ocean waves is less in distortion compared with the prior art and fits with real ocean waves.

The invention discloses a broadband signal source positioning method based on subspace weight sparse recovery. The method comprises steps that multiple broadband signals having unknown correlation in the space are irradiated to a linear sensor array formed by multiple isotropy sensors, and a complex observation matrix is acquired according to the linear sensor array; a target signal arrival angle is estimated under a compression sensing framework according to the complex observation matrix to carry out reconstruction to acquire a first signal model; truncated singular value decomposition of the complex observation matrix is carried out to construct a weight matrix; a weight vector is calculated according to the weight matrix; dimensional reduction is carried out according to the first signal model to acquire a second signal model; the second signal model is optimized to acquire a third presentation form of the target signal under the compression sensing framework; a spectral function is calculated according to the third presentation form of the target signal under the compression sensing framework to acquire an estimate of the target signal arrival angle. The method is advantaged in that decorrelation capability of a compression sensing algorithm and estimation precision of an MUSIC algorithm are realized.

The invention provides a three-dimensional joint estimation method based on Wi-Fi channel state information (CSI). Firstly, in order to overcome the limitation of the number of antennas and the channel bandwidth to a two-dimensional joint estimation model, the obtained channel state information forms a three-dimensional matrix from three dimensions of subcarriers, the antennas and data packets; secondly, dimensional reduction processing is performed on the three-dimensional matrix, and smooth processing between the subcarriers, the antennas and the data packets is performed on the basis; and finally, signal subspace decomposition and noise subspace decomposition are performed on the smoothed matrix to construct a spectral function. Based on the spectral function, three-dimensional joint search of an angle of arrival (AoA), time of flight (ToF) and doppler frequency shift (DFS) is performed. A designed three-dimensional joint estimation algorithm can still achieve high estimation precision under the conditions of a small number of antennas and a narrow channel bandwidth, and provides a theoretical basis for application such as accurate indoor tracking and positioning.

The invention discloses a multi-objective angle ambiguity resolving method based on a rotating interferometer. The multi-objective angle ambiguity resolving method mainly solves the problem that two-dimensional angle estimation of multi-objective signal sources working at the same frequency and same time cannot be solved in the prior art. The multi-objective angle ambiguity resolving method is implemented by the steps of: acquiring a phase difference matrix between array elements of a multichannel rotating interferometer; acquiring interference data matrixes received by the multichannel rotating interferometer at different moment during the rotation process; performing forward spatial smoothing processing on the data matrixes, and calculating smoothed signal autocorrelation matrixes; performing eigenvalue decomposition on the autocorrelation matrixes, calculating a spectral function, and acquiring an angle ambiguity curve distribution diagram through spectrum peak searching; and projecting angle ambiguity curves into a parameter space, and accumulating parameters to obtain two-dimensional angle estimation of different objectives. The multi-objective angle ambiguity resolving methodcan simultaneously resolve ambiguity of two-dimensional angles of different objectives, calculates unambiguous two-dimensional angle information of each objective, and is used for estimating two-dimensional angles of satellite-borne rotating interferometers in space electronic reconnaissance.

The invention discloses a multipath utilization-based beam forming method. With the method adopted, the problem that multipath coherent signals cannot be effectively received in a low-altitude multipath environment in the prior art can be solved. The implementation process of the method includes the following steps that: an array radar acquires echo signal data, and solves a received signal covariance matrix Rxx; Toeplitz covariance matrix reconstruction is performed on the received signal covariance matrix, so that a new covariance matrix R is obtained; eigenvalue decomposition is performed on the reconstructed variance matrix, so that a noise subspace EN is obtained; a spatial spectral function S(theta) is formed according to the noise subspace; an angle corresponding to the peak value point of a spectral peak is found according to the spatial spectral function, namely the angle of a target is estimated; and with the estimated target angle adopted as a beam direction, beamforming isperformed. According to the method of the invention, with the estimated target angle adopted as the beam direction, beamforming is performed, and therefore, the multipath coherent information can be effectively utilized to improve the signal multi-noise ratio of echo signals. The method can be used for the effective reception of multipath coherent signals in a low-altitude multipath environment.

The invention belongs to the technical field of radars and discloses a method for direction of arrival estimation of a coherent source of a single-base MIMO radar. The method can be used for goal orientation and tracking of the single-base MIMO radar with any array manifold. The method is implemented in the following steps: step 1, a guiding vector of the single-base MIMO radar is written according to the array manifold; step 2, an M-dimension Vandermonde vector is set, and a transfer matrix G is obtained; step 3, a transformed guiding vector is obtained through a smooth transformation matrix F; step 4, matched filtering is conducted on received data of the MIMO radar, the received data obtained after matched filtering are recorded as X(k), transformed data Y(k)=FGX(k) are obtained through the transfer matrix G and the smooth transformation matrix F, and then an autocorrelation matrix is formed; step 5, eigen-decomposition is conducted on the autocorrelation matrix, and then a noise subspace is formed; step 6, a space zero spectral function is formed through the noise subspace; step 7, the polynomial rooting method is adopted to obtain a target azimuth angle.

The invention discloses a method for extracting the characteristics of infrared spectrums for highly precisely distinguishing the varieties, the producing areas and the growth patterns of Chinese herbal medicine, which comprises the steps of obtaining the infrared spectrums of the Chinese herbal medicine samples of different varieties, preprocessing the infrared spectrums, classifying the Chinese herbal medicine samples according to the producing areas and the growth patterns thereof, calculating the spectral functions on differences of the Chinese herbal medicine samples of same and different varieties, obtaining the characteristic vectors of multiple Chinese herbal medicine samples, reducing the dimensionalities of the characteristic vectors and optimizing the distribution of the characteristic vectors so as to extract the characteristics of the infrared spectrums.

The invention discloses an estimation method for the arriving direction of a monostatic MIMO radar based on random array manifolds. The method mainly solves the problems that an existing technology is only suitable for linear arrays and large in calculated quantity. The method comprises the steps that 1) the guide vector quantity of the monostatic MIMO radar is written according to the array manifolds; 2) manifold spreading is carried out on the guide vector quantity of the MIMO radar to obtain the Vandermonde guide vector quantity, guide vector quantity transfer is conducted by means of a spatial smoothing thought, and a transfer matrix from the MIMO guide vector quantity to the guide vector quantity after transfer is evaluated; 3) a receiving array and a transmitted waveform are utilized to carry out matched filtering to form an autocorrelation matrix; 4) characteristic decomposition is conducted on the autocorrelation matrix to obtain an eigenvalue and an eigenvector, and the eigenvector is selected to form a noise subspace; 5) the noise subspace is used for forming a space zero spectral function, and a polynomial rooting method is adopted to obtain an azimuth angle. The method can achieve quick estimation on the arriving direction of the monostatic MIMO radar based on the random array manifolds, is small in operation quantity, and can be used for target locating and radar tracking.

The invention is to provide a single dipole polarization sensitive rotation array DOA and polarization parameter joint estimation method. The method is characterized by, to begin with, carrying out mathematical modeling on an array receiving signal of a polarization sensitive rotation array; and then, modifying an expression of a steering vector in a spectral function of a MUSIC algorithm, thereby realizing joint estimation of incident signal DOA and polarization parameters by utilizing the MUSIC algorithm. The rotation array not only can be constructed by utilizing the single dipole polarization sensitive rotation array, but also can be constructed by utilizing any polarization sensitive antenna unit or combination, and has high portability. The array can effectively reduce the number of channels of the system, and greatly reduces cost of the system; and with fewer array elements, the problem of channel inconsistency due to larger number of array elements can be prevented effectively.

The invention discloses a blind channel estimation method based on the cyclostationarity of OFDM signals, which has the advantages that the two methods are used for analyzing the z transformation of the time delay variable Tau in the periodic spectral function of OFDM-received signals based on one fixed cycle frequency and realizing the accurate estimation of the channel information through selecting two different related values of the z transformation of the delay variable Tau, finally using the information containing the channel amplitude and the minimum phase and combining the current least square method. The two methods only use the spectral information of one cycle frequency, so that the number of the cycle frequencies is reduced and the spectral resource utilization rate is effectively improved, thereby improving the accuracy of the channel estimation. By the emulation verification, the performance of the method is obviously superior to that of the traditional blind channel estimation method.

The invention proposes a three-dimensional wind speed and direction measuring method based on a multiple signal classification algorithm. The method comprises the following steps: arranging ultrasonicsensors in a certain manner, and establishing an appropriate mathematical relationship between the speed, pitch angle and azimuth information of wind in a three-dimensional space; calculating time delay information when each sensor receives the information; and using the multiple signal classification algorithm to carry out subspace classification on a covariance matrix of information data received by a sensor array, calculating a spectral function and searching for a spectral peak value to obtain information about the speed, azimuth and pitch angle of the wind, so that the wind in the three-dimensional space can be accurately measured. The three-dimensional wind speed and direction measuring method based on the multiple signal classification algorithm provided by the invention does not rely on a time difference that an actual signal arrives at each sensor in the case of downwind and headwind, but uses a mathematical relationship between a wind vector and each sensor to calculate thedelay of an emission signal arriving at each receiving sensor. The method is simple to implement, does not require timing, and is less influenced by human and environmental factors.

The invention provides a filter parameter optimization method based on visible light communication, comprising: firstly utilizing a spectrometer to detect the spectrum data of each monochromatic light, and employing a gauss or Lorentzen function for fitting to obtain a spectral fitting function; in dependence on a real system, determining the spectral function of a bias light and the total noise power of a receiving terminal; using the signal to interference ratio of each color light at the receiving terminal as an objective function, and meanwhile determining constraint conditions of filter parameters; first using a signal to interference ratio function to solve the partial derivative of each variable, and setting a partial derivative result to be zero, then fixing a variable, and optimizing another variable under the constraint conditions, and successively performing rounds of iteration to obtain the optimal solution of the filter parameters; and respectively solving objective functions of color lights to obtain the optimal value of parameters of each colored filter. The method is suitable for a plurality of filters, has a fast convergence rate in operation, and can better reduce interference among light colors.

The invention provides multispectral living fingerprint identification equipment and an identification method. The equipment comprises plain glass, a light source module, an image acquisition module and a control module, the light source module is used for providing light of multiple different wave bands. The control module is used for sequentially selecting light of each wave band according to apreset time sequence and irradiating the light to the plain glass; the image acquisition module is used for acquiring a fingerprint image of a tested target on the plain glass under each wave band andsending the fingerprint image to the control module; the control module is also used for carrying out fingerprint identification according to the fingerprint image, synthesizing the fingerprint imageinto a multispectral image, analyzing the multispectral image to obtain a spectral function of the detected target fingerprint, and judging whether the detected target fingerprint is a real fingerprint or not according to the spectral function of the detected target fingerprint. The equipment can effectively carry out living body detection on fingerprints, and is high in detection precision and high in accuracy.