98 results about "Domain imaging" patented technology

A method and an apparatus for noninvasively and quantitatively determining spatially resolved absorption and reduced scattering coefficients over a wide field-of-view of a food object, including fruit or produce, uses spatial-frequency-domain imaging (SFDI). A single modulated imaging platform is employed. It includes a broadband light source, a digital micromirror optically coupled to the light source to control a modulated light pattern directed onto the food object at a plurality of selected spatial frequencies, a multispectral camera for taking a spectral image of a reflected modulated light pattern from the food object, a spectrally variable filter optically coupled between the food object and the multispectral camera to select a discrete number of wavelengths for image capture, and a computer coupled to the digital micromirror, camera and variable filter to enable acquisition of the reflected modulated light pattern at the selected spatial frequencies.

The invention relates to methods and computer-readable medium to implement computing the propagation velocity of seismic waves in the earth. The invention computes the true propagation velocity of seismic waves in the earth, which is a condition of obtaining an accurate image of subsurface geology that can be used to prospect for oil and gas deposits. In an embodiment, the method of computing the propagation velocity of seismic waves in earth, includes providing an estimate of the propagation velocity, generating a time shift gather using a depth migration at a plurality of locations of the earth, converting each of the time shift gathers to a semblance gather, transforming each semblance gather into a velocity gather whose energy peaks represent a root-mean-square average of the propagation velocity along the forward and backward path between earth's surface and a point of the subsurface geology, and converting the energy peaks to the propagation velocity.

A migration method using hybrid one-way and full-way (HOF) wave equation propagation. The HOF method extrapolates seismic wavefields in less complex media with a one-way wave equation propagator and extrapolates seismic wavefields in extremely complex media with a full-way wave equation propagator. For prestack depth migration, the HOF extrapolates source-side and receiver-side wavefields independently. Frequency-space domain and time-space domain imaging conditions are applied to the one-way and the full-way extrapolated wavefields, respectively. A suitable amplitude matching factor is introduced to combine the one-way and full-way images. The HOF method is a cost-effective migration that produces superior image quality with less noises and less computational resources.

The invention relates to an azimuth fidelity angle domain imaging data processing method aiming at fractured oil and gas reservoir seismic exploration. The azimuth fidelity angle domain imaging data processing method comprises the following steps of: (1) simulating three-dimensional seism of ground, acquiring a seismic wave signal by a data acquisition device, and preprocessing according to an amplitude relative fidelity processing flow; (2) determining, by input equipment, a local target and an imaging range thereof according to a geological task, halving azimuth imaging arrays and initializing azimuth/angle domain imaging arrays; and (3) gradually inputting seismic wave data preprocessed in the step (1) into a processor by the data acquisition device, determining a maximum imaging range corresponding to the seismic wave by the processor according to the position of a central point and migration aperture limitation, and the like. Compared with the prior art, the azimuth fidelity angle domain imaging data processing method has the advantages of high-accuracy imaging and description of a complex geologic body, capability of producing a high-fidelity multi-azimuth imaging data body and an azimuth common imaging point gather by fractured reservoir-oriented azimuth anisotropic analysis and parameter extraction, and the like.

The invention belongs to the technical field of ferroelectric or piezoelectric material electric domain testing, and relates to a double-frequency multichannel synchronization detection method for achieving electric domain imaging through an inverse piezoelectric effect. The method employs two phase locking amplifiers to achieve the real-time synchronous detection of out-plane and in-plane piezoelectric signals of a to-be-tested sample. Reference signals of the two phase locking amplifiers are provided by two independent frequency sources, and the frequency sources also provide AC signals which are the same as the reference signals, wherein the AC signals serve as excitation signals. The excitation signals provided by the two frequency sources are superposed through an adder and then serve as AC excitation signals located between a conductive probe and the to-be-tested sample. The method can detect the amplitude and phase signals of the out-plane and in-plane piezoelectric vibration of the to-be-tested sample through one-time scanning, achieves multichannel synchronous output in a real-time mode, and greatly improves the detection efficiency. Meanwhile, the method can improve the resolution of electric domain imaging, and effectively improves the detection accuracy.

The invention relates to an earthquake multiple migration method. According to the invention, the improvement is carried out on the basis of a reverse time migration method and multiples are fused into the reverse time migration process, so that the multiples are homed to a correct position under the ground. The multiple migration method disclosed by the invention is mainly divided into the following two steps of: a first step of obtaining the multiples by utilizing known methods for forecasting the multiples; and a second step of carrying out pre-salt depth domain imaging by utilizing the reverse time migration method. According to the invention, multiple information is utilized; the multiples are fused into the reverse time migration process; earthquake record wave fields of primaries and the multiples are utilized to carry out imaging. Compared with the prior art, the method disclosed by the invention has the advantages that the multiple pre-salt imaging can be implemented; the underground illumination level which has a larger range and is more balanced is achieved; and the resolution ratio of the pre-salt imaging is greatly improved. The earthquake multiple migration method can be widely used in the field of oil-gas exploration and particularly has a more obvious effect on the imaging of a pre-salt structure.

The invention discloses a method and an apparatus for determining a poynting vector of a seismic wave field and a computer storage medium. The method comprises the following steps: establishing an underground shot point forward-propagation wave field and a detection point back-propagation wave field; determining a medium type of the forward-propagation wave field and the back-propagation wave field; when the media are isotropic media, performing vertical-horizontal wave field separation on the forward-propagation wave field and the back-propagation wave field according to a preset equation decoupling algorithm, and when the media are heterogeneous anisotropic media, performing longitudinal-horizontal wave field separation on the forward-propagation wave field and/or back-propagation wave field according to a preset variation function IDW interpolation algorithm; decomposing a separated longitudinal-wave wave field and/or a transverse-wave wave field in a top direction, a bottom direction, a left direction and a right direction, and obtaining multiple directional-wave wave fields; and selecting multiple directional-wave wave fields from the multiple directional-wave wave fields, and calculating the poynting vector of the multiple directional-wave wave fields. By adopting the method, the poynting vector of each decomposed directional wave field can be calculated, so that more accurate angle-domain imaging gather can be obtained, and the imaging quality can be improved.

Embodiments of the invention provide a system and method for converting coordinate systems for representing image data such as for example seismic data, including accepting a first set of seismic data, mapping the first set of seismic data to a second set of seismic data, where the dimensionality of the second set of seismic data is less than the dimensionality of the first set of seismic data, and generating image data by processing the second set of seismic data.

The invention relates to a Legendre-orthogonal-decomposition-baesd curve motion trajectory SAR wave-number domain imaging method. The method comprises: constructing a slant range history expression ina curved motion trajectory mode by using a three-dimensional speed and a three-dimensional acceleration; carrying out polynomial expansion on the constructed slant range history expression and carrying out keeping to the fourth order; transforming an SAR echo signal corresponding to the slant range into a two-dimensional frequency domain to obtain a two-dimensional frequency spectrum; with a Legendre orthogonal polynomial, spreading the two-dimensional frequency spectrum for a distance range frequency and carrying out keeping to a third order; carrying out phase compensation based on a two-dimensional frequency spectrum developed based on Legendre and completing distance migration correction and distance range focusing; and carrying out azimuth compression in a distance-Doppler domain andcarrying out transformation in a two-dimensional time domain to obtain a focusing image. Therefore, a target imaging blurring problem at the scene edge is solved.

The invention relates to a travel-time table and angle table acquisition method for anisotropic medium angle domain Kirchhoff prestack depth migration and an imaging method thereof. The acquisition method comprises steps: according to an anisotropic medium acoustic wave equation, an eikonal equation in the anisotropic medium is deduced, ray equations for anisotropic medium acoustic approximation are deduced and solved through the eikonal equation, ray paths, travel time and propagation direction information under the anisotropic medium acoustic approximation meaning are thus acquired, Angle domain ray tracing is carried out, and a travel-time table and an emergence angle table are built. The method of the invention has the advantages that the ray equations for the anisotropic medium can be approximatively deduced based on an acoustic law; the reliable travel-time table and the reliable angle table can be provided for Kirchhoff prestack depth migration; and thus, angle domain imaging can be realized accurately.

The invention relates to a frequency domain imaging method of an ultrasonic scanning microscope, being applicable to the field of ultrasonic scanning microscope detection and ultrasonic C-scanning detection and capable of improving the C-scanning imaging precision in ultrasonic micro-scanning and revealing details which are difficultly discovered in time-domain imaging. The frequency domain imaging method comprises the following steps of: firstly, carrying out full-wave acquisition on an A-scanning signal generated in the C-scanning process; secondly, carrying out fast Fourier transform on signals in data gates of each A-scanning waveform, finding out the maximum amplitudes in the signals, normalizing the maximum amplitudes and expressing the intensities by using corresponding color gray levels; and finally, drawing pixel points on a screen so as to accomplish the frequency domain imaging in ultrasonic micro-scanning.

The invention discloses a subaperture wave number domain imaging method for a squint sliding spotlight SAR (Synthetic Aperture Radar). A traditional sliding spotlight SAR subaperture method is improved aiming at squint conditions. The subaperture wave number domain imaging method comprises the following steps: firstly, overlapping a whole aperture and dividing subapertures; taking an extended wave number domain method used for the squint conditions as a subaperture basic imaging method; and finishing azimuth processing in a distance Doppler domain by adopting an improved BAS method to splice the subapertures, so as to obtain a whole aperture image under the squint conditions. With the adoption of the subaperture wave number domain imaging method, the problems of the squint sliding spotlight SAR of large data size, non-zero azimuth Doppler center and oversized Doppler bandwidth are solved, and the practical value is larger.

The invention discloses a PFM-based lithium niobate nano-domain processing and imaging method. The method comprises the following steps: firstly, scanning the surface of a lithium niobate film by utilizing a conducting probe for applying first alternating current voltage; secondly, performing nano-domain processing on the scanned lithium niobate film by utilizing a conducting probe for applying first direct current voltage; and finally, performing nano-domain structure imaging on the lithium niobate film after domain processing by utilizing a conducting probe for applying second alternating current voltage, and simultaneously, applying second direct current voltage to the surface of the lithium niobate film. The method disclosed by the invention has the effects that before lithium niobatenano-domain processing, the alternating current is applied, and then the forming probability of the lithium niobate nano-domain can be improved, thereby increasing the capacity of a lithium niobate nano-ferroelectric memory; and during lithium niobate nano-domain imaging, the direct current is applied, and then the structure imaging resolution of the lithium niobate nano-domain can be obviously improved, thereby verifying whether the lithium niobate nano-domain is formed by reversion or not, and determining the size of the nano-domain.

Method and apparatus for separating seismic diffracted waves, in seismic exploration field. The method comprises acquiring seismic shot gather data carrying underground geological information in preset geological region; inputting preprocessed single-shot data obtained by preprocessing seismic shot gather data and a preset migration velocity model to three-dimensional single-shot angle domain imaging formula and performing wave field back-propagation processing on the seismic shot gather data to obtain information of azimuth, emergence angle and amplitude of propagation rays, according to which three-dimensional angle domain imaging matrix is generated, the obtained information corresponding one by one to underground imaging points in the preset geological region; separating low-rank matrix component from the three-dimensional angle domain imaging matrix and determining the low-rank matrix component as the seismic diffracted wave through a preset three-dimensional diffracted wave separating model, improving amplitude integrity and waveform consistency of separated diffracted waves and imaging resolution of geological structures.

The invention discloses a method and a device for nondestructively detecting the optical characteristic parameters of an agricultural product. The method comprises the following steps: carrying out spatial frequency domain imaging to obtain the optical characteristic parameter information initial values of a measured sample, carrying out phase measurement profilometry to obtain the surface height information of the measured sample, correcting the optical characteristic parameter information initial values of the measured sample by using the surface height information of a standard reflecting plate to obtain the corrected optical characteristic parameters of the measured sample, replacing the measured sample with a semispherical solid phantom, repeating above steps, carrying out calculation to obtain optical characteristic parameter fitting coefficients, and carrying out calculation to obtain the final optical characteristic parameter values of the measured sample agricultural product. The device comprises a projecting part, an imaging part and a sample table part, and the projecting part is formed by a projector, a neutral density sheet, two polaroid sheets, an electric translation stage, an optical filter and a CCD camera. The method and the device realize the nondestructive detection of the optical characteristic parameters of the agricultural product, and have the advantages of large imaging range, high precision, low cost and simplicity in operation.

The invention relates to an angle domain pre-stack offset data processing method aiming to detect the oil-gas-bearing property of a reservoir. The method comprises the following steps: 1, a ground earthquake is simulated, and an earthquake wave signal is acquired by a data collector and is subjected to pretreatment through an relative-fidelity amplitude processing process; 2, a local target imaging range is selected according to reservoir projection requirements by input equipment, and an angle domain imaging array is subjected to initialization; and 3, the earthquake wave data subjected to the pretreatment in the step 1 is gradually input into a processor through the data collector, and the largest imaging range corresponding to an earthquake wave is determined through the processor according to a center spot position and migration aperture confinement, so as to judge whether the largest imaging range is in the selected local target imaging range or not, if yes, a step 4 is performed, otherwise, the next earthquake wave is input. Compared with the prior art, the invention has the advantages that the local angle domain pre-stack time offset imaging is realized based on the local direction characteristics of the earthquake wave; and Hi-Fi incident angle domain common imaging point gathers can be directly obtained in the offset process.

The invention discloses a high squint SAR curvilinear path wavenumber domain imaging method based on a slope distance model, comprising: building a high squint SAR (Synthetic Aperture Radar) geometric model on a curvilinear path, selecting any point target Q, successively calculating an instantaneous slant distance R (ta) from an SAR aircraft to the point target Q, and a hyperbola instantaneous slant distance Re(ta) from the SAR aircraft to the point target Q, furthermore calculating the instantaneous slant distance R (X) from a high squint SAR aircraft on a curvilinear path to a point target, calculating distance frequency domain orientation time domain echo signals S (Kr, X) of a high squint SAR on a curvilinear path, furthermore successively calculating orientation time domain echo signals S<^> (Kr, X) of a high squint SAR on a curvilinear path after distance pulse pressure, and orientation time domain echo signals S (Kr, Kx) of a high squint SAR on a curvilinear path after fast fourier transform (FFT), setting an orientation resampling coefficient Kx-new, calculating orientation time domain echo signals S (Kr, Kx-new) of a high squint SAR on a curvilinear path after orientation resampling, furthermore calculating echo signals of a high squint SAR on a curvilinear path under a two-dimensional beam spectrum, successively performing range direction IFFT and azimuth IFFT, and obtaining high squint SAR imaging under a slope distance model.

The invention provides a terahertz time-domain spectroscopy target three-dimensional scattering imaging measurement method. The method is mainly based on an ISAR turntable imaging principle, a targetthree-dimensional scattering imaging test is carried out by utilizing terahertz time-domain spectroscopy scattering information of a two-dimensional rotating target, time-domain amplitude-phase signals of the target at different azimuth angles and pitch angles are obtained, and a target scattering three-dimensional image is obtained through frequency-domain imaging data screening and a THz image reconstruction data processing algorithm. The terahertz time-domain spectroscopy target three-dimensional scattering imaging measurement method provided by the invention is different from conventionalterahertz time-domain spectroscopy point scanning imaging, the terahertz time-domain spectroscopy emission wave beam fully irradiates the target, and the dimension of the test target can reach 10cm and is larger than that of a conventional sample of 1cm-2cm. Terahertz time domain pulse signals reflected by a target are tested through the measuring method, multispectral imaging information and a high-resolution three-dimensional scattering center of the target are obtained, and the target characteristic research and recognition problems are solved.

The embodiment of the application provides a method and apparatus for determining a depth-domain seismic wavelet. The method comprises: obtaining acoustic logging data and determining a depth-domain reflection coefficient sequence and depth-domain imaging data of a well position according to the acoustic logging data; and on the basis of the depth-domain reflection coefficient sequence and depth-domain imaging data of the well position, determining a depth-domain seismic wavelet. According to the method provided by the invention, a matrix equation is constructed based on the depth-domain reflection coefficient sequence and depth-domain imaging data to calculate a depth-domain-reflection-coefficient-sequence-based optimal matching operator using the depth-domain imaging data as an expected output, thereby obtaining the depth-domain seismic wavelet. Therefore, technical problems that the depth-domain seismic wavelet can not be calculated directly, the determination process is complicated, and the accuracy of the determined depth-domain seismic wavelet is poor according to the existing depth-domain seismic wavelet determination method can be solved; and thus a technical effect of determining the depth-domain seismic wavelet accurately and simply is realized.

The invention provides a synthetic aperture laser imaging radar bi-dimensional convolution imaging method. The imaging method is characterized in that quadratic term phase factors are added to pluralized synthetic aperture laser imaging radar target echo signals in the cross rail direction, then focus imaging of the cross rail direction and the clockwise rail direction is achieved while bi-dimensional convolution is carried out, and the imaging result intensity signals are output and displayed. As convolution is adopted for carrying out focus imaging of the cross rail direction and the clockwise rail direction, the requirement for the performance of a computer from the imaging process can be lowered. In addition, space domain imaging results are directly obtained through bi-dimensional convolution, bi-dimensional frequency domain and space domain conversion is not needed, outputting and displaying are carried out directly, imaging procedures are reduced, and the imaging method is the important technology improvement of the synthetic aperture laser imaging radar echo signal imaging process.