108 results about "Spectrum function" patented technology

An image editing application (or a blur classification module thereof) may automatically estimate a coherent defocus blur map from a single input image. The application may represent the blur spectrum as a differentiable function of radius r, and the optimal radius may be estimated by optimizing the likelihood function through a gradient descent algorithm. The application may generate the spectrum function over r through polynomial-based fitting. After fitting, the application may generate look-up tables to store values for the spectrum and for its first and second order derivatives, respectively. The use of these tables in the likelihood optimization process may significantly reduce the computational costs of a given blur estimation exercise. The application may minimize an energy function that includes a data term, a smoothness term, and a smoothness parameter that is adaptive to local image content. The output blur map may be used for image object depth estimation.

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 a multi-sound-source locating method based on a spherical microphone array, and the method comprises the following steps of firstly conducting spherical harmonics decomposition for high-order sound fields collected by a spherical microphone array, and building a noise-contained sound source signal model received by a spherical harmonics domain array; then expressing a covariance matrix of data received by the array; classifying the covariance matrix according to a subspace decomposition method to obtain two mutually-orthogonal signal subspace and noise subspace; utilizing the orthogonality of the signal subspace and the noise subspace to define a guide vector of the signal subspace, and extracting one characteristic vector of the noise subspace to build a space azimuth spectrum; and finally searching a spectrum peak position of an azimuth spectrum function, and determining a space azimuth of a sound source. The method utilizes a three-dimensional space rotary symmetric structure of the spherical microphone array to adequately sample the sound field, so that the operation quantity is remarkably reduced through the high-resolution spectrum estimation and dimensional-reduced noise subspace, the sound source azimuth is accurately estimated, and the method can be widely applied to the fields such as a voice signal processing field.

The invention provides a method for estimating parameters of a space stretching electromagnetic vector sensor array. The method comprises the steps of receiving K unrelated incoming signals through a receiving array, and constructing guide vectors of the incoming signals corresponding to the array; expressing the guide vectors of the incoming signals as a product of a spatial domain function array and a polarizational domain function vector; computing a covariance matrix of the received data; analyzing features of the covariance matrix of the received data to obtain signal subspace and noise subspace; constructing a multi-signal classified MUSIC spatial-polarizational domain combination zero spectrum function, and maximizing the spatial-polarizational domain combination zero spectrum function; performing MUSIC dimension reduction process to separate a spatial domain spectrum and a polarizational domain spectrum by means of the self-conjugate moment Rayleigh-Ritz entropy theorem, performing traversal search within value ranges of variables and estimating signal parameters. By means of the method, four-dimensional MUSIC search is transformed into two-dimensional spatial domain search and two-dimensional polarizational domain search, and therefore, calculated quantity is decreased.

The invention discloses an identification method of a low signal-to-noise ratio phase-shift keying modulating signal, which belongs to the technical field of communication. The identification method of the low signal-to-noise ratio phase-shift keying modulating signal firstly identifies a BPSK signal through a quadratic spectrum based on dislocation multiplication, then identifies a QPSK or OQPSKsignal through a biquadrate spectrum based on dislocation multiplication, and then calculates an envelope spectrum and implements optimization processing, and finally identifies the QPSK signal and the OQPSK signal through the optimized envelope spectrum. The invention provides a quadratic or biquadrate amplitude spectrum function calculation mode based on dislocation multiplication, which can effectively reduce the interference of noise to signal, thus effectively improving the recognition rate of the phase-shift keying modulating signal under the condition of lower signal-to-noise ratio; inaddition, the optimized biquadrate amplitude spectrum and envelope spectrum are adopted to further reduce the negative influences on spectrum peak searching caused by noise, thereby effectively improving the recognition rate. A simulation result indicates that the identification method of the low signal-to-noise ratio phase-shift keying modulating signal can realize recognition rate of more than 90 percent between QPSK and OQPSK when the signal-to-noise ratio is 0 dB; and the recognition rate between QPSK and BPSK can reach more than 90 percent when the signal-to-noise ratio is -7dB.

The invention aims to provide a low-complexity space target two-dimensional angle estimation method of L-shaped array MIMO radar. The method comprises the following steps that an L-shaped array is composed of two uniform linear arrays perpendicular to each other, the distance between every two adjacent array elements is a half of a wavelength, one linear array has M array elements, the other linear array has N array elements, all the array elements are receiving and sending co-located array elements, orthogonal narrow-band signals are sent, received signals are processed by means of matched filtering, and echo signals of a large-aperture virtual array are obtained; a dimensionality reduction array is designed, and dimensionality reduction is conducted on the echo signals; characteristic decomposition is conducted on a covariance matrix of dimensionality reduction signals, and a two-dimensional space spectrum function is obtained; a two-dimensional angle in the two-dimensional space spectrum function is decoupled, and space spectrum estimation is conducted on the angle of one dimension; an obtained space spectrum estimated value is substituted into the space spectrum function, and polynomial rooting estimation is conducted on the angle of the other dimension; according to the relation of trigonometrical functions, the azimuth angle and pitching angle of a target are obtained. The method greatly reduces computational complexity of algorithm, and is beneficial to real-time processing of a radar system.

The invention discloses an adaptive high-precision phase estimation method for an interferometric SAR, comprising the following steps of: structuring optimum weight vectors in combination with a Wiener filter theory, performing an eigen decomposition on an optimum covariance matrix composed of the optimum weight vectors to obtain a signal subspace and a noise subspace, adequately utilizing a corresponding pixel pair and the coherent information of the neighboring pixels thereof to structure a space spectrum function according to the orthogonality of the signal subspace and the noise subspace in a MUSIC (multiple signal classification) algorithm, and precisely estimating the interferometric phase between the corresponding pixels via a spectral peak searching. The optimum weight is obtained by only a Wiener filter without the need to determine a registration error and the direction thereof, thereby solving the problem of large computational burden in the traditional InSAR (interferometric synthetic aperture radar) interferometric phase estimation. The adaptive high-precision phase estimation method for the interferometric SAR disclosed by the invention is adaptive to the field of accurate surface parameter inversion of InSAR complex scene and the like.

The invention discloses a laser frequency spectrum retrieval method and a measurement calibration method for a molecular scattering anemometry laser radar and solves the problem that the existing anemometry Rayleigh laser radar is difficult in laser spectrum calibration. The retrieval method includes: allowing the molecular scattering light to perform convolution operation through an etalon transmittance function Ni(v) and an etalon transmittance function Fei(v), allowing the operation result to perform convolution operation with Rayleigh-Brillouin spectrum FR-B(v) to obtain the laser spectrum Fl(v), and fitting with the Gaussian function to obtain the laser spectrum function. The measurement calibration method and system is provided with an etalon controller for changing the cavity length of an etalon, the laser beams entering the etalon scan the cavity length of the etalon to obtain the etalon and molecular scattering light transmittance curve. By the method, accuracy, reliability and precision of wind retrieval are increased.

The invention relates to a spindle system operational modal analysis method based on a pulse excitation response signal cross-power spectrum function. The method comprises the following steps: 1) respectively selecting exciting points on a cutter shank of a spindle system and conducting pulse excitation on the spindle system at the selected exciting points by using a steel hammer; 2) acquiring response signals produced by a reference point and response points after pulse excitation; 3) conducting band-pass filtering on the acquired signals; 4) resolving a cross-power spectrum function between the reference point and the response points, and establishing a matrix equation formed by different sampling time data of the cross-power spectrum function; 5) solving a coefficient matrix by using the matrix equation to obtain system poles; 6) recognizing a modal shape and a modal participation factor matrix; 7) conducting modal assurance criterion matrix value calculation, and when the modal assurance criterion matrix value is within a preset reasonable range, obtaining the modal parameters of the spindle system. The spindle system operational modal analysis method based on the pulse excitation response signal cross-power spectrum function has the advantages that quick calculation can be realized, the accuracy is high, the error control effect is better, the testing strength and time can be reduced and the testing efficiency is greatly improved.

The invention belongs to the technical field of wireless mobile communication, and discloses a method for measuring an incoherently distributed signal two-dimensional DOA (direction of arrival) by using an array antenna. The method comprises the following steps of: arranging a three-dimensional antenna array consisting of two uniform circular arrays, establishing covariance matrixes of two circular array data, determining a sub-matrix and a central pitch angle initial value, establishing the covariance matrix of any circular array, establishing a pseudo noise sub-matrix, determining a two-dimensional spectrum function, and finally respectively determining a central directional angle and determining a central pitch angle. The root mean square error of the central directional angle and the central pitch angle measured by the measuring method is only about one tenth of angle spread; and the multi-dimensional spectrum search and the nonlinear optimization can be avoided; therefore, the measuring method is simple, reliable, can greatly reduce the computing capacity and processing complexity, has high measurement efficiency and precision, can be applied to an intelligent antenna system for improving the performance and the actual application value of the intelligent antenna system in a multi-path environment.

The invention provides a cantilever beam operational modal analysis experiment method, which comprises the following steps that: (1) an end point of a cantilever beam is selected to be used as an excitation point to implement pulse excitation on the cantilever beam by using a steel hammer at the selected excitation point; (2) response signals generated by a reference point and a responding point after the implement pulse excitation are collected; (3) the collected signals are subjected to band-pass filtering; (4) a cross-power spectrum function between the reference point and the response point is solved, and a matrix equation formed by data of the cross-power spectrum function in different moments is built; (5) a coefficient matrix is solved by using the matrix equation, and a system pole is obtained; (6) a modal shape and a modal participation factor matrix are identified; (7) the modal assurance criterion matrix value calculation is carried out, and a modal parameter of the cantilever beam is obtained when the modal assurance criterion value is in a preset reasonable interval. The invention also provides a cantilever beam operational modal analysis experiment device. The method and the device provided by the invention have the advantages that the fast calculation can be realized; the precision is high; a better error control effect is achieved; the test intensity and the test time can be reduced; and the test efficiency is greatly improved.

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.

A wavelength-locked loop servo-control circuit and methodology that enables real time mutual alignment of an electromagnetic signal having a peaked spectrum function including a center wavelength and a wavelength selective device implementing a peaked passband function including a center wavelength, in a system employing electromagnetic waves. The circuit comprises a mechanism for applying a dither modulation signal at a dither modulation frequency to the electromagnetic signal, and inputting the dither modulated electromagnetic signal to the wavelength selective device; a mechanism for converting a portion of the dither modulated electromagnetic signal to an electric feedback signal; a mechanism for continuously comparing the feedback signal with said dither modulation signal and generating an error signal representing a difference between a frequency characteristic of the feedback signal and a dither modulation frequency; and a mechanism for adjusting the peaked spectrum function of the electromagnetic signal according to the error signal. The center wavelength of the electromagnetic signal and the wavelength selective device center wavelength become aligned when the frequency characteristic of the feedback signal is two times the dither modulation frequency.

The invention discloses a hybrid signal DOA estimation method under the sparse Bayes learning framework and belongs to the radar signal processing technology field. The method comprises steps that firstly, a new sparse promotion prior called as a Gauss-index-chi square prior is proposed, a probability density function of the prior has a sharp spectrum peak and a heavy tail at a zero point, and sparse solution is facilitated; secondly, the prior is utilized to establish a third-order layered sparse Bayes model; thirdly, the mean value field variation Bayes theory is utilized to realize theoretical approximate posteriori distribution, alternative update iteration of each approximate variation distribution is carried out to minimize a KL distance, and estimates of model parameters are solved; lastly, a signal power spectrum function is constructed according to the estimates of the model parameters, and source number estimation and DOA estimation of a target radiation source can be acquired.

The invention relates to a method and a system for generating a double-exponential Bessel Gaussian beam, which is designed for realizing superposition of multiple Bessel Gaussian beams with differenttransverse wave vectors and specific amplitude. A linearly-polarized Gaussian beam firstly passes through a vortex phase plate, a phase factor is introduced to the linearly-polarized Gaussian beam, and a Gaussian vortex beam is generated; the Gaussian vortex beam then passes through an amplitude spatial light modulator which is loaded with at least two circular amplitude holograms, through regulating the transmittance of the circular amplitude hologram, the amplitude of the Gaussian vortex beam (the double-exponential Bessel Gaussian beam) is further regulated, and a double-exponential BesselGaussian beam angular spectrum function is generated; and finally, Fourier transform is carried out to generate the double-exponential Bessel Gaussian beam. The double-exponential Bessel Gaussian beamsuperposition flexibility is higher, and the operation of generating the double-exponential Bessel Gaussian beam is simple.

The invention belongs to the technical field of signal processing, and relates to a device and method for achieving the spread spectrum function of a spectrum analyzer. The device comprises a waveguide adaptor, a first waveguide switch, a second waveguide switch, a high-pass filter, a low-pass filter, a fundamental wave mixer, a dot frequency local oscillator and an intermediate frequency filter amplifier. The method includes the steps that firstly, FIF of the intermediate frequency range of a spread spectrum device is defined according to the coverage area of a preselector of a host, and then FLO of frequency of the dot frequency local oscillator is configured according to FRF of the frequency range of the device and the FIF; secondly, the design of the filters is optimized, wavebands are divided, the frequency conversion formula (FRF-FLO) is used for a low-frequency band, and the low-pass filter is matched; the frequency conversion formula (FLO-FRF) is used for a high-frequency band, and the high-pass filter is matched, and then the spread spectrum function of the spectrum analyzer is comprehensively achieved. According to the device and method, when the frequency range is higher than 67GHz, the spread spectrum function of the spectrum analyzer for image signal curbing can be also achieved.

The invention belongs to the radio signal positioning technical field, and especially relates to a multiple source (Direction of arrival) DOA estimation method comprising the following steps: obtaining an array reception antenna signal output vector, and building a four-order cumulant matrix according to the signal output vector; carrying out extraction smoothing for the four-order cumulant matrixso as to obtain a new four-order cumulant matrix; decomposing characteristic constants of the new four-order cumulant matrix so as to obtain characteristic vectors corresponding to a noise subspace and a signal subspace; building a space spectrum function according to the characteristic vector of the noise subspace; returning , and increasing multi-snapshot numbers so as to obtain the space spectrum function corresponding to the snapshot number; smoothing the space spectrum function corresponding to each snapshot number; determining the DOA of a space signal source via peak spectrum searching. The method builds the four-order cumulant matrix, reduces the matrix dimensions, reduces operand, carries out multi-snapshot space spectrum function smooth calculation, thus realizing more signal DOA estimation, and reducing influences on space spectrum estimation by the measuring errors.

A method of CT beam hardening calibration comprises: the step of obtaining raw data of a first phantom and a second phantom by scanning the first phantom and the second phantom respectively; the step of calculating a first filter material length and a second filter material length according to one ore more spectrum function and the raw data of the first phantom as well as the second phantom; the step of adjusting said spectrum function to make the first filter material length and the second filter material length agree with predefined conditions; the step of calculating a beam hardening curve according to the adjusted spectrum function and the first filter material length as well as the second filter material length met with the predefined conditions; and the step of processing the raw data by the calculated beam hardening curve to eliminate beam hardening effects. After calibrating raw data by using the adjusted spectrum curve, image results showed that artifacts such as shading dark artifacts and rings artifacts were significantly reduced.

A color filter including a substrate and a green photoresist is provided. The green photoresist is disposed on the substrate, and the spectrum function thereof has a first peak within a wavelength window between 480 nm and 550 nm. Whereas a transmittance intensity of the spectrum function of green photoresist at wavelength 750 nm is greater than that of 0.5 times of the transmittance intensity of the first peak. An optical touch display device with the color filter is also provided.

The invention provides a wave spectrum and energy spectrum composite type X-ray fluorescence spectrophotometer. The wave spectrum and energy spectrum composite type X-ray fluorescence spectrophotometer comprises an X-ray source, a light filter switching mechanism, a sample moving platform, a sample cup, a diaphragm switching mechanism, a primary collimator switching mechanism, a dispersive crystalswitching mechanism, a secondary collimator switching mechanism, a gasflow type proportional counter, a scintillation counter, an SDD detector, a main control panel and a PC machine. The wave spectrum and energy spectrum composite type X-ray fluorescence spectrophotometer has the following advantages: detection or point/face scanning can be rapidly completed by using an energy spectrum function when the sample is subjected to integrated component analysis and distribution analysis, and the whole body or certain area of the sample can be subjected to element analysis and distribution analysisby a wave spectrum function, so that organic combination of the wave spectrum and energy wave spectrum functions is realized, the two functions can be applied to integrated element component analysisand distribution analysis of the sample, the characteristics of high resolution, rapidness, flexibility and combinability are achieved, the reliability of the analysis result can be improved and the detection efficiency can be improved obviously.

The device for designing dual orthogonal filter (DOF) includes following parts and operations: transmission filter (TF) design device in use for designing TF by using traditional method; FFT device in use to calculate FFT to calculate frequency response; device for selecting target correlation function in use for selecting target cross power spectrum function (TCPSF), and aliasing the function sampled in 1/Ts interval to obtain a constant; device for designing receiving filter carries out dividing TCPSF by frequency response of transmission filter in frequency domain (FD), or equivalent deconvolution operation in time domain (TD); adding window for the result, or equivalent convolution operation of window function in TD; inverse Fourier transforming the signal with window being added to TD, conjugated backout for the signal in TD so as to obtain impulse response in TD of DOF. Dual orthogonal nature between receiving filter and TF guarantees no loss on comm. system.

The invention discloses a method and device for correcting phase errors of an interference spectrum imaging instrument. The method for correcting the phase errors of the interference spectrum imaging instrument includes the steps that IFFT is carried out on small bilateral portions of an interference pattern obtained by the interference spectrum imaging instrument to obtain phase factors, and FFT is carried out on the phase factors to obtain a symmetrization function; convolution processing is carried out on the interference pattern and the symmetrization function to obtain a convolution interference pattern; IFFT is carried out on the convolution interference pattern to obtain a recovery spectrum function, and IFFT is carried out on the small bilateral portions of the convolution interference pattern to obtain phase error factors; the recovery spectrum function is corrected through the phase error factors to obtain a target spectrum function. The interference pattern is firstly corrected in the time domain, then the spectrum function is corrected in the frequency domain, the accuracy of a recovery spectrum is improved, and meanwhile consideration is given to the calculation speed.

The invention provides a modeling method for a multi-scale non-uniform discrete random medium in a lunar soil layer. The modeling method comprises the following steps of: step 1, determining all parameter values of the random medium in the lunar soil layer, and constructing a self-related function; step 2, carrying out Fourier transform on the constructed self-related function and solving a power spectrum density function of a space random disturbing function; step 3, adding a random phase function aiming at the solved power spectrum density function and calculating a random power spectrum function; step 4, carrying out reversed Fourier transform on the calculated power spectrum density function to obtain the space random disturbing function of the random medium; step 5, normalizing the space random disturbing function to obtain a discrete random medium model; and step 6, adding lunar rock particles into the discrete random medium model according to lunar rock sampling sample data and lunar rock particle distribution characteristics in the lunar soil layer so as to establish a multi-scale non-uniform discrete random medium model in the lunar soil layer.