33 results about "Snell's law" patented technology

The invention discloses a monocular and binocular cooperative localization and mapping method and device for underwater refraction compensation, and the method comprises the steps: extracting checkerboard angular points, compensating an underwater light path through employing a two-time vector correction model based on a Snell law, and precisely calibrating the internal and external parameters of a binocular camera. According to the method, an underwater real light path is effectively restored, and calibration errors caused by medium refraction are remarkably reduced. Then epipolar correction is performed on the corrected left and right images, so that the geometric consistency of stereo matching is ensured; and finally, monocular and binocular poses are fused, and seven-degree-of-freedom similarity transformation global alignment is applied, so that the problem of monocular scale uncertainty is effectively solved, and high-precision and high-robustness three-dimensional mapping is realized by means of binocular real scale introduction. Key links such as camera pre-calibration, refraction compensation, image correction, monocular tracking, binocular depth measurement, scale alignment and the like are connected in series to form an integrated process, so that the underwater vision positioning and mapping precision is improved.

The invention discloses an underwater target identification and positioning method based on fusion of a physical model and deep learning, and belongs to the technical field of computer vision, and the method comprises the steps: carrying out the transmissivity estimation and physical restoration of a collected underwater monocular image according to an underwater light propagation model, and carrying out the image correction; key feature points are extracted, and high-quality matching point pairs are screened in combination with the joint similarity; further deriving a basic matrix through the high-quality matching point pairs meeting the epipolar geometric constraint relation, solving an essential matrix, and obtaining relative attitude parameters between the cameras in combination with weighted re-projection-LM optimization; and finally, refraction correction triangulation is carried out according to the Snell's law, pixel-level fusion is carried out after scale normalization and space alignment are carried out on the refraction correction triangulation and dense depth output by the MiDaS, three-dimensional space coordinates of the target are inverted, and high-precision recognition and positioning of the underwater target are achieved. The system is light in structure, efficient in calculation, suitable for being integrated on various underwater autonomous or remote control robot platforms and used for tasks such as target recognition, tracking and positioning.

The invention discloses an extremely shallow water blue-green laser sounding dynamic refraction vision correction method, which belongs to the technical field of marine surveying and mapping and underwater detection, is used for laser refraction correction, and comprises the following steps: synchronously acquiring binocular images and inertial measurement unit attitude data, and generating a three-dimensional point cloud; according to a light spot area in the laser emission angle index point cloud, fitting a micro-tangent plane to obtain a water surface original normal vector; calculating a confidence coefficient weight according to the image texture definition, and iteratively calculating an optimal estimation normal vector based on the original normal vector and the weight; calculating a real incident angle according to the optimal estimation normal vector and the laser emitting direction; calculating the direction vector of the underwater refracted light according to the Snell's law; and calculating the underwater three-dimensional coordinates of the target point by combining the propagation distance of the laser in the air and the water and the emission origin coordinates. According to the method, the visual confidence is introduced, so that the problem of data failure when the traditional visual sounding encounters water surface reflection, glare or broken waves is solved, and the robustness under the complex sea condition is remarkably improved.

The invention belongs to the technical field of underwater vision measurement, and relates to an underwater binocular vision system refraction parameter self-calibration method, which comprises the following steps of: firstly, constructing a space equation containing a water body refractive index, a refraction interface normal vector, an interface distance and a light path coefficient based on a Snell law; constructing a generalized state vector including an environment parameter, a structure parameter and a path parameter; a system residual equation is established by using different-plane light intersection constraint of binocular vision, and nonlinear iterative least square solution is carried out by constructing a generalized Jacobian matrix so as to realize adaptive calibration of an underwater vision system; according to the method, on the premise that water body parameters do not need to be predicted and high-precision mechanical calibration is not needed, the water body refractive index and the system structure parameters are synchronously solved, self-adaptive calibration of the underwater vision system is achieved, and the three-dimensional measurement precision and robustness in the complex water environment are remarkably improved.

The present application relates to the technical field of optical aspheric surface, especially points to a kind of free curved surface characterization method based on CGH lens zero position compensation detection optical path, with the detection of free curved surface as the guide, based on zero position compensation detection principle, according to ray tracing method, Snell's law, diffraction principle and equal optical path principle, using the parameters required by interferometer incident wave front as plane wave, compensator as single CGH lens zero position compensation detection system indirectly characterizes free curved surface shape, by using XY polynomial and Zernike standard phase polynomial, the mathematical description of free curved surface is realized in design stage can determine its measurement scheme, and according to the characterization method self-defined a kind of aspheric surface type, called zero position free curved surface.The free curved surface characterization method improves the degree of freedom of free curved surface shape and the feasibility of zero position compensation method, reduces the detection difficulty of free curved surface shape, realizes the function of zero position free curved surface design can be detected.

The application discloses an IMU light path structure based on multiple super surfaces, and the light beam generated by a laser 1 is divided into three mutually perpendicular light beams after the action of a beam splitting super surface 3, and then is converted into circularly polarized light and linearly polarized light by a polarization conversion beam splitting super surface 4, and is used for pumping and detection of a nuclear magnetic resonance gyroscope 5 respectively. The beam splitting super surface 3 is composed of polarization-insensitive cylindrical nanorods, and the incident light is split and corresponding deflection is generated by combining the generalized Snell law. The polarization conversion beam splitting super surface 4 is composed of polarization-sensitive rectangular nanorods and polarization-insensitive cylindrical nanorods, the rectangular nanorods are used for converting linearly polarized light into circularly polarized light, and the cylindrical nanorods maintain the linear polarization characteristics and realize light beam splitting and direction adjustment. The application adopts a single laser configuration, realizes efficient light field regulation and control based on super surfaces, avoids the problem that a traditional IMU light path system depends on multiple lasers, reduces the system volume, complexity and energy consumption, improves the stability and integration, and is suitable for high-precision inertial navigation applications.

The application discloses a method for correcting the vision of laser refraction in extremely shallow water, and belongs to the technical field of marine surveying and mapping and underwater detection, and is used for laser refraction correction. The method comprises the following steps: synchronously collecting binocular images and inertial measurement unit attitude data, and generating three-dimensional point clouds; indexing a light spot area in the point clouds according to a laser emission angle, fitting a micro tangent plane, and obtaining an original normal vector of the water surface; calculating a confidence weight according to the image texture definition, and iteratively calculating an optimal estimated normal vector based on the original normal vector and the weight; calculating a real incident angle according to the optimal estimated normal vector and a laser emission direction; calculating a direction vector of underwater refracted light according to Snell's law; and combining the propagation distances of the laser in the air and in the water and the emission origin coordinates, and calculating three-dimensional coordinates of a target point on the water bottom. The application introduces visual confidence, solves the problem of data failure of traditional visual depth measurement when encountering water surface reflection, glare or broken waves, and significantly improves the robustness under complex sea conditions.

Disclosed in the present application are a Huygens-metasurface-based transparent transmission unit and a manufacturing method therefor, and a Huygens-metasurface-based transparent transmission array. The unit comprises intermediate dielectric layers, a first metal layer, and a second metal layer. The array comprises a plurality of Huygens-metasurface-based transparent transmission units that are arranged in a rectangular layout. The method comprises: on the basis of the generalized Snell's Law, determining the phase distribution of a Huygens metasurface unit, and adjusting parameters of a double-arc structure, so as to obtain double-arc structure parameters; on the basis of the structure parameters, manufacturing metal layers and performing etching to make the metal layers form on surfaces of PET layers; and positioning a target on each PET layer, and by means of an optically clear adhesive, bonding onto glass the PET layers with the metal layers, so as to manufacture a transparent transmission unit. The embodiments of the present application can achieve high transmittance of electromagnetic waves and achieve easy deployment on existing windows, and extend the wireless-signal reception range in specific areas. The Huygens-metasurface-based transparent transmission unit and the manufacturing method therefor, and the Huygens-metasurface-based transparent transmission array, as provided in the present application, can be widely applied in the technical field of electromagnetic metasurfaces.

The invention discloses an underwater binocular camera calibration method based on laser assistance, and the method comprises the steps: firstly constructing an underwater stereoscopic vision binocular refraction-removing imaging model according to the Snell's law, and correcting an underwater imaging error; secondly, acquiring a camera internal reference matrix by using a Zhang Zhengyou calibration method; then, a laser range finder is used for projecting laser to the calibration plate to form a light spot, the center pixel coordinate of the light spot is extracted through a gray gravity center method, the three-dimensional coordinate of the light spot is calculated in combination with laser ranging data, and the initial value of an external parameter matrix of the binocular camera is solved; and finally, introducing a Bayesian optimization algorithm, and optimizing the constraint equation by taking minimization of a three-dimensional coordinate calculation error as a target so as to obtain an exact solution of an external parameter matrix of the camera. Through organic combination of a deep learning technology and binocular stereo vision, the parameter calibration precision of the underwater binocular stereo vision camera is improved, a reliable technical guarantee is provided for subsequent underwater concrete structure defect quantification, and the fine monitoring requirement in a complex water environment is met.

The present application relates to the technical field of optical aspheric surface, especially refers to a kind of splicing aspheric surface characterization method based on CGH lens zero position compensation detection optical path, with the detection of aspheric surface as the guidance, based on zero position compensation detection principle, according to ray tracing method, Snell's law, diffraction principle and equal optical path principle, using the parameters required by the zero position compensation detection system of interferometer incident wave front as plane wave, compensator as single CGH lens and diffraction surface as binary optical surface 3 or binary optical surface 4 to characterize aspheric surface surface shape, and according to the aspheric surface type defined by the characterization method, it is called zero position splicing aspheric surface.According to the splicing aspheric surface characterization method, the measurement scheme can be determined in the design stage through the mathematical description of splicing aspheric surface, which avoids the influence of stray light and projection distortion of CGH detection, reduces the detection difficulty of splicing aspheric surface surface shape, and realizes the function of zero position splicing aspheric surface design.

The invention discloses an anti-interference directional antenna tracking method based on an acoustic beacon, and the method comprises the steps: 1, carrying out the multi-mode acoustic sensing, collecting the acoustic signals of a target region through an acoustic sensor array, and enabling the acoustic signals to comprise a coding signal transmitted by an active acoustic beacon and a feature noise signal generated by a target, establishing a sound wave-electromagnetic wave bimodal sensing network, and realizing data fusion by adopting extended Kalman filtering; 2, target identification and positioning: estimating the spatial position of a target object by adopting a corresponding positioning algorithm based on the type of the acoustic signal; step 3, adaptive beamforming is carried out, beamforming is carried out by adopting an improved generalized Snell law, and phase compensation provided by acoustic sensing is introduced; the invention relates to the technical field of sixth-generation mobile communication, and the technical scheme has excellent sensing performance and communication reliability in a complex environment, and is suitable for various 6G application scenes such as smart cities, security and protection monitoring, emergency rescue and the like.

The invention relates to the technical field of industrial control, and particularly discloses an intelligent visual measurement and control analysis system for a resin separation interface, which is characterized in that firstly, through image acquisition and HSV (hue, saturation, value) color space transformation, interface characteristics are accurately positioned in a complex illumination and window dirty environment by utilizing a hierarchical semantic segmentation technology; further, according to the scheme, a traditional linear perspective mapping model is abandoned, a light path refraction compensation mechanism based on the Snell law is constructed, interface pixel coordinates are converted into a sight incident angle, the nonlinear lateral displacement is calculated in combination with the window glass thickness and the refractive index, and therefore the real physical height for eliminating optical distortion is reconstructed. Based on the high-precision data, the system generates a control instruction through a PID strategy to drive a field valve, and precise closed-loop automatic control over the resin regeneration process is achieved.

The invention discloses a three-dimensional reconstruction method for an underwater binocular system, and relates to the technical field of underwater optical three-dimensional measurement. The method comprises the following steps: receiving camera internal parameters and distortion coefficients calibrated by left and right cameras in the underwater binocular system in the air and relative external parameters between the two cameras; receiving plane equation parameters of a cabin mirror outer plane of the underwater binocular system in a left camera coordinate system and synchronous left and right image pairs of an object to be measured acquired by the underwater binocular system in an underwater environment, wherein the plane equation parameters comprise a normal vector n and a distance d from an original point to the plane; preprocessing the acquired left and right image pairs, and calculating a disparity map or a feature point corresponding relation by adopting a stereo matching algorithm; and a virtual image pre-calibration method is adopted to calibrate the initial error of the point cloud before and after correction, and the focusing parameter of the camera is adjusted. According to the method, cabin mirror interface parameters are accurately calibrated, strict light path tracking and the Snell law are combined, a physically accurate multi-refraction correction model is constructed, high-precision correction is carried out on the basis of traditional binocular reconstruction, and finally accurate three-dimensional coordinates of a real underwater object are obtained.

The invention provides an underwater sound tomography inversion precision and measurement distance improvement method and system based on a flexible sound energy reinforcing material, and the method comprises the steps: carrying out a simulation experiment in which parameters continuously change along with the position according to the Snell's law, and determining the sound velocity and thickness parameters of a to-be-prepared flexible sound energy reinforcing material through the relation between the refractive index and the sound velocity; the mass fraction of a matrix and a scatterer of the flexible sound energy reinforcing material is calculated, then the flexible sound energy reinforcing material is segmented based on parameter values and then prepared respectively, the flexible sound energy reinforcing material is obtained, finally, the temperature and the flow velocity are inversed through the transmission time difference of signals of the two hosts, and real-time temperature flow monitoring is achieved. The system can meet long-term real-time observation requirements of water flow of most estuaries and coastal areas, has the advantages of continuous monitoring, high energy utilization rate, high temporal-spatial resolution, wide coverage range, non-contact measurement, few required sites, high adaptability and the like, and provides technical support for hydrological monitoring engineering.

an objective is to provide an optical element which has no discontinuous portion between adjacent lenses, and which suppresses a reduction of a light efficiency and also an occurrence of variability in light distribution due to diffusion, etc. An optical element capable of diffusing incident light to a predetermined diffusion range, and includes a transparent body including concavity-and-convexity on at least one surface. The diffusion range is defined as an internal side of a singular closed curved line on a predetermined plane. The concavity-and-convexity includes a plurality of crests and valleys without a periodicity. When it is defined that a wavelength of the light is λ, a refractive index of the transparent body is n1, and a refractive index of a medium around the transparent body is no, the concavity-and-convexity has no portion where a gradient of the concavity-and-convexity changes by 180 degrees within a range in which a width is λ / (n1−n0). A region of the concavity-and-convexity with the gradient causing the incident light to be emitted and outgo to a region outside the diffusion range by Snell's law is equal to or smaller than 5% of the entire region.

The invention provides a tracking method of a two-dimensional ray forward modeling seismic gather. The method comprises the steps of establishing mathematical physical models corresponding to incident and reflected rays; tracking from the emergent angle beta 0 of the surface ray to the underground, tracking downwards layer by layer according to the Snell's law of refraction, calculating the incident point of the incident ray and the incident stratum interface, and calculating the travel time of the incident ray in each layer; according to the reflection law, performing ray tracing on the earth surface layer by layer according to the Snell refraction law, calculating intersection points of reflected rays and each stratum interface, and calculating travel time of the reflected rays in each layer; tracking a normal ray and a pre-stack trace gather imaging ray of each layer corresponding to the common midpoint trace gather; and determining a common midpoint gather according to the earth surface incidence point, the stratum reflection point, the earth surface emergence point and the normal ray passing through the common midpoint, and determining a seismic pre-stack gather according to the imaging ray and the equal-offset incidence and reflection channels. A model which is more complex and closer to a real stratum is established, and deeper research is carried out on seismic wave speed forward modeling simulation.

This invention discloses a metasurface and method for generating an orbital angular momentum vortex beam array. The metasurface includes a central region and N edge regions, which are symmetrically arranged along the central region. Each edge region comprises a unit structure with a gradually changing arrangement from the center to the edge. The edge regions deflect vertically incident linearly polarized light toward the central region. The deflection angle θ and the change in the unit structure size satisfy the generalized Snell's law. The method involves incident an expanded linearly polarized laser onto the metasurface, which, after transmission through the central region, is deflected and transformed into left-handed circularly polarized light (LCP) or right-handed circularly polarized light (RCP). The N edge regions, after transmission, generate a polarization angle θ toward the central region. The deflected beams interfere with the central beam to form a vortex beam array. The metasurface is composed of subwavelength structural units arranged periodically, with a size on the order of tens to hundreds of wavelengths, facilitating chip integration and producing a stable vortex array.

The application discloses an egg circle type scanning laser radar wave refraction correction error correction method, belongs to the technical field of airborne laser depth sounding, and is used for wave refraction correction of underwater terrain measurement of an airborne laser radar and comprises the following steps: filtering and processing sea surface point clouds by adopting a statistical outlier removal filtering method; extracting a sea surface slope normal vector corresponding to each point by adopting an optimized moving least square method; simplifying an egg circle type scanning laser radar measurement process to be carried out in a carrier coordinate system; constructing a refraction correction model by using Snell's law and a vector decomposition method; and obtaining corrected sea bottom point cloud coordinates. The application removes noise from sea surface point cloud data, fits the measured sea surface point cloud by using a moving least square method, adopts characteristic decomposition of a covariance matrix instead of polynomial fitting, and thus, the calculation is simple, polynomial fitting errors are avoided, the process is greatly simplified by using vector decomposition calculation, and there is only a single solution.

The invention discloses a geometric random underwater acoustic channel modeling method considering non-equal sound velocity. The method comprises the following steps: 1) constructing a shallow sea layered sound velocity profile; 2) multi-path propagation including a direct path, a sea surface reflection path and a seabed reflection path is considered; 3) calculating a propagation angle, a Doppler frequency shift, a propagation distance and a time delay parameter of a path between the receiving end and the transmitting end based on the layered sound velocity profile in combination with a geometric acoustic principle and a Snell law; and 4) establishing a channel impulse response and transmission function, calculating a time self-correlation function and a frequency correlation function at the same time, and performing analysis. According to the method, the non-equal sound velocity profile is introduced into the geometric random underwater acoustic channel model for the first time, the time-frequency fading characteristics of the channel under the equal sound velocity condition and the non-equal sound velocity condition are compared and analyzed, the physical authenticity and calculation precision of the model are improved, and reliable technical support is provided for design and performance evaluation of an underwater communication system.

The application relates to the technical field of optical aspheric surfaces, in particular to an aspheric surface characterization method based on a zero-position compensation detection light path of a spherical single lens, which is oriented to aspheric surface detection, based on a zero-position compensation detection principle, according to a light ray tracing method, Snell's law and an equal optical path principle, and characterized by various parameters of a zero-position compensation detection system required by an interferometer incident wave front being a spherical wave and a compensator being a single lens, and according to an aspheric surface type defined by the characterization method, the aspheric surface type is called a zero-position aspheric surface. The aspheric surface characterization method can obtain detection-related data in the stage of designing an optical system, and can modulate and constrain characterization parameters of the zero-position aspheric surface according to imaging requirements, so as to balance factors such as system imaging quality, aspheric surface structure, compensator and detection light path rationality, and realize the function of aspheric surface design and detection.

Described herein are systems and methods for refraction correction of OCT images configured for intraoperative use, including: a deep-learning model configured to receive a plurality of OCT images; and an imaging device configured to generate the plurality OCT images during an intraoperative procedure; wherein the deep-learning model is configured to map, in real-time, the plurality of OCT images to a two-dimensional vector field over a spatial domain of the plurality of OCT images; wherein the mapping is configured for real-time correction of refraction errors on the plurality of OCT images by employing Snell's law to generate a plurality of refraction-corrected OCT images via the deep-learning model. Other examples are described including features of the deep-learning model uniquely configured for interoperative usage such as an OCT image processing speed of 20Hz-50Hz.

The invention relates to a nondestructive testing system and method for deep small crack defects of a wind power composite material blade. The method comprises the following steps: reasonably arranging a to-be-tested composite material wind power blade in a water tank and adjusting the position of an ultrasonic array probe; calibrating the ultrasonic imaging system according to related detection standards; ultrasonic imaging parameters are set in the main control computer, and remote focusing acoustic beam control is realized based on a time delay rule and a Snell law; and obtaining three-dimensional ultrasonic data in the blade in a multi-subaperture traversal scanning mode. Received signals are processed by combining a ray tracing model, time delay matrix construction and a non-linear coherence measurement algorithm, high-resolution imaging of deep tiny crack defects of the composite material blade is achieved, and noise interference caused by material anisotropy is effectively restrained. According to the method, nondestructive and high-resolution detection of the deep tiny cracks of the wind power composite material blade can be realized, and the method has important engineering application value and popularization significance.

The application provides a two-dimensional ray forward seismic trace tracking method, which comprises the following steps: establishing a mathematical physical model corresponding to incident and reflected rays; tracking from a surface ray exit angle β0 to the underground, tracking layer by layer downward according to Snell's law of refraction, calculating an incident point of the incident ray and the incident stratum interface, and calculating the travel time of the incident ray in each layer; tracking layer by layer from Snell's law of refraction to the surface according to the reflection law, calculating the intersection of the reflected ray and each stratum interface, and calculating the travel time of the reflected ray in each layer; tracking normal rays of each layer corresponding to common midpoint trace sets and pre-stack trace imaging rays; determining the common midpoint trace set according to the surface incident point, the stratum reflection point, the surface exit point and the normal ray passing through the common midpoint; and determining the seismic pre-stack trace set according to the imaging ray and the equal offset incident and reflected trace. A more complex and more realistic stratum model is established, and a more in-depth study on the seismic wave velocity forward simulation is carried out.

The invention provides a design method of a light-emitting diode (LED) lighting system based on diffuse reflection and total internal reflection, which relates to the technical field of LED lighting design and utilizes the inherent Lambert radiation characteristic of an LED and the characteristic of an ideal diffuse reflection device to design the LED lighting system based on the luminous intensity distribution of an LED chip, the lighting requirement specified on a target plane, the energy conservation principle and the Snell law. A strict mathematical model is deduced, the obtained nonlinear equation set is solved, a series of two-dimensional profile curves are generated, and then the two-dimensional profile curves are synthesized into an off-axis free-form surface. Simulation results show that compared with a traditional diffuse reflector system, the lighting system achieves higher optical efficiency and better lighting uniformity. Besides, the method has certain universality, and the illumination requirements of other fields can be met only by optimizing and adjusting target plane parameters, so that the application prospect of diffusion indirect illumination in industrial production and daily life is effectively expanded.

The application relates to an ultrasonic-based aero-engine forge piece residual stress field detection method, which comprises the following steps: determining a corresponding acoustic elasticity control equation based on a linear relationship between ultrasonic wave velocity and stress of a forge piece material; calibrating an acoustic elasticity coefficient of the forge piece material; performing accurate measurement on a cross-sectional size of a forge piece to reconstruct a geometric shape of the forge piece; determining an acoustic beam scanning scheme based on Snell's law; performing multi-angle scanning excitation and receiving position and direction calculation according to the acoustic beam scanning scheme to collect ultrasonic receiving signals; calculating ultrasonic wave transit time and velocity according to the collected ultrasonic receiving signals; performing stress reconstruction inversion calculation on the geometric shape of the forge piece to construct a corresponding residual stress field; and performing three-dimensional imaging based on the corresponding residual stress field.

The invention discloses a method and a measuring system for solving birefringence phenomenon double-light tracks of a uniaxial crystal, and the method comprises the steps: defining a front surface normal vector, a rear surface normal vector and an optical axis direction vector of the crystal, and representing the spatial orientation of the crystal through the rotation operation around an x axis and a y axis; calculating a normal vector and an optical axis direction vector after rotation according to the rotation angle of the crystal around the z axis; based on the refraction law, the Snell law and the Fresnel equation, the propagation directions of the o light and the e light in the crystal are deduced; considering the refraction behavior of the rear surface of the crystal, and respectively calculating direction vectors after the o light and the e light are emitted; and determining the coordinates of the o light and the e light on the observation screen by utilizing a point equation and combining a ray tracing method, and rotating the crystal for one circle to generate a dual-light trajectory. According to the method, any crystal rotation operation is processed through a unified coordinate system, and the calculation complexity of a complex scene is reduced; the systematic intersection solution algorithm provided by the invention is combined with the e light wave vector / light separation calculation model, so that the light spot positioning efficiency is improved.

The disclosure provides a three-dimensional subglacial topography extraction method, device and equipment based on multi-channel ice radar data tomography processing and a storage medium. The method comprises the following steps: based on the ray tracing technology, a forward model database two-dimensional table is established by using Snell's law; a two-dimensional tomography output matrix corresponding to the target along the track position coordinates is established according to the multi-channel frequency wavenumber domain migration processing result; the distance and the incident angle corresponding to the maximum function value of the spatial spectrum function corresponding to the value in the normalized spatial frequency value range are determined according to the two-dimensional tomography output matrix and the normalized spatial frequency; the distance and the incident angle corresponding to the maximum function value of the spatial spectrum function corresponding to the value in the normalized spatial frequency value range are traversed based on the forward model database two-dimensional table to obtain the two-dimensional subglacial topography across the track direction at the target along the track position coordinates; and the three-dimensional subglacial topography is obtained by traversing the along-track position coordinates based on the two-dimensional subglacial topography across the track direction at the target along the track position coordinates.

A free-form surface imaging device based on light customized illumination and a free-form surface design method are provided. The method includes the following steps: determining basic optical parameters and a target pattern, and sampling the incident plane and a focal plane; roughly matching incident light and emergent light of the lens to obtain a roughly matched light pair; calculating a surface normal vector of the lens surface by using Snell's law according to the roughly matched light pair; based on the surface normal vector, constructing an initial surface by Poisson equation; performing fine matching on the initial surface to obtain a finely matched light pair; and based on the finely matched light pair, carrying out a global and a local optimization by adopting a hierarchical optimization method to obtain design surface data of the free-form surface lens. The imaging device includes a light source and the free-form surface.

The application relates to the technical field of optical aspheric surfaces, in particular to a non-spherical surface characterization method based on a CGH lens zero-position compensation detection light path, which is oriented to the detection of non-spherical surfaces, is based on a zero-position compensation detection principle, uses the light path tracing method, Snell's law, the diffraction principle and the equal optical path principle, uses the parameters required by a zero-position compensation detection system of an interferometer incident wave front, a compensator single CGH lens and a diffraction surface binary optical surface 2 to characterize the non-spherical surface shape, and according to a non-spherical surface type defined according to the characterization method, the non-spherical surface is called a zero-position non-spherical surface. The zero-position non-spherical surface has more flexible wave front modulation capacity, can realize the characterization of a continuous large-degree-of-freedom zero-position non-spherical surface shape with a curvature curve containing an inflection point, and can design a more compact optical system and improve the imaging quality of the optical system.

The application discloses an imaging device based on light customization free-form surface and a free-form surface design method, and the method comprises the following steps: determining basic optical parameters and a target pattern, and sampling an incident surface and a focal plane; performing rough matching on incident light and outgoing light of a lens to obtain a rough matching light pair; calculating a surface normal vector of a lens surface by using Snell's law according to the rough matching light pair; constructing an initial surface by using a Poisson equation based on the surface normal vector; performing fine matching on the initial surface to obtain a fine matching light pair; and performing global and local optimization by using a layered optimization method based on the fine matching light pair to obtain design surface data of the free-form surface. The imaging device comprises a light source and the free-form surface. The application can be popularized in different fields and applications by introducing a systematic design idea and an optimization strategy, and modularity and standardization of illumination system design are realized.