191 results about "Em scattering" patented technology

A backlit light display comprises a light guide panel, a prismatic film, an asymmetric top diffuser and an LCD. A linear light source is disposed along a side face of the light guide panel. Light from the linear light source is transmitted though the light guide panel where it is spread and uniformly output through a front face to the prismatic film. Light incident on the prismatic film is redirected more along a first direction than along a second direction. This light is directed more normal to the LCD. An asymmetric diffuser is applied between the prismatic film and the LCD panel to smear the periodic information from the prismatic film and eliminate the Moiré fringe pattern resulting from interference between the periodic structure of the prismatic film and the periodic arrangement of pixels in the LCD. The asymmetric diffuser is aligned with respect to the prismatic film such that it scatters and spreads light more in a second direction than the first direction.

A passive wireless sensor is disclosed. The sensor has at least a measurand sensitive member and an electromagnetically resonant member positioned proximate to each other. The resonant member comprises a preselected resonance frequency, such that it scatters at least a portion of an interrogating signal as a scattered signal proximate to its resonance frequency, and the measurand sensitive member alters the scattered signal as a function of the measurand to change the shape of the scattered signal. The reactive field of the sensor is kept within the sensor to minimize environment interference and to maximize its signal strength. Almost bond-free packaging mitigates problems with delamination or internal stresses due to differing coefficients of thermal expansion.

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

An x-ray CT system for x-ray phase contrast and/or x-ray dark field imaging has a grating interferometer that has a first grating structure that has a number of band-shaped x-ray emission maxima and minima arranged in parallel, the maxima and minima exhibiting a first grating period, a second band-shaped grating structure that produces, as a phase grating, a partial phase offset of x-ray radiation passing therethrough and that exhibits a second grating period, a third band-shaped grating structure with a third grating period with which relative phase shifts of adjacent x-rays and/or their scatter components are detected, and a device for value-based determination of the phase between adjacent x-rays and/or for value-based determination of the spatial intensity curve per detector element perpendicular to the bands of the grating structures. The third grating structure has a grating period that is larger by a factor of 2 to 5 than the grating period of the first grating structure.

Measurement or imaging of elastic wave nonlinear scatterers with a memory of scattering parameters comprises selecting LF pulses having characteristics to change the scattering parameters of nonlinear scatterers. A transmit time relation is selected so that the incident HF pulse propagates sufficiently close to the LF pulse that the effect of the incident LF pulse on its scatterer parameters is observed by the HF pulse. At least two elastic wave pulse complexes comprising a high frequency (HF) pulse and a selected low frequency (LF) pulse are transmitted towards the region. Received HF signals are combined to form nonlinear HF signals representing the scatterers with memory, with suppression of received HF signals from other scatterers. At least one of the received HF signals may be corrected by time delay correction and/or speckle correction with a speckle correction filter, determined by movement of the scattering object. Systems are also disclosed.

The invention discloses a combined optimization algorithm of an inheritance multi-output support vector machine. The combined optimization algorithm combines with measured radar back scattering data for fast inversion of single-layer earth surface (root-mean-square height ksigma<1.5, and root-mean-square slope s<0.3) dielectric parameters and roughness parameters. The algorithm includes: using single-layer earth surface HH and VV measured polarizing radar back scattering coefficient data to obtain homo-polarization ratio; using a rough earth surface electromagnetic scattering small slope approximation method to calculate back homo-polarization ratio; combining a genetic algorithm with the small slope approximation homo-polarization ratio and the measured data to invert the earth surface dielectric constant; substituting the inversion result into an electromagnetic scattering integral equation model to generate a data file of back scattering coefficient changing with roughness; combining two kinds of measured polarized radar back scattering data to form a target function, using M-SVR optimization algorithm to invert the earth surface roughness parameters, and evaluating inversion errors and efficiency. By the combined optimization algorithm, real-time prediction of earth surface parameters can be achieved while inversion precision is guaranteed.

Onboard systems and methods for detection of airborne volcanic ash. One or more cameras are added to an aircraft. Each camera is configured to view a volume of air illuminated by a standard aircraft light, such as a strobe warning light (e.g., located on a wing tip) or a forward-facing landing light (e.g., located in the nose). Each camera is connected to a data processor. When diffuse volcanic ash is present, it scatters light transmitted from the standard aircraft light. Each camera converts impinging backscattered light into digital data which is sent to the processor. The processor processes the data from the camera or cameras to derive a measurement of the backscattered light and issues an alert when the amount and type of backscatter are compatible with the presence of volcanic ash.

A simple real-time femtosecond pulse measure instrument, which uses ultrashort pulse spectrum phase interfere directive electric-field reconstruction method to measure, including: the half-wave board, the quartz crystal, the scattering beam installment, he scattering beam installment, the large-angle Fresnel biprism, the thick non-linear crystal, the diaphragm, the wavelength spectrometer, the CCD detector and the computer, the advantages of the invention are: the equipment of wiping off the femtosecond pulse grating width, the real-time measurement, the higher measuring precision and lower cost.

A layered pad comprising a bottom impervious layer, a top layer of a fibrous high loft non woven capable of entrapping fine or coarse particles and preventing their scatter, optionally combined with a middle layer of fibers and super absorbent agent, wherein liquids pass through the top layer, become absorbed by the middle layer, and evaporate. As particles from an animal litter box or cage, shoes, metal cutting, wood shavings, and copy machines are generated, they immediately encounter the high loft non-woven top layer, which immediately immobilizes and then entraps them, preventing them from scattering. The filament count of the non-woven can be varied to design the pads to be more effective in trapping smaller or larger particles. In addition, a film of oily substance can be applied to the fibers to make them more sensitive to absorbing and entrapping extremely small particles. If absorbency is required under the high loft fibrous non-woven, a layer of absorbent material is added between the two layers. The layered pad is optionally treated with super absorbent polymer, deodorants, antibacterial agents, anti-fungal agents, and other substances depending on the use of pad.

The invention discloses an electromagnetic scattering analysis method of a target with a cavity on the basis of a moment method and a parabolic equation. The method comprises the following steps: firstly, filling the cavity body of the target with the cavity with solid metal, establishing a discrete model, determining the axial direction of a parabola as an x axis, and dispersing a target along the axial direction of the parabola by a mesh; in an x-axis direction, utilizing a CN (Crank-Nicolson) difference scheme to obtain a relationship between two adjacent tangent planes; in y-axis and z-axis directions, independently adopting an RPIM (Radial Point Interpolation Method) constructing fractal function and a spatial derivative to construct a matrix equation; successively carrying out recursive solving on a node electric field value on each tangent plane; carrying out solving on a cavity body part in the target separately by a fast multipole algorithm, applying an electric field integral equation to obtain current on the surface of the cavity body, and obtaining the electric field value of each discrete point required by the parabolic equation on an opening surface of the cavity body; and finally, carrying out postprocessing on the electric field on a last tangent plane to obtain a radar scattering sectional area. A meshless parabola and a fast multipole acceleration moment method are combined, and the electromagnetic scattering analysis method has the advantages of being efficient and reliable.

The invention relates to a target feature extraction method for one-dimensional imaging of a target by using a broadband radar. The target feature extraction method is used for solving the problems that the target features of a sea target are easily unstable under the influence of sea clutters when the sea target is subjected to broadband imaging, and the like, caused by the fact that the current broadband radar one-dimensional imaging method for the target mainly acquires the electromagnetic scattering characteristics of the external shape of the target. In order to obtain more stable identification results, a one-dimensional high-resolution distance feature extraction algorithm is provided by the technical scheme adopted by the invention, so that the accurate extraction of one-dimensional image features is realized, the discrimination and identification of one-dimensional broadband images of the sea target are realized. The target feature extraction method comprises the following specific steps of: judging the correctness of one-dimensional imaging data of the target so as to eliminate singular values which affect data computed results; accurately judging imaging starting and ending positions of the target so as to provide a basis for the judgment of target size and a support for back-end processing; and carrying out extraction and computation on numerical features of the target. The target feature extraction method provided by the invention has the advantages that the difficult problem in extraction of identification features of the target is solved, and a technical support for identification of broadband images of the target is provided.

The invention provides an ultra-wideband target electromagnetic scattering characteristic test system and method. The method includes: firstly, measuring a calibration object on a rotary table by fixing a first group of feed sources working on a first frequency band on a support capable of automatically switching the feed sources so as to continuously switch 2-27GHz plane waves emitted by the feed sources, and receiving reflected echo data; secondly, still performing 2-27GHz measurement by replacing a target object at the position of the calibration object; thirdly, after test ends, keeping the target object stationary, measuring the target object on the rotary table by 27-40GHz plane waves emitted by a second group of feed sources working on a second frequency band and receiving reflected echo data; fourthly, placing the previous calibration object at the position of the target object, performing calibration testing through the second frequency band, and receiving calibrated reflected echo data. Through the test data and by combining the data integrating technology, ultra-wideband target electromagnetic scattering characteristics of the target object can be acquired.

The invention provides a flexible electromagnetic scattering regulation and control structure. The structure comprises a flexible dielectric layer and a conductive pattern arranged on the flexible dielectric layer; the conductive pattern comprises conductive units arranged in an array; every two longitudinally adjacent conductive units are connected through a varactor; every two transversely adjacent conductive units are connected through a transverse direct-current bias line, and positive and negative voltage power supply buses are arranged on the two sides of each transverse column to form apower supply network; the varactors arranged in the same transverse row are the same in polarity; the varactors arranged longitudinally and adjacently are opposite in polarity; and all the varactorsare arranged in parallel. The invention further provides a manufacturing method of the electromagnetic scattering regulation and control structure. Flexible conformal coverage can be realized by utilizing the flexible electromagnetic scattering regulation and control structure, a greater role is played in electronic countermeasure, the probability that weaponry is detected is greatly reduced, andthe survivability of the weaponry is improved.

The invention discloses a plasma electromagnetic scattering modeling method based on the time domain shooting and bouncing rays method. The method utilizes rays to simulate the reflection and the refraction of electromagnetic waves in a multilayer plasma, and realizes electromagnetic scattering modeling of a plasma coated target by field strength tracking and far field solution of the rays. The method is an effective electromagnetic scattering modeling scheme for superhigh speed target in lean atmosphere, which enables the rapid modeling of the broadband scattering characteristics of the plasma coated target and greatly expands the scope of application.

A millimeter wave measurement system has been developed for remote detection of airborne nuclear radiation, based on electromagnetic scattering from radiation-induced ionization in air. Specifically, methods of monitoring radiation-induced ionization of air have been investigated, and the ionized air has been identified as a source of millimeter wave radar reflection, which can be utilized to determine the size and strength of a radiation source.

Defects of a hard disk drive servo pattern stamper are detected by comparing a scattered light beam pattern against the known servo pattern. A magnetic field is applied to stamper and the beam is linearly polarized. Variations in the physical offset of the beam, its scatter, are indicative of physical defects. Variations in the Kerr rotation of scattered beam are indicative of magnetic defects.

This invention is a vein synthesis method based on multi-pattern. By utilizing existing vein pattern, it scatters the seeds on the synthesized vein image buffer memory random according to the size of synthesized vein, the size and number of seeds that selected by user and different vein's proportion in the new synthesized vein. Then synthesizing vein using the vein synthesis method that L-shape based for all seeds in the four horizontal and vertical direction, until all the pixels in the synthesized vein image buffer memory have been synthesized.

The invention discloses a multi-probe quasi-far-field electromagnetic scattering cross section (RCS) extrapolation test system. The system is composed of a quasi-far-field electromagnetic scattering measurement system and a quasi-far-field electromagnetic scattering measurement data processing system. The first part realizes one-dimensional rotation of a target to be tested by controlling a turntable, and acquires an original signal required for quasi-far-field electromagnetic scattering measurement of the target to be tested by using a special test radar multi-probe circuit. The second part realizes acquisition of electromagnetic scattering data, and calculates a far-field horizontal plane RCS of the target to be tested according to a quasi-far-field-far-field transformation extrapolationalgorithm. The test system provided by the invention overcomes the limitation of the traditional electromagnetic scattering test means on the test distance and the size of the measurable target, reduces the influence of physical sizes among multiple probes, and has the advantages of high test efficiency and low cost.

The invention provides an efficient electromagnetic scattering modeling and calculation method for a composite target containing a wave-absorbing honeycomb structure, and the method comprises the steps: enabling a honeycomb wall to be equivalent to an impedance sheet during modeling of a hexagonal honeycomb structure, only remaining a uniform honeycomb unit as a body, and enabling a whole honeycomb region to become a uniform medium body containing a series of impedance boundary conditions, and simplifying the honeycomb modeling process. A non-conformal region decomposition technology is adopted to independently model a composite target partition containing a wave-absorbing honeycomb structure, so that modeling calculation of honeycomb structures of any shape and size becomes possible, and flexible and free geometric model creation, region division and mesh generation are allowed. After modeling and subdivision, efficient transmission conditions are set for different junctions between the sub-regions to ensure continuity of tangential electromagnetic fields on the surface and normal electromagnetic currents on the line, and the sub-regions are connected together. In the electromagnetic scattering calculation process, a matrix equation is obtained after an equation is dispersed, and the calculation process is simplified by introducing an IBC formula.

The invention discloses a synthetic aperture radar (SAR) target recognition method based on a component analysis multi-scale convolutional neural network, which mainly solves the problem of low SAR target recognition accuracy caused by insufficient mining of inherent information of an SAR target and difficulty in establishing a proper template library in the prior art, and comprises the following implementation steps: (1) generating a training set; (2) constructing a component to analyze a multi-scale convolutional neural network; (3) the training component analyzing the multi-scale convolutional neural network; and (4) classifying the SAR complex image to be classified. According to the SAR target identification method, the amplitude information and the electromagnetic scattering information of the SAR target are utilized at the same time, and the SAR images are classified through the network, so that the intrinsic information of the SAR target is more fully mined, a template library does not need to be constructed, and the accuracy of SAR target identification is effectively improved.