86 results about "Oblique incidence" patented technology

The invention discloses an airborne dynamic imaging-oriented image quality enhancement calculation processing system and a method thereof, and relates to the technical field of calculation optics. The system comprises an illumination module, a collimation module, a confocal module, a beam splitting module, an angle selection filtering module and an imaging module. The angle selection filtering module changes the incident angle of a light beam through physical movement or rotation, so that the angle selection filtering module excites a Berman mode in a near-zero dielectric constant double-layer film, and real-time switching between normal incidence low-pass denoising and oblique incidence high-pass sharpening is achieved. According to the invention, switching of two typical image processing functions can be realized only through incident angle adjustment without introducing an electrical regulation and control element, so that sharpening and denoising function integration is realized in a single optical structure, and the system has millisecond-level angle switching, low power consumption and a compact linear folded optical path, and is suitable for airborne high-speed imaging.

The invention discloses a low-frequency wide-angle light 3D (three-dimensional) metamaterial wave-absorbing structure. The wave-absorbing structure can realize a broadband wave-absorbing function with an average reflectivity of less than-10 dB in a frequency band of 0.5-2 GHz. The structural unit is composed of a planar resonant structure and a composite three-dimensional frame resonant structure, and the wave-absorbing structure is obtained by periodically arraying the unit structure. The wave-absorbing structure has the advantages of light weight, low-frequency broadband, excellent oblique incidence performance and the like, so that the wave-absorbing structure has a wide application prospect in the aspects of target stealth and electromagnetic protection.

The invention relates to the technical field of intelligent surface defect identification of an intelligent sensing detection and optical scattering method, and discloses a yoga mat surface defect automatic identification method based on an intelligent sensor. Establishing a two-dimensional coordinate and a discrete sampling array on the surface of a measured object, and unifying an installation posture; scanning the scattering intensity of each point according to a multi-angle sequence under fixed oblique incidence, and checking the integrity and the range; summarizing according to fixed angle weights to form an angular spectrum value matrix; carrying out point-by-point difference on the defect-free reference matrix to obtain a residual error, carrying out difference synthesis along rows and columns to obtain mutation intensity, and constructing a matrix; generating candidate anomalies according to a reference mutation statistics set threshold value; a connected domain is extracted on the grid in a four-adjacent mode, insufficient area is eliminated, and the center and the area are calculated; and outputting the number, the position and the area of the defects and performing visual marking.

Variable-angle ellipsometry is performed using a high speed polarization state modulator, a photodetector, and a digital micromirror device or spinning disk to encode the angle of incidence of light with a high sampling rate in a time domain or frequency domain. A variable-angle ellipsometer uses a high speed, axially stationary polarization state modulator, such as a photoelastic modulator, and a high speed detector, such as a photodiode, for high speed data acquisition. To acquire data at a plurality of incident angles, a lens is used to generate a large incident angle distribution along an optical axis that is at an oblique angle of incidence and discrete or combinations of incident angles of light are selected in a sequence in the time domain or modulated over a plurality of incident angles in the frequency domain.

Methods and devices relating to volumetric meta-optic structures. A method involves computationally designing a three-dimensional refractive index profile using an adjoint-based optimization process. The process optimizes for sorting light based on wavelength or polarization at specific oblique incidence angles and accounts for source divergence using Gaussian beam simulations. A mode overlap figure of merit is employed, optionally including terms to minimize crosstalk. Fabrication constraints like material binarization and minimum feature size are handled via differentiable filters. Physical crosstalk barriers may optionally be modeled during optimization. The resulting optimized profile defines a manufacturable multi-layer structure comprising patterned dielectric materials configured to perform the target sorting function efficiently under the specified oblique angle conditions. An array of such devices, potentially comprising structurally distinct elements optimized for different angles, can be integrated with an image sensor.

The invention provides a method for realizing ultra-high-speed translation of a Bessel beam by using double acousto-optic modulation elements, which is characterized in that the displacement in the x-axis direction and the displacement in the y-axis direction are changed at a high speed by quickly switching radio frequencies f1 and f2, so that ultra-high-speed punching on the surface of a workpiece is realized; meanwhile, each hole has excellent morphology consistency due to vertical incidence, so that the problem of hole shape distortion caused by inclined incidence at the scanning edge of a traditional galvanometer is avoided; that is to say, the all-solid-state diffractive optical element is adopted, no mechanical moving part exists, the limitation of mechanical inertia is completely eliminated, the response time of light beam displacement only depends on the change speed of a driving signal and the establishment time of the diffraction effect, the MHz-level control effect can be easily achieved, and the speed is several orders of magnitude faster than that of a traditional galvanometer. The method is especially suitable for application scenes such as laser processing, optical tweezers, confocal microscopic imaging and high-speed optical switches.

This application relates to the field of tunnel construction safety monitoring technology, and discloses an intelligent identification method for water seepage risk at the tunnel face in water-rich clay layers. This method controls an active infrared excitation module to project radiation in an oblique incidence manner, uses polarization imaging to acquire sequences and calculates Stokes vectors; calculates the degree of linear polarization based on the Stokes vectors and performs threshold segmentation to generate a water film distribution mask; uses the Stokes vectors to construct a polarization angle field reflecting local normal changes as texture features, solves the optical flow constraint equation to obtain the instantaneous velocity field; performs frequency domain transformation on the velocity field, extracts the proportion of low-frequency creep energy through power spectral density analysis, and determines the soil rheological softening factor; finally, combines the water film distribution, rheological softening factor, and instantaneous velocity field to construct a mudslide risk index. This invention utilizes polarization texture reconstruction to solve the problem of weak texture tracking and eliminates elastic vibration interference through frequency domain energy decoupling, effectively improving the accuracy of mudslide risk identification.

The invention relates to the technical field of ultrasonic phased array nondestructive testing, and discloses a metal pipe inner wall defect ultrasonic phased array detection probe and a metal pipe inner wall defect ultrasonic phased array detection method, the probe comprises an array transducer and a wedge block, the array transducer is connected with the wedge block through a connector, and the curvature radius of the end face of the bottom of the wedge block is the same as that of a metal pipe. The curvature of the end part of the probe provided by the invention is the same as that of the outer diameter of the pipe, so that good acoustic coupling can be realized, an oblique incidence sound beam forming a certain angle with the radial direction of a detected object can be formed, and ultrasonic waves can obliquely enter the side surface of a defect; the full-focus algorithm is adopted for imaging in the axial direction of the pipe, the detection sensitivity of inner wall shallow surface defects can be effectively improved, and the detection efficiency and reliability are improved.

The utility model is applicable to the field of optical detection, and provides a double-light-source oblique incidence semiconductor wafer surface quality detection system, which is characterized in that laser of a first laser sequentially passes through a spectroscope, a polaroid, a first convex lens, a diaphragm module and a second convex lens, and obliquely enters the surface of a semiconductor wafer to be detected; and laser of the second laser sequentially passes through the spectroscope, the polaroid, the first convex lens, the diaphragm module and the second convex lens, and obliquely enters the surface of the semiconductor wafer to be measured. The existing optical detection has the defects of small detection field of view, low diffraction resolution and difficulty in positioning, while the characteristics of two detection technologies, namely photoluminescence detection and angle resolution scattering detection, are combined, so that the two detection results can be simply and quickly obtained; and the defect detection of the surface and the subsurface of the semiconductor wafer sample and the quality evaluation detection of the surface roughness are completed.

This invention provides a method for measuring dielectric constant based on oblique incidence light reflection difference technology. The probe light emitted by the laser 1 is converted into p-polarized light by the polarizer 2, and then modulated into p-polarized light and s-polarized light by the photoelastic modulator 3. The p-polarized light and s-polarized light are emitted alternately at a frequency of 50 kHz, and after passing through the phase shifter 4, a fixed phase difference is generated. Then, the light is focused by the first lens 5 and obliquely incident on the surface of the sample 6 to be tested, with the incident range between 50° and 60°. The signal light reflected from the surface of the sample 6 to be tested is incident on the analyzer 9 after passing through the second lens 8. The analyzer 9 is used to zero the fundamental frequency signal of the system. The signal light after passing through the analyzer 9 is absorbed by the photodetector 10 and converted into an electrical signal. The electrical signal is demodulated by the first lock-in amplifier 11 and the second lock-in amplifier 12 into a DC signal, a fundamental frequency signal I (Ω), and a harmonic signal I (2Ω). The demodulated signal is acquired and processed by the data acquisition and processing unit 13.

The present application relates to a kind of optical detection systems with full-angle oblique incidence dark field illumination system, belong to wafer defect detection technical field, especially to full-angle oblique incidence dark field illumination system optical detection system.The optical detection system provided by the present application, by the combination of first cone lens and second cone lens, collimate incident laser beam as parallel annular light beam, then realize full-angle oblique incidence dark field illumination by annular reflector and annular focusing system, fundamentally overcome the problems of existing single light source directional sensitivity and high precision of installation and adjustment of divergent annular light beam, poor expansibility, while ensuring the advantages of dark field high contrast, high precision and non-destructive testing, significantly improve system detection sensitivity, installation and adjustment convenience and function expansion capability.

The application provides a kind of oblique incidence high-efficiency broadband long-wave light splitting film, the working angle of the light splitting film is 45°, the equivalent relationship of double-sided design and single-sided design under oblique incidence is established by numerical calculation, the target values of 45° single-sided transmittance and reflectivity are set, three kinds of refractive index alternating design methods are used for film system matching, the film system structure design optimization is completed, then the same film system is coated on the two sides of long-wave infrared substrate respectively, and the preparation of the light splitting film is realized. The purpose of the application is to realize the high-efficiency splitting of long-wave infrared window in the wavelength range of 7-12 μm with transmittance / reflectivity of 1:1 under 45° oblique incidence. The light splitting film has stable performance, small surface shape change and is suitable for optical systems such as imaging and detection.

The application discloses a kind of round bar piece ultrasonic testing methods, it is for the round bar piece of diameter not more than 12mm, comprising: selecting contrast sample;Radial in contrast sample is opened as artificial reflector along the direction of hole;Control probe so that incident sound wave is produced pure transverse wave by axial oblique incidence of contrast sample;Adjust the incidence angle and sensitivity gain of probe, so that the wave height of secondary reflected sound wave of artificial reflector is not lower than set threshold, to determine detection sensitivity and the optimum incidence angle of probe;Control ultrasonic wave is obliquely incident along the axis of contrast sample and the bar piece to be examined, control relative helical linear motion between probe and corresponding bar piece, and obtain corresponding ultrasonic reflection signal;According to the ultrasonic reflection signal of contrast sample and the bar piece to be examined obtained is compared to obtain the organization state of the bar piece to be examined.The application can realize the measurement and evaluation of the grain organization state inside round bar piece under the premise of not destroying material structure.

The invention relates to the field of optical detection instruments, and discloses a method and device for detecting geometric parameters of an optical fiber bundle end face, and the method comprises the steps: controlling light emitted by a light source to obliquely enter a to-be-detected optical fiber bundle at a preset angle and optimal illuminance; performing convolution operation on pixel points at different pixel positions in the end face image of the to-be-detected optical fiber bundle by adopting different convolution kernels to generate a gradient map; extracting an edge image of the gradient map, and performing ellipse fitting and circle fitting to obtain an ellipse parameter and a circle parameter corresponding to the fitted image; and geometric parameters of the to-be-detected optical fiber bundle are calculated. According to the method, a common illumination light source is adopted and obliquely irradiates the cladding and the surface of the coating layer, so that geometric parameter detection can be carried out on the optical fiber with the coating layer and the cladding layer, and meanwhile, specific convolution parameters, light source brightness, an oblique incidence angle adjusting method and the like in an image edge extraction algorithm are optimized; the device can adapt to optical fiber bundles with different lengths and different transmittances, and the detection efficiency and accuracy are improved.

The present invention discloses an electromagnetic wave finite-difference time-domain (FDTD) method and system based on anisotropic media conditions, relating to the field of electromagnetic detection. Starting from Maxwell's equations, the method involves the constitutive relationship of the medium in tensor representation, which is given anisotropic properties. The method creatively introduces transverse wave vector parameters into the classic one-dimensional FDTD method, replacing the transverse partial derivatives in Maxwell's equations that do not belong to the propagation direction with the corresponding transverse wave vector parameters. This method can realize a one-dimensional solution for two-dimensional or three-dimensional electromagnetic problems. By setting the corresponding transverse wave vector parameters, the field intensity distribution of the electromagnetic wave can also be calculated under different conditions of normal incidence or oblique incidence.

The invention discloses a system and a method for measuring the target landing speed of a dynamic explosion oblique incidence fragment, and solves the problem that the existing fragment speed measurement method is difficult to be suitable for a dynamic explosion fragment speed measurement scene with a severe environment and an uncertain track. The system specifically comprises a projectile body coordinate resolving module, a double-layer target breaking assembly, a distributed time measuring module, a real-time dynamic positioning instrument and a terminal data processing module. The output end of the projectile body coordinate resolving module is connected with the input end of the terminal data processing module; the output end of the double-layer target breaking assembly is connected with the input end of the distributed time measurement module, and the target surface is in a regular shape; the output end of the distributed time measurement module is connected with the input end of the terminal data processing module; and the output end of the real-time dynamic positioning instrument is connected with the input end of the terminal data processing module. According to the invention, the vertical component of the fragment targeting speed is measured through the low-cost broken target, and the incident angle of the fragment at each point is measured by using the high-speed camera, so that the low-cost measurement of the multi-point oblique incidence fragment targeting speed is realized.

This invention belongs to the field of two-dimensional lateral offset measurement technology, and provides a method for synchronous measurement of two-dimensional displacement of metasurfaces based on quasi-continuous domain bound states. The method includes: acquiring a metasurface lattice sample containing dual markers; determining the band structure of the quasi-continuous domain bound states and its corresponding resonant electric field distribution through electromagnetic field simulation; determining the correlation between the normalized coupling amplitude component and the overall bias vector direction through electromagnetic field simulation; establishing a multi-solution correspondence between the incident light polarization direction and the overall bias direction; determining a unique overall bias direction from the multi-solution correspondence based on the chiral spectral differences and full width at half maximum (FWHM) response exhibited by the dual markers under oblique incidence of circularly polarized light; and calculating the two-dimensional overlay error by combining the determined overall bias direction with the preset artificial bias information. Compared with traditional methods, this application achieves synchronous measurement of two-dimensional displacement in characterizing overlay errors in photolithography processes.

The application discloses a kind of rotary body parts crack defect single-side ultrasonic oblique incidence full coverage detection method, belong to the field of measurement and control, the implementation steps of this method include: the crack occurrence area of the step root of rotary body parts is divided into two adjacent regions A and region B;Ultrasonic wave is obliquely incident from the end face of one end of rotary body parts, so that the refracted transverse wave only propagates between the two end faces of rotary body parts, and the crack in region A is detected;Ultrasonic wave is obliquely incident from the same end of rotary body parts, so that the refracted transverse wave propagates using the step, and the crack in region B is detected.This method ingeniously utilizes the structure of the boss itself, so that only ultrasonic oblique incidence from one end of rotary body parts can detect the cracks of all angles at the step root of both ends of rotary body parts, improve the detection efficiency, and reduce the labor intensity.

The application discloses a kind of applied to layered stratum seismic motion oblique incidence three-dimensional modeling input method, belong to civil engineering technical field.The method includes the following steps: S1, modeling to each layer stratum;S2, under reflection and transmission, calculate time delay and amplitude ratio;S3, calculate model boundary point parameter;S4, to model parameter is assigned value.The application adopts the above-mentioned one applied to layered stratum seismic motion oblique incidence three-dimensional modeling input method, and the seismic motion input under layered stratum is more accurate, reduces the use of parameter on seismic wave propagation path, establishes layered stratum seismic motion input method, provides effective support for near-fault underground structure seismic motion response analysis, with very strong practicality.

The invention provides a well cementation quality evaluation and annulus medium propagation velocity determination method and device, and belongs to the field of well cementation quality evaluation.The determination method comprises the steps that waveform data received by a current depth point at different orientations are obtained based on oblique incidence ultrasonic logging, and the waveform data are obtained; the waveform data comprises full-wave waveforms of Lamb waves received by receivers located at different well depths; determining the average propagation time of the reflected wave corresponding to the current depth point in the annulus medium based on the waveform data received by the current depth point at different orientations; and based on the logging parameters and the average propagation time corresponding to the current depth point, determining an annular medium propagation speed corresponding to the current depth point. According to the method provided by the invention, the cement loss in the direction can be identified by independently depending on the propagation velocity of the annulus medium, so that the first-interface and second-interface evaluation of the well cementation quality is realized.

The invention provides a thin-layer strong-absorption mechanical adjustable three-dimensional wave-absorbing structure comprising a bottom plate which is provided with a plurality of basic structure units arranged in a periodic array. Each basic structure unit comprises a hollow frame installed on the bottom plate, a three-dimensional resistive frequency selection substructure arranged on the outer surface of the hollow frame and a nested height-adjustable metal reflection three-dimensional substructure located in the hollow frame and installed on the bottom plate. The invention has the following beneficial effects: through a simple and unique three-dimensional wave-absorbing structure design, the absorption performance with a reflection coefficient lower than-20dB in a range of 8-18GHz is realized, and good oblique incidence stability is achieved; the adjustable reflection coefficient under any incident angle in a broadband range is realized, so that the current requirements of a novel electromagnetic wave-absorbing material which is thin in layer, small in surface density, strong in absorption, adjustable in wave-absorbing performance, simple in structure and good in oblique incidence stability are met.

The present invention relates to the field of electromagnetic wave control technology, and discloses a broadband linearly polarized achromatic stealth metadevice under oblique incidence conditions, comprising a prismatic dielectric column consisting of an upper and lower rhombus-shaped bottom surface and four rectangular side surfaces, wherein two adjacent rectangular side surfaces are both first Huygens achromatic metasurfaces, and the remaining two adjacent rectangular side surfaces are both second Huygens achromatic metasurfaces; the present invention achieves broadband achromatic stealth under oblique incidence conditions by placing Huygens achromatic metasurfaces on the rectangular side surfaces of the prismatic dielectric column, while not significantly increasing the volume of the metadevice and saving resources.

The application provides a kind of wideband wide-angle wave absorber based on three-dimensional frequency selective surface, comprising a plurality of three-dimensional frequency selective surface units with same structure and continuous arrangement, each three-dimensional frequency selective surface unit is a hollow cuboid, and each three-dimensional frequency selective surface unit comprises horizontal structure, vertical structure and metal bottom plate arranged in sequence from top to bottom; the wave absorber provided by the application can significantly improve the angle stability of the wave absorber by combining the horizontal structure with the vertical structure, and for 0-60° oblique incidence of TE and TM waves, more than 90% absorption can be achieved within 2.1 times the frequency bandwidth; meanwhile, the wave absorber in the application has the advantages of low profile, small thickness and period size, is easy to integrate with other devices, and is high in convenience; in addition, a center-symmetric pattern design is used in each layer structure of the frequency selective surface unit in the application, which reduces the polarization direction sensitivity of the wave absorber to incident electromagnetic waves.

Embodiments of the present application provide an illumination shaping device for oblique incidence light beam, an optical equipment and a detection method. The illumination shaping device comprises a first aspheric mirror and a second aspheric mirror. A first generatrix of the first aspheric mirror is along a first direction. A second generatrix of the second aspheric mirror is along a second direction perpendicular to the first direction. The first aspheric mirror is used to form a first flat-top light spot distributed along a third direction on a detection surface. The second aspheric mirror is used to form a second flat-top light spot distributed along a fourth direction perpendicular to the third direction on the detection surface. Wherein, an initial light beam forms a shaped light beam after being modulated by the first aspheric mirror and the second aspheric mirror. When the shaped light beam is obliquely incident on the detection surface, flat-top light spots distributed along different directions are formed on the detection surface. In the oblique incidence state, the uniformity difference before and after the focal point is small, and a flat-top line light spot with good uniformity is formed, thereby providing good illumination performance for the detection surface.

The application belongs to the technical field of optical measurement, and discloses a micro area optical dispersion measurement system and method based on dark field scattering, which comprises a sample stage, an oblique incidence excitation module and a dark field collection module; the wide spectrum light output by the oblique incidence excitation module forms parallel light oblique incidence and irradiates on the sample; the dark field collection module comprises, from bottom to top, a collection objective, a first lens, a pinhole diaphragm, a second lens, a moving mechanism, a third lens and a spectrometer which are sequentially arranged above the sample; the sample is located at the front focal plane of the collection objective, the distance between the back focal plane of the collection objective and the first lens is equal to the focal length of the first lens, and the distance between the first lens and the slit is equal to the focal length of the first lens; the distance between the slit and the second lens is equal to the focal length of the second lens, and the distance between the third lens and the spectrometer is equal to the focal length of the third lens; the second lens is arranged in the light path of the dark field collection module through the moving mechanism, and the application avoids interference and improves the measurement precision through dark field scattering.

The invention provides a full-band three-dimensional wave-absorbing metamaterial, which comprises a plurality of basic structure units arranged in a periodic array, and is characterized in that each basic structure unit comprises a first electromagnetic loss three-dimensional superstructure to a sixth electromagnetic loss three-dimensional superstructure and a metal backboard which are sequentially arranged from top to bottom; the first electromagnetic loss three-dimensional superstructure to the sixth electromagnetic loss three-dimensional superstructure are loaded with resistive frequency selective surfaces. The invention has the following beneficial effects: the resistive frequency surface, the pure metal patch and the electromagnetic loss three-dimensional superstructure are combined to carry out multi-dimensional coupling absorption design, so that the full-band absorption performance is realized in the current L, S, C, X, Ku, K and Ka bands with relatively high utilization rate, and certain electromagnetic loss performance is still shown in the V and W bands; the thickness is small, and the maximum oblique incidence angle is not smaller than 70 degrees, so that the requirements of thin-layer and low-surface-density electromagnetic wave-absorbing materials working in the current full-frequency-band range are met.

According to the detection device and method, a laser emits a point light source, a light beam is collimated through a non-curved mirror, the aperture of input parallel light is controlled through a three-piece type variable beam expanding mirror group, the light beam is shaped through a shaping prism, and the light beam is reflected by a reflector after penetrating through a focusing mirror and an optical wedge, so that the light beam is formed. The method comprises the following steps: obliquely irradiating the surface of a detected target at a specified angle, acquiring a light spot effect by cameras placed at symmetrical angle positions, and performing area scanning and image acquisition processing on a wafer after adjusting the size and uniformity of light spots according to detection requirements. According to the invention, the problem of uniformity of inclined incident light spots can be solved, the size of the detected light spots can be adjusted at the same detection position, and the detection precision and the detection speed in the detection process can be flexibly controlled.

A full-coverage areal density measurement mechanism, comprising a plurality of groups of measurement units (1) distributed along the strip travel direction of a material under test. Each group of measurement units (1) is arranged on the same straight line along the web width direction of the material under test, two adjacent measurement units (1) in the web width direction of the material under test are respectively located on different straight lines, and the effective measurement widths of a plurality of measurement units (1) cover the web width of the material under test. Adjacent measurement units (1) are assembled together, so that full-coverage areal density measurement of any wide web material can be realized, and two adjacent measurement units (1) are not arranged on the same straight line, so that the influence of ray crossing on the accuracy of areal density profile measurement can be avoided; and in addition, a single measurement unit (1) has a relatively small ray fan beam angle, avoiding large-angle oblique incidence, and the difference in radiation quantity at different positions on an elongated light spot is small, ensuring relatively consistent results of areal density measurement across the entire web width.

The application discloses a kind of image quality enhancement computing processing systems and method for airborne dynamic imaging, it is related to the field of computational optics.System includes illumination module, collimating module, confocal module, beam splitting module, angle selection filter module, imaging module;Angle selection filter module changes the incident angle of light beam by physical movement or rotation, so that angle selection filter module excites Berreman mode in near-zero dielectric constant double-layer film, realizes the real-time switching of normal incidence low-pass denoising and oblique incidence high-pass sharpening.The application can realize the switching of two typical image processing functions by adjusting the incident angle without introducing electric control elements, so as to realize the functional integration of sharpening and denoising in a single optical structure, with millisecond-level angle switching, low power consumption, compact linear folding optical path, suitable for airborne high-speed imaging.