27 results about "Fresnel zone" patented technology

The invention relates to the technical field of seismic exploration, in particular to a seismic offset angle gather generation method and device, equipment and a medium. The method comprises the following steps: acquiring pre-stack seismic data of a work area after preprocessing; performing pre-stack time migration on the pre-stack seismic data, and performing grouping accumulation according to inclination angles in the pre-stack time migration process to generate an inclination angle gather; according to the inclination angle gather, picking up Fresnel zone boundaries of reflection events of all imaging points according to preset intervals; stable-phase offset is carried out by using the picked Fresnel zone boundary, and an offset angle gather of stable-phase control is generated according to grouping accumulation of incident angles in the offset process. The problems that an existing method for generating an angle gather through pre-stack depth migration is difficult in interval velocity modeling and high in calculation cost are solved.

The invention belongs to the technical field of micro-nano processing, and particularly relates to a Pt-HSQ-based high-resolution X-ray Fresnel zone plate and a preparation method thereof. According to the X-ray Fresnel zone plate, a Pt-HSQ metal-inorganic material system is adopted, a diffraction structure with a large aspect ratio and Pt material quasi-periodic dense stripes specially needed by an X-ray zone plate lens is formed through electron beam lithography and an ALD process, and diffraction focusing from a soft X-ray wave band to a hard X-ray wave band and imaging with an amplification function are achieved. The wave zone plate has excellent mechanical stability, and the irradiation resistance and morphology retentivity of the wave zone plate under high-energy irradiation are remarkably improved. And high-resolution X-ray focusing elements with different energy wavebands and different focal lengths can be prepared according to geometric design and material selection of the wave zone plate. The lens is suitable for microscopic imaging, coherent diffraction imaging, X-ray spectrum, nanometer detection and other scenes of a synchrotron radiation or off-line laboratory X-ray light source, and has wide popularization value and application prospect.

The invention discloses a multi-focus composite Fresnel phase diagram rapid generation and power equalization method and system for one-to-many free space laser communication. According to the method, aiming at a scene in which a plurality of user targets are located at different directional angles and different propagation distances, a focusing + directional single-beam phase is constructed for each target on the basis of analyzing a Fresnel zone lens phase and a linear tilt phase, and the phase is taken after complex field superposition is performed according to a preset power weight, so that the target target is obtained. A composite phase diagram for a phase-type spatial light modulator (SLM) is directly obtained. The power weight is preset according to a link budget or a task demand so as to realize on-demand distribution and equalization of multi-beam output power; and meanwhile, fixed phase bias can be introduced to each beam to suppress inter-beam interference fringes. According to the method, frame-by-frame iterative solution is not needed, the calculation complexity is low, and high-frame-rate and low-delay online updating is easy to realize.

The application provides a tracking method and device based on a Fresnel region, electronic equipment and a storage medium, comprising: determining a target moving speed of a passive target based on frequency domain channel estimation information; taking a plurality of grids in an environmental coordinate system as initial positions, and constructing candidate motion trajectories based on the target moving speed at a plurality of observation times; for each candidate motion trajectory, and a PDP observation ratio of the observation time corresponding to each coordinate position in the candidate motion trajectory, determining an energy hot spot trajectory diagram; for each candidate motion trajectory, judging whether the energy hot spot trajectory diagram corresponding to the candidate motion trajectory matches a signal strength hot spot diagram corresponding to the environmental coordinate system, and taking the candidate motion trajectory corresponding to the energy hot spot trajectory diagram matched with the signal strength hot spot diagram as a tracking result of the passive target. The application realizes accurate tracking and positioning of the passive target.

This invention discloses an indoor wireless positioning method based on WiFi and acoustic multimodal combination, comprising the following steps: A user moves freely within the sensing scene; a commercial WiFi device collects the user's CSI (Continuous Sensor Indicator) during movement, extracts the PLCR (Pulse Path Length) from the CSI, calculates the path length of the reflected signal, and constructs a Fresnel zone elliptical model; a microphone array collects the user's footsteps during movement, and the sample offset of different microphone pairs is solved by the peak value of the cross-correlation function of each pair of microphone signals; an angle is calculated based on the sample offset to construct a ray model; the Fresnel elliptical model and the ray model are combined to calculate the error, and the user's positioning and tracking are completed through maximum likelihood optimal estimation. Compared with traditional WiFi positioning methods, this invention eliminates the additional phase calibration cost and improves tracking accuracy; compared with traditional acoustic tracking systems, tracking is possible even if the user does not actively issue voice commands, achieving true passive tracking.

The present invention is a Fresnel zone plate lens which improves radio wave reception sensitivity by suppressing the radio wave shielding action of a conductive film while reducing an installation space, and said Fresnel zone plate lens has a base 10, transmission sections T which are formed in a conductive film 20 on the base 10 and allow radio waves to pass therethrough, and shielding sections S which are formed in the conductive film 20 on the base 10 and have a lower degree of radio wave transmittance than the transmission sections T. The transmission sections T and the shielding sections S are disposed alternatingly in concentric circles form a Fresnel zone plate lens (FZPL) 2 that focuses, on a focal point, radio waves having a first wavelength λ1. The transmission sections T have a frequency selective surface (FSS) structure which allows radio waves having the first wavelength λ1 to pass therethrough.

This application provides a method, apparatus, device, and computer-readable storage medium for determining the extension length of an observation line in seismic exploration. The method includes: acquiring layer information of a target layer; the layer information including depth, velocity, maximum dip angle, and the dominant frequency of the target layer's location; determining the offset aperture for the target layer to meet the first Fresnel zone requirement based on the velocity and the dominant frequency; determining the offset aperture for the target layer to meet the 30-degree diffraction repositioning requirement based on the depth; determining the offset aperture for the target layer to meet the stratigraphic dip angle requirement based on the depth and the maximum dip angle; and determining the extension length of the observation line based on each offset aperture. The observation line extension length determined by this method can meet the offset repositioning imaging requirements of all reflection points, improving the acquisition accuracy of the observation system.

The application discloses a fluid antenna source positioning method and device based on aperture dynamic reconfiguration, and relates to the technical field of wireless communication and array signal processing. The application is proposed to solve the problems of limited positioning accuracy and insufficient environmental adaptability caused by fixed array structure and single source field model. The steps are as follows: S1. Constructing a fluid antenna system S-FAS with adaptive aperture adjustment capability, and establishing a unified modeling framework based on accurate spatial geometry ESG; S2. Switching between compressed and expanded apertures according to task requirements, collecting observation data and generating statistics; S3. Estimating the direction under the compressed aperture and suppressing mutual coupling and amplitude and phase errors; S4. Jointly estimating the target direction and distance under the expanded aperture with the initial value as the anchor point to realize high-precision positioning. The application can work stably in a near-field, Fresnel zone and far-field multi-source mixed environment without distinguishing source types or isolating signals, has high precision, low complexity and strong adaptability, and is suitable for intelligent sensing and low-altitude communication scenes.

The application belongs to the technical field of structured light, and relates to a structured light three-dimensional reconstruction system and method based on a fold-diffraction hybrid imaging. The system comprises a structured light projection module, a fold-diffraction hybrid imaging module, a target object and a data processing module. The structured light projection module, the fold-diffraction hybrid imaging module and the target object are arranged at intervals. The structured light projection module is connected with the data processing module to emit structured light and produce diffuse reflection on the surface of the target object. The fold-diffraction hybrid imaging module comprises filter plates, Fresnel zone plates, liquid lenses, solid lenses and near-infrared cameras arranged at intervals. The filter plates receive the diffuse reflected light and transmit the light to the near-infrared cameras in turn. The liquid lenses are connected with the data processing module to switch the structured light detection mode by controlling the input voltage of the liquid lenses. The data processing module is connected with the near-infrared cameras to collect multi-line structured light images and realize three-dimensional reconstruction. The application can switch the structured light detection mode.

The invention discloses a fluid antenna source positioning method and device based on aperture dynamic reconfiguration, and relates to the technical field of wireless communication and array signal processing. The scheme is provided for solving the problems of limited positioning precision and insufficient environmental adaptability caused by a fixed array structure and a single source field model. The method comprises the following steps: S1, constructing a fluid antenna system S-FAS with adaptive aperture adjustment capability, and establishing a unified modeling framework based on precise space geometry ESG; s2, switching between aperture compression and aperture expansion according to task requirements, collecting observation data and generating statistics; s3, direction initial estimation is carried out under the compressed aperture, and mutual coupling and amplitude-phase errors are suppressed; and S4, performing joint estimation on the target direction and distance by taking the initial value as an anchor point under the expanded aperture to realize high-precision positioning. The method does not need source type distinguishing or signal isolation, can stably work in near-field, Fresnel region and far-field multi-source mixed environments, has high precision, low complexity and strong adaptability, and is suitable for scenes such as intelligent sensing and low-altitude communication.

This invention discloses a fast autofocusing method for layered imaging based on vortex edge enhancement and selective linear fitting, comprising: acquiring the initial complex amplitude of an object; propagating the initial complex amplitude to a virtual Fresnel zone plate, modulating it to generate a hologram, extracting edge information during the backpropagation of the hologram, locating the region of interest (ROI), and calculating the sharpness bias within this ROI, storing it along with the corresponding axial distance in a historical dataset; during iterative iteration, substituting the updated distance parameters for each iteration of the layered imaging algorithm, classifying all data points in the historical dataset into linear or saturated intervals, performing least-squares fitting on data points classified as linear intervals, outputting the intercept and slope of the fitting function, and calculating new axial distances based on the current data point classification using different strategies, before proceeding to the next iteration. This invention enables high-precision and high-efficiency automatic calibration in a single preprocessing step.

This invention discloses a depth measurement and edge extraction method based on a single all-dielectric metasurface, belonging to the fields of micro-nano optics and image information extraction applications. The phase distribution of the all-dielectric metasurface is obtained using the Fresnel zone method. Each Fresnel region corresponds to a spiral phase with a different topological charge number, increasing sequentially from the inside out, generating a double-helix point spread function. The metasurface is placed on the spectral plane of a 4f system, with a pair of linear polarizers and a quarter-wave plate placed before and after it respectively, achieving corresponding circular polarization selection and ensuring phase modulation based on the geometric phase modulation principle, thus obtaining the designed metasurface optical system for depth measurement and edge extraction. When incoherent light is incident, the main lobe rotation angle of the double-helix point spread function corresponding to the "twin image" is extracted using image cepstral analysis, thus deducing the object's depth information. When coherent light is incident, the incident light interacts with the central part of the metasurface. Through the convolution of the target object with the spiral phase, coherent destructive phase can be achieved for regions with uniform phase / amplitude, extracting the edge information of the target object. This invention enables both depth measurement and edge extraction.

The present application relates to a kind of signal dynamic shielding error reduction method and system.This method constructs the ranging model about the projection of Fresnel zone to two-dimensional plane according to the UWB device of Anc and Tag, and the wearer Wearer of label Tag;The blocking degree index DFO of Wearer is calculated by ranging model, and ranging model is optimized using DFO to reduce shielding error;In the optimized ranging model, when Wearer is in the Fresnel zone ellipse, the actual blocking length of Wearer to the Fresnel zone ellipse is calculated;The range of truncated relative heading angle RHA is calculated in combination with blocking length.The present application establishes mathematical model by projecting the UWB device of Tag and Anc, wearer and Fresnel zone to two-dimensional plane, and is optimized in combination with index DFO, effectively reduces the error in positioning process.

The purpose of the present invention is to provide a diffractive optical element having improved shape stability.　This diffractive optical element causes diffraction with respect to incident light, and comprises a substrate that transmits the incident light, a fine structure that is composed of a curable resin composition and forms an unevenness on a first main surface side of the substrate to form a diffraction pattern for diffracting the incident light, and a first protective layer that is transmissive to the incident light and covers the fine structure, the fine structure exhibiting any of a Fresnel zone plate shape, a linear zone plate shape, a fractal zone plate shape, and a photon sieve plate shape when viewed in a direction orthogonal to the first main surface.

The application provides a two-dimensional curved wide-line dip-angle domain stable-phase pre-stack time migration method, device and equipment, and relates to the technical field of seismic exploration data processing. The method comprises the following steps: obtaining original two-dimensional curved wide-line seismic data; determining common midpoint distribution and migration velocity field according to the original two-dimensional curved wide-line seismic data. For each common midpoint, the tangential azimuth of the common midpoint is calculated according to the common midpoint distribution and the migration velocity field, and a dip-angle gather distributed along the tangential azimuth is constructed. According to the dip-angle gather, the corresponding dip-angle domain Fresnel zone at each imaging point is determined. According to the dip-angle domain Fresnel zone, two-dimensional curved wide-line dip-angle domain stable-phase pre-stack time migration is performed, migration results under different migration distances are generated, and the migration results are stacked to generate a migration profile. The method is used to achieve the effect of effectively balancing imaging integrity and signal-to-noise ratio when pre-stack time migration processing of two-dimensional curved line data is performed.

The present application relates to a kind of high-efficiency solid-state magnetometer of exciting NV color center and its preparation method, belong to the preparation technical field of solid-state magnetometer.The solid-state magnetometer of the present application replaces traditional objective with adjustable focus fresnel zone plate S1, to realize the collimation focusing of excitation laser, its focal length can be adjusted by electric control;At the same time, superstructure S3 is made on the surface of diamond with NV color center, to realize the further concentration of microwave energy;In addition, by M / NEMS method, bevel is formed on the sidewall of diamond, and is plated with composite film structure, while realizing high reflection of fluorescence, the high reflection film is effectively protected.Therefore, the NV color center in the high-efficiency solid-state magnetometer of exciting NV color center of the present application is under the dual action of laser and magnetic field, realizes the microstructure of high-efficiency excitation, collection of fluorescence, to overcome the problems of current NV color center magnetometer, such as large volume, low integration level and low efficiency.

The application discloses a driver physiological feature detection system, which comprises a WiFi module, a directional receiving antenna unit, a signal processing unit and an analysis unit. The positional relationship between the directional receiving antenna unit and the WiFi module and the chest cavity position of the driver satisfies the Fresnel zone spatial geometric constraint. The directional receiving antenna unit is used for collecting and adjusting the receiving direction according to the signal quality of the WiFi-CSI signal reflected by the chest cavity of the driver, so that the directional receiving antenna unit is aligned with the chest cavity position. The signal processing unit is used for preprocessing the WiFi-CSI signal and generating a target segmented sequence. The analysis unit is used for inputting the target segmented sequence into a neural network and outputting physiological feature information through the neural network. In this way, the application pre-plans the antenna position, dynamically aligns the chest cavity with the adjustable directional antenna, collects and preprocesses the WiFi-CSI signal, extracts the physiological feature, and improves the detection accuracy and stability. The application is suitable for vehicles with intelligent driving function or intelligent cabin configuration.

Provided is a diffractive optical element which can separate incident light for each wavelength, focus the light of each wavelength to different positions, and be manufactured relatively easily.　The present invention includes: a substrate which transmits light; and a plurality of diffraction patterns including a first diffraction pattern and a second diffraction pattern which are formed so as to have different center positions on the same main surface of the substrate. Each of the first diffraction pattern and the second diffraction pattern exhibits a pattern shape selected from the group consisting of a Fresnel zone plate pattern, a fractal zone plate pattern, and a photon sieve plate pattern.

The invention provides an inclination angle domain stationary phase pre-stack time migration method, device and equipment of a two-dimensional bending width line, and relates to the technical field of seismic exploration data processing. The method comprises the following steps: acquiring original two-dimensional bending width line seismic data; according to the original two-dimensional curved wide line seismic data, common midpoint distribution and a migration velocity field are determined. And for each common center point, calculating a tangential azimuth angle of the common center point according to the distribution of the common center point and the migration velocity field, and constructing an inclination angle gather distributed along the tangential azimuth angle. And according to the inclination angle gather, determining an inclination angle domain Fresnel zone corresponding to each imaging point. And according to the inclination angle domain Fresnel zone, executing two-dimensional bending width line inclination angle domain stationary phase pre-stack time migration, generating migration results under different offset distances, and superposing the migration results to generate a migration profile. The method is used for achieving the effect of effectively balancing the imaging integrity and the signal-to-noise ratio during the pre-stack time migration processing of the two-dimensional curved line data.

The application discloses a double-sided achromatic superlens based on phase load balancing and a design method, and belongs to the technical field of micro-nano optics and computational imaging. The superlens comprises a transparent low-refractive substrate, a first structure layer located on the incident surface of the substrate and a second structure layer located on the emitting surface of the substrate; the first structure layer is a non-periodic phase type Fresnel zone plate, which is used for providing a basic focusing phase and pre-bending incident parallel light to the inside of the substrate; the second structure layer is an isotropic cylindrical nano column arranged in a square lattice, which is used for providing a residual focusing phase and a wide-band chromatic aberration compensation phase. Through the double-sided phase distribution balancing logic, the light deflection pressure is shared together, combined with the full-path scalar diffraction model, super-atom response calculation and end-to-end deep learning optimization, the bottleneck of low-refractive material in high-NA achromatic application is completely solved, and the micro-nano processing technology of large area and low cost is compatible.

The invention discloses a Wi-Fi-based electromagnetic wave and Fresnel zone visualization teaching experiment system, and the system comprises a simulation platform which is used for carrying out the simulation calculation according to preset electromagnetic wave propagation parameters, and generating a visual graph which comprises an electromagnetic wave waveform, interference fringes and / or Fresnel zone distribution; the simulation platform is used for simulating electromagnetic waves, the experiment platform is used for carrying out an electromagnetic wave propagation experiment in a physical space, and the control and display unit is in communication connection with the simulation platform and the experiment platform; wherein the control and display unit is configured to obtain real-time position information of the transmitting end, the receiving end and the reflecting end in the experiment platform, and send the position information and experiment parameters to the simulation platform; and receiving and synchronously displaying the visual graph generated by the simulation platform and the actually measured signal data acquired by the experiment platform. Simulation and experiments can be integrated, visualization of the electromagnetic wave phenomenon is achieved, and teaching is facilitated.

The invention discloses a multi-circular-ring collimation optical fiber array and system for generating Bessel-like non-diffraction light beams and a parameter design method of the multi-circular-ring collimation optical fiber array, and the multi-circular-ring collimation optical fiber array can be manufactured by matching an optical fiber array with a micro-lens array for collimation according to a non-diffraction distance range or a requirement on the size of a corresponding collimated light beam for a relatively short non-diffraction distance; for a relatively long distance, the optical fiber collimator array can be formed by packaging an independent optical fiber collimator array; the optical fiber laser array output by the multi-ring collimation optical fiber array is coherently combined in a near field, namely a Fresnel area to generate a non-diffraction light field; the invention further provides a system and a method based on the multi-circular-ring collimation optical fiber array. According to the method, Bessel-like (0-order) non-diffraction beams can be generated in a Fresnel region (near-field region), the problem of high calculation complexity caused by multi-parameter simultaneous parallel optimization design is solved, and the design efficiency is improved.

This invention discloses an optical hydrophone structure based on Fresnel zone plate sensitization, belonging to the field of underwater acoustic signal detection technology. It includes a single-mode optical fiber, an elastic cylinder, a Fresnel zone plate, and a metal cavity. The single-mode optical fiber is uniformly and tightly wound around the elastic cylinder, which is located inside the metal cavity. One end of the metal cavity has an acoustic wave incident aperture. The Fresnel zone plate is fixed at the acoustic wave incident aperture of the metal cavity and has several concentric acoustic transmission rings and blocking rings. This invention employs the above-mentioned optical hydrophone structure based on Fresnel zone plate sensitization, which is simple in structure, has few components, and low cost. It possesses good water pressure resistance and electromagnetic interference resistance, making it suitable for complex underwater environments such as marine acoustic exploration and underwater weak target monitoring.

The invention relates to the technical field of oil field oil production engineering, in particular to a migration method for improving the seismic resolution of a thin reservoir. The problem that absorption attenuation of seismic waves in the propagation process cannot be effectively solved through an existing method is mainly solved. Comprising the following steps: S1, obtaining three-dimensional pre-stack seismic data after pre-stack processing; s2, establishing a three-dimensional equivalent Q field; s3, the optimal offset aperture is solved in a stable phase mode; and S4, inputting upper bound and lower bound parameters of a Fresnel zone and the equivalent Q field generated in the step S2 into the viscoelastic medium pre-stack time migration in a form of a migration aperture field to realize the stable-phase pre-stack time migration of the viscoelastic medium. According to the migration method for improving the seismic resolution of the thin reservoir, the medium viscosity and the absorption attenuation effect of the thin interbed structure on seismic waves in the seismic wave propagation process are considered, and the requirements for high-fidelity and high-resolution imaging and fine oil-gas exploration effect and efficiency can be met.

This invention provides a method for fabricating a flat plate objective and the flat plate objective itself. The fabrication method includes: acquiring the property information of a Fresnel zone plate; calculating the diffraction field of each zone within a target region based on the zone radius; searching for an optimized phase using an optimization algorithm, and obtaining the phase factor of each zone based on the optimized phase; multiplying the phase factor by the complex amplitude of the light field of each zone within the target region, and then coherently superimposing them to obtain the total complex amplitude of the diffraction field at the target region; obtaining the total diffraction field intensity through the total complex amplitude of the diffraction field, calculating the root mean square error (RMSE) of the total diffraction field intensity and the target intensity, and obtaining the RMSE; determining the total diffraction field as the target total diffraction field when the RMSE characterization of the total diffraction field meets preset conditions; superimposing the optimized phase that achieves the target total diffraction field with the phase of the Fresnel zone plate to obtain the phase of the flat plate objective, and fabricating the target flat plate objective based on the phase of the flat plate objective.

The invention relates to the technical field of wireless communication, in particular to an optimized low-altitude condition radio wave propagation prediction method and device and a storage medium, and the method comprises the steps: firstly constructing a three-dimensional collaborative database fusing high-resolution terrain elevation, atmospheric profile and earth surface material information; based on a three-dimensional graphic obstacle recognition algorithm, a low-altitude propagation loss model or a ground propagation model is adaptively selected as a dominant prediction model by analyzing the shielding proportion of an obstacle on a propagation path to a first Fresnel region. And if the low-altitude model is selected, intelligently matching the corresponding diffraction loss sub-model according to the topographic features, and calculating the topographic diffraction loss. Meanwhile, the atmospheric attenuation loss is calculated in a layered manner, and the earth surface reflection loss is calculated by combining earth surface material information. And finally, carrying out superposition calculation. According to the invention, through multi-source data fusion, propagation mechanism intelligent discrimination and multi-physical effect cooperative calculation, the precision and adaptive ability of radio wave propagation prediction in a low-altitude complex environment are significantly improved.

A lensless imaging method for combined generation of a twin image and an original image comprises two parts of prior learning of a high-dimensional combined solution space and combined generation of the twin image and the original image, and in the prior learning stage of the high-dimensional combined solution space, a twin image domain scoring network and an original image domain scoring network are trained respectively, and a high-dimensional combined solution space is obtained; wherein the twin image domain scoring network specially learns artifact distribution characteristics formed by diffraction effect and conjugate wave interference, and the original image domain scoring network focuses on intrinsic structure characteristics of a modeling target object; by constructing a high-dimensional joint solution space formed by an original image and a twin image, an artifact removal problem in traditional Fresnel zone plate lens-free imaging is converted into an independent generation problem of the original image and the twin image, so that mutual interference in an iterative optimization process is effectively avoided.