72 results about "Spherical harmonics" patented technology

Some embodiments of a method may include: obtaining information for a three-dimensional (3D) Gaussian model corresponding to a 3D scene, wherein the information comprises a set of attributes of the 3D Gaussian model; parsing the information for a first attribute of the set of attributes, wherein the first attribute corresponds to a position of the 3D Gaussian model; parsing the information for a second attribute of the set of attributes, wherein the second attribute corresponds to a covariance of the 3D Gaussian model; parsing the information for third, fourth, and fifth attributes, wherein the third, fourth, and fifth attributes correspond to first, second, and third sets of spherical harmonics coefficients associated with the 3D Gaussian model; parsing the information for a sixth attribute of the set of attributes, wherein the sixth attribute is an alpha coefficient for the 3D Gaussian model; and rendering the 3D scene using the parsed attributes.

The invention relates to the technical field of three-dimensional reconstruction, in particular to a lightweight three-dimensional reconstruction method and system based on a three-dimensional Gaussian model, and the method comprises the steps: constructing the three-dimensional Gaussian of a target scene based on a multi-view original image of the target scene through employing a 3DGS algorithm; identifying the minimum resolution of each Gaussian primitive in the three-dimensional Gaussian, setting a spherical region according to the minimum resolution, taking the intersection result of the spherical region and the Gaussian primitive as a region evaluation score, and trimming the redundancy region geometry in the three-dimensional Gaussian in combination with the opacity; and taking the maximum zoom scale of the Gaussian primitive as a spatial density proxy variable, and dynamically distributing spherical harmonic coefficient orders according to a local spatial density proxy variable so as to meet the rendering requirements of different three-dimensional Gaussian geometric regions. On the premise that the image synthesis quality is not lost, the model scale and the transmission overhead can be remarkably compressed, the resource constraint condition of the edge computing equipment can be effectively adapted, and the higher training speed and the better rendering effect are achieved.

The invention discloses a double-layer ionosphere modeling method fusing low-orbit satellite data, which comprises the following steps of: preprocessing ground-based GNSS (Global Navigation Satellite System) data to obtain an STEC expression of a ground-based GNSS; preprocessing the precise orbit determination data of the low-orbit satellite to obtain a VTEC expression of the precise orbit determination data; obtaining an electron density profile product of the radio occultation of the low-orbit satellite, and obtaining VTEC of the radio occultation through profile integration; using two groups of spherical harmonic coefficients to express global VTEC distribution, and constructing an observation equation; and determining weights of different types of data by using Helmert variance component estimation, and finally solving to obtain two groups of spherical harmonic coefficients to generate an ionized layer grid product. Projection errors caused by vertical layering in a traditional single-layer model are weakened, meanwhile, precise orbit determination data and radio occultation data of a low-orbit satellite are combined, the problem that ionosphere TEC cannot be correctly layered in a double-layer model is solved, data of areas where GNSS tracking stations are sparsely distributed are supplemented, and the reliability of the GNSS tracking stations is improved. Therefore, a global ionosphere model with higher precision is obtained.

The invention discloses a GRACE and Swarm time-varying gravity field fusion filtering method based on a state space model, and the method comprises the steps: taking a spherical harmonic coefficient as a state quantity, constructing a random walk process equation, introducing three types of observations, employing a quantization parameter for observation noise and process noise covariance, constructing according to an order / power law, and carrying out the self-adaptive updating along with the monthly; a Nelder-Mead method is adopted to search for spectral index parameters, and an EM algorithm and a statistical method are utilized to update other parameters in a closed / quasi-closed mode; obtaining the state and posterior covariance of a full time sequence by using Kalman filtering and RTS smoothing; in the GRACE and GRACE-FO window period, continuous reconstruction is carried out by means of a process model and Swarm; and outputting quality evaluation information including monthly gravity field coefficients, posterior covariance, innovative variance ratio, residual whitening test, space power spectrum, uncertainty band and the like. According to the method, while physical rationality and calculation feasibility are ensured, a continuous and stable monthly time-varying gravitational field sequence with quantifiable uncertainty is realized.

The invention discloses a GNSS (Global Navigation Satellite System) nonlinear deformation correction method based on a full-spectrum three-dimensional thermoelastic model. The GNSS nonlinear deformation correction method comprises the following steps: carrying out discrete Fourier decomposition on a temperature time sequence of each grid point; carrying out space spherical harmonic expansion and coefficient projection on each decomposed frequency; based on a space spherical harmonic expansion and coefficient projection result, considering the periodicity of the temperature, and performing sine / cosine representation of a frequency-by-frequency temperature item; performing spherical harmonic representation and time expansion on the deformed displacement field corresponding to the periodic temperature based on the spatial spherical harmonic expansion and coefficient projection result; solving a deformation equation in spherical coordinates in a Love number form to obtain an expression of a complex Love number; based on the complex spherical harmonic coefficient and the complex Love number of the temperature, full-spectrum synthesis of three-component displacement at the spherical surface is carried out; and performing internal consistency and external dispersion verification based on a full-spectrum synthesis result.

The invention relates to the technical field of three-dimensional reconstruction and rendering, and particularly discloses an underwater long-sight-distance adaptive three-dimensional reconstruction and rendering method based on a Gaussian variable-distance field, and the method comprises the steps: carrying out the initialization point cloud generation based on a motion recovery structure algorithm for RGB image data obtained by underwater image collection equipment; points on the initialized point cloud are combined with a three-dimensional Gaussian distribution model, a three-dimensional Gaussian primitive is defined, and parameter initialization about information such as a Gaussian geometric center, a three-dimensional covariance matrix, opacity and color is carried out on the three-dimensional Gaussian primitive; the method comprises the following steps: establishing a Gaussian cross-space transformation model, performing transformation from a Cartesian coordinate space to a homogeneous coordinate space on a three-dimensional Gaussian primitive, establishing a Gaussian full-parameter space mapping model, mapping color information of the three-dimensional Gaussian primitive after cross-space transformation into a spherical harmonic function, and spatial adaptive three-dimensional reconstruction and rendering in an underwater long-sight-distance environment are realized.

The invention discloses a global ionosphere modeling method based on a spherical radial basis function, and the method comprises the steps: laying Reuter grid points at an interval of 10 degrees on an ionosphere thin layer, and converting the Reuter grid points into a daily fixed geomagnetic coordinate system for modeling. Cycle slip monitoring and abnormal value identification and elimination are carried out on obtained satellite observation data (O file), then a precise satellite orbit position is obtained through interpolation in combination with a precise ephemeris file (SP3), hardware deviation is corrected through differential code deviation (DCB file), an AbBPoisson spherical surface radial basis function is adopted and converted into a 15-order truncated AbBPoisson spherical surface radial basis function, and finally, a precise satellite orbit position is obtained. The bandwidth is set to be 0.25, L2 regularization optimization is used, parameters of a radial basis function are solved through a least square method, and therefore global ionosphere modeling is carried out. Different from a traditional spherical harmonic function method, the abbeposon spherical radial basis function controls the control range of a radial base point by adjusting the bandwidth, higher precision can be provided in a data-intensive area, and the adaptability is higher.

The invention relates to the field of array signal processing, and discloses an underwater target azimuth estimation method based on spherical harmonic noise model sparse reconstruction, which comprises the following steps of: calculating array output data to obtain a sample covariance matrix, establishing a spherical harmonic noise model, expressing spatial noise power density by adopting a finite-order spherical harmonic function, determining an initial power spectrum, and estimating the azimuth of an underwater target according to the initial power spectrum. Initializing the spherical harmonic noise model to obtain a noise covariance matrix, determining an expected model covariance matrix according to the noise covariance matrix, performing peak search on the initial power spectrum to obtain an estimated orientation, and refitting based on the estimated orientation to update the noise covariance matrix and the expected model covariance matrix; the initial power spectrum is subjected to sparse reconstruction based on the expectation model covariance matrix and the sample covariance matrix before updating to obtain an updated power spectrum, when the difference between the updated power spectrum and the initial power spectrum meets the convergence condition, the peak value of the updated power spectrum is searched to determine the target orientation, and super-resolution and robust orientation estimation is achieved.

The invention provides a three-dimensional semantic scene completion method and system based on semantic-physical joint representation. The method comprises the following steps: extracting image features according to multi-view image input, and mapping the image features to a three-dimensional voxel space; voxel features containing local semantic information and three-view features containing global semantic information are extracted through a double-branch encoder, key anchor points with identifiable semantic features are screened out according to semantic consistency of the voxel features and the three-view features, and efficient initialization of Gaussian representation in a key area is guided; and then introducing a semantic spherical harmonic function, projecting Gaussian semantic representation to an orthogonal spherical harmonic space, enhancing the modeling capability of local context geometric structure information, and promoting the semantic-geometric representation consistency of the context by using key voxel distribution alignment, thereby realizing three-dimensional semantic scene completion with both precision and efficiency.

A system generates initial Gaussian elements defined by parameter sets that include, for each Gaussian element a spherical harmonics (SH) coefficient array, a learnable parameter vector, and a learnable weight vector. The system performs a training process comprising rasterizing current Gaussian elements to generate a rendered image of the scene as viewable from a current camera position, wherein for each Gaussian element of the current Gaussian elements that intersects the camera ray, the system determines an opacity value for a location based on a view-dependent scaling value that depends on the current camera position, a position vector, and the learnable parameter vector.

The invention provides a precise point positioning method, system, equipment and medium in an ocean scene, and belongs to the field of satellite navigation positioning, and the method comprises the steps: obtaining IGS-ZTD data and GGOS-ZTD data of different observation stations on the land, obtaining time sequence daily average deviation value data through calculation, inputting the data into a fitting model, carrying out the spherical harmonic expansion after fitting, and carrying out the precise point positioning. And obtaining a spherical harmonic function deviation model of the land area. Acquiring longitude and latitude of the ocean observation station, performing fitting calculation by using a spherical harmonic function deviation model, and introducing a dynamic order screening mechanism of a monthly scale to obtain a correction deviation value of the ocean observation station in the current month; and fitting ZTD data is obtained according to the correction deviation value. The regional limitation of a GNSS observation station is broken through, and the positioning precision of GGOS-ZTD data in an ocean region is improved by constructing a collaborative correction framework. And applying the fitted ZTD data to precise single-point positioning of an ocean scene to realize high-precision positioning of the measuring points in the ocean area.

To implement interpolation of discretely represented light rays through mathematically grounded procedures and systematically compress data.SOLUTION: A surface light field compression device includes: spherical harmonic function expansion means which determines the n-th (n is a natural number) coefficient to be obtained when expanding surface light field described with a set of one or more light rays, using a spherical harmonic function; coefficient multiplexing means which generates light ray data of which the first to the T-th (T is a natural number) coefficients are associated with start point coordinates of the one or more light rays, out of the coefficients determined by the spherical harmonic function expansion means; and light ray multiplexing means which multiplexes one or more pieces of light ray data generated by the coefficient multiplexing means to represent a set of light rays emitted from at least one of an object surface and the space. The set of light rays emitted from at least one of the object surface and the space is modeled.SELECTED DRAWING: Figure 1

The invention belongs to the technical field of underwater sound channels and physical fields, and relates to a numerical mixing calculation method for a forward scattering sound field of an underwater regular-shape object. The method comprises the following steps: acquiring an initial projection contour of a three-dimensional geometric model of a regular shape object in a specified projection plane and an incident direction; discrete points of the initial projection contour are divided into upper boundary points and lower boundary points; performing interpolation completion on the upper boundary points and the lower boundary points, so that the upper boundary points and the lower boundary points are the same in number and share abscissas; discretizing the supplemented projection contour by using a trapezoidal plane element; calculating a forward scattering far field morphological function based on a discretization result; and calculating the forward scattering target intensity of the object. The method provided by the invention can cover the shape range of the scattering object suitable for the analysis method, does not need to calculate special functions such as Bessel and spherical harmonic and a complex series expression formed by combining the special functions, and obviously improves the calculation efficiency.

The invention belongs to the technical field of hydrological monitoring, satellite gravity measurement and navigation positioning crossing, and particularly discloses a method for obtaining land water reserves through Beidou and GRACE combined inversion in a frequency domain, and the method comprises the steps: obtaining Beidou data and GRACE data, and carrying out the preprocessing of the Beidou data and GRACE data; establishing a spherical harmonic function, and performing calculation on the preprocessed Beidou data through the spherical harmonic function to obtain a spherical harmonic coefficient of the earth mass load; establishing a Slepian primary function in the local region, and calculating a hydrological load on the surface of the region; establishing a quantitative relation between the earth surface vertical displacement and the regional surface hydrological load in the Beidou data, and calculating the equivalent water height of a first region; meanwhile, the preprocessed GRACE data are converted into the equivalent water height of a second area through a Slepian basis function; and fusing the equivalent water height of the first region and the equivalent water height of the second region in the frequency domain to obtain a land water reserve change result. According to the invention, the TWS inversion effect can be improved.

The invention discloses a gradient coil design method and system for a rotary surface. The method comprises the following steps: providing a wiring surface required by a gradient coil to be designed and the structure and size of a target area; representing a bus on the wiring surface in a parameter equation form; representing a flow function of the current as series expansion located on the wiring surface; setting a to-be-solved target field and an allowable error, wherein the target field of the linear region is set based on the coefficient of the magnetic field spherical harmonic wave; establishing a spherical harmonic magnetic field sensitivity matrix and a power consumption matrix based on the stream function and the target area; establishing an optimization problem by taking coil power consumption as an optimization objective function and target field deviation as a constraint, and solving the optimization problem to obtain stream function distribution; and discretization is carried out based on stream function distribution to obtain coil wiring characteristics. The method can be suitable for the design of the gradient coil on the complex curved surface only by using a small number of variables, greatly improves the calculation and parameter optimization efficiency of the coil, and facilitates the reduction of the discomfort of a matrix.

This invention discloses an artificial intelligence-based method, system, and storage medium for generating panoramic sound audio. The method includes the following steps: S1. Inputting the original audio signal and scene parameters, obtaining the time-domain-frequency domain features and spatial scene features of the original audio signal through a multimodal feature extraction algorithm, and weighted fusing the time-domain-frequency domain features and spatial scene features to obtain fused features; S2. Constructing the mathematical expression basis of the 3D spatial sound field model based on the spherical harmonic function, mapping the fused features to three-dimensional spatial coordinates through a sound field modeling algorithm to obtain the 3D spatial sound field model; S3. Using an adaptive rendering algorithm, converting the 3D spatial sound field model into multi-channel panoramic sound audio output according to the parameters of the target playback device. This invention achieves automated panoramic sound audio generation by inputting the original audio signal and scene parameters for feature extraction, fusion, and sound field modeling, and converting the output based on adaptive rendering. It has the advantages of automation, high efficiency, and high precision.

The invention discloses a panoramic sound audio generation method and system based on artificial intelligence, and a storage medium, and the method comprises the following steps: S1, inputting an original audio signal and scene parameters, obtaining the time domain-frequency domain features and space scene features of the original audio signal through a multi-modal feature extraction algorithm, carrying out weighted fusion on the time domain-frequency domain features and the space scene features to obtain fusion features; s2, constructing a mathematical expression basis of a 3D space sound field model based on a spherical harmonic function, and mapping fusion features to three-dimensional space coordinates and the 3D space sound field model through a sound field modeling algorithm; and S3, converting the 3D space sound field model into multi-channel panoramic sound audio output according to the parameters of the target playing equipment by using an adaptive rendering algorithm. According to the method, feature extraction, fusion and sound field modeling are carried out by inputting the original audio signals and scene parameters, automatic panoramic sound audio generation is realized based on adaptive rendering conversion output, and the method has the advantages of automation, high efficiency, high precision and the like.

The invention relates to the technical field of neutron transport numerical calculation, in particular to a cross section generation method and device based on flux moment homogenization and transport correction coupling and a storage medium, and the method comprises the steps: S1, building a geometric model of a reactor assembly or lattice cell, carrying out the energy Monte Carlo calculation, and generating a conventional cross section based on statistical data; s2, extracting a spherical harmonic function flux moment and a total reaction rate moment, calculating a total cross section spherical harmonic function correction term, and introducing a conventional scattering cross section to complete flux moment homogenization correction; and S3, exporting a first-order scattering matrix, carrying out transport correction to obtain a transport correction term, and correcting the conventional cross section according to the transport correction term and the total cross section spherical harmonic function correction term to generate a final multi-group cross section. According to the method, the anisotropies of the total cross section and the scattering cross section are synergistically corrected, the calculation precision of the method in the strong anisotropy problem is improved on the premise of keeping the standard cross section data structure, and the compatibility with a widely applied reactor core calculation program is ensured.

Techniques to handle the Spherical Harmonic (SH) coefficients associated with 3DGS towards effective compression are described herein. SH coefficients are used to represent view dependent RGB color values, which takes a significant amount of memory—48 out of 59 parameters per Gaussian. By applying suitable transformation to SH coefficients, the inter-channel redundancies are exploited, thereby effectively reducing the memory requirements by 50%.

A preparation method of a metamaterial with continuously distributed physical attributes comprises the following steps: firstly, introducing a spherical harmonic function to realize unique representation and optimization of a physical attribute field, realizing spatial continuous transition of the physical attribute field, generating a metamaterial structure meeting functional requirements, and then preparing the metamaterial by adopting an additive manufacturing method. According to the method, physical attribute fields (such as rigidity and heat conductivity) and corresponding geometric structures of the structure can be represented and optimized according to functional requirements of the structure under actual service conditions, automatic design of the metamaterial with continuously distributed physical attributes can be realized, and the method has higher flexibility and universality in design of bearing and heat-conducting structures.

The invention belongs to the technical field of ionosphere physics, and particularly relates to a Chinese low-latitude region ionosphere TEC empirical model based on multi-source data fusion, and the modeling process comprises the steps: selecting multi-source TEC data of a solar activity cycle in a Chinese low-latitude region as a multi-source data set; determining the weight of each type of data through a Hall model variance component estimation method, and determining the weight of each type of data; carrying out data fusion on various data in the multi-source data set by utilizing the determined weight through a form of a 15-order 15-order spherical harmonic function to obtain a modeling data set; setting components of the TEC empirical model, and establishing a nonlinear mathematical expression to represent all the components; and calculating to-be-estimated parameters in the nonlinear mathematical expression of each component through nonlinear least square fitting, forming a TEC empirical model, and finishing final modeling. According to the method, the modeling precision of the Chinese low-latitude region is effectively improved, and the temporal and spatial change rule of the TEC can be described more accurately.

The application relates to a satellite collision probability estimation method, device and readable storage medium. The satellite collision probability estimation method comprises the following steps: forward propagation of a non-Gaussian relative velocity probability density function to obtain a reference velocity histogram, so as to determine an initial parameter set of a Gaussian mixture model; every first preset time interval, a plurality of sets of distance residuals and angle residuals of a first satellite and a second satellite in a running state are updated, so as to update the parameter set of the Gaussian mixture model; every second preset time interval, the relative positions of the first satellite and the second satellite are updated, and the instantaneous collision volume of the first satellite and the second satellite is determined by using the separation axis theorem; the mean values of Gaussian components in the updated parameter set are substituted into a static spherical harmonic coefficient table for query, so as to obtain the relative position probability density of the first satellite and the second satellite; and the collision probability is obtained based on the instantaneous collision volume and the relative position probability density, so that fast and accurate estimation is realized.

The invention discloses a complex particle three-dimensional morphology digital twinning method based on a spherical harmonic function and principal component analysis, and the method comprises the steps: (1) employing a three-dimensional scanner to scan a real particle morphology so as to obtain a triangular mesh data file of a particle surface morphology, and employing a self-adaptive curved surface optimization algorithm to optimize a scanned particle triangular mesh; (2) performing shape scaling on the particles to obtain spheroids by using triangular surface grid data after particle scanning optimization, and performing 30-order spherical harmonic function expansion on the spheroids to realize parameterization and digital reconstruction on the particles with complex morphology; and (3) performing principal component analysis on the shape parameters and the spherical harmonic function parameters of all the scanned particles to obtain characteristic values and characteristic vectors of a parameter matrix, constructing random morphology parameters based on the characteristic values and the characteristic vectors, and constructing a brand-new random particle surface morphology through the reverse process of the step (2). According to the method, basic guarantee is provided for quantitative analysis of the three-dimensional morphology of the surface of the complex granular material and performance analysis of the granular composite material.

The invention relates to the technical field of geophysical exploration methods, in particular to a magnetic model construction method based on geomagnetic data constraint inversion and width learning. The method comprises the following steps: S1, processing and fusing multi-source data to obtain processed and fused data; s2, performing physical constraint embedding according to the processed and fused data to obtain data after physical constraint embedding; s3, step-by-step inversion is carried out according to the data after physical constraint embedding, and a spherical harmonic coefficient dynamic correction term is obtained. According to the magnetic model construction method based on geomagnetic data constraint inversion and width learning, incremental updating is conducted, by dynamically adjusting feature nodes and enhancing nodes, only local weight re-calculation is needed, online model updating is achieved, the calculation efficiency is improved by more than 50%, node expansion is automatically triggered according to new data errors, and over-fitting / under-fitting is avoided.

This application relates to the field of water storage analysis technology, and provides a method and related equipment for jointly inverting changes in terrestrial water storage. The method includes: acquiring a hydrological model and surface deformation data of a target area, and constructing basis functions for the target area; performing spherical harmonic analysis on the hydrological model to convert it into spherical harmonic coefficients; establishing a first observation equation between the spherical harmonic coefficients and the basis function coefficients, and establishing a second observation equation between the surface deformation data and the basis function coefficients; solving for the basis function coefficients based on the first and second observation equations to obtain the final coefficient vector of the basis functions; and calculating the change in terrestrial water storage in the target area based on the final coefficient vector and the basis functions. The method of this application can simultaneously improve the spatiotemporal resolution and accuracy of jointly inverting changes in terrestrial water storage.

The application discloses a kind of earth magnetic field horizontal component representation methods of removing pole singularity, comprising: based on adolf schmidt semi-normalized spherical harmonic theory, the spherical harmonic representation of geomagnetic field magnetic potential function is obtained by spherical harmonic polynomial expansion calculation method;With south pole or north pole as center, mirror center symmetry extension is carried out to great circle on sphere, so that each point on sphere has a mirror point, so that the mirror extension function of geomagnetic field magnetic potential function is obtained;Two-dimensional Fourier expansion is carried out to mirror extension function using double Fourier series, and double coverage function expansion is obtained;Based on double coverage function expansion, the horizontal component of geomagnetic field is calculated, i.e. the spherical gradient of spherical magnetic potential function is calculated.The realization is based on the existing IGRF model magnetic potential expansion coefficient, the magnetic field tangent vector representation is obtained without being polluted by pole problem, and a new modeling idea and calculation method of spherical tangent vector field are provided.

The small sample point cloud target classification method based on LSHW-Mamba network relates to the technical field of 3D point cloud processing and deep learning, and solves the problems that the existing technology focuses on feature mining in the Euclidean space domain, and under the condition of insufficient target samples, the feature representation ability of the target geometric structure is insufficient, and it is difficult to capture the key information for distinguishing similar objects. The present application explicitly analyzes the spectral response of the local geometric structure of the point cloud through the spherical harmonic function, combines the local spherical harmonic wavelet transform to realize the geometric feature extraction of the point cloud, simultaneously introduces the geometric gating mechanism to optimize the feature propagation efficiency of the Mamba model, models the target features in parallel with the Transformer attention branch, considers the relevance of the local and global features of the target, and improves the discrimination ability of the network model for the target under the small sample scene. The present application effectively solves the core problems of insufficient feature discrimination and decreased classification accuracy under the small sample condition.

The application provides a sea level budget closure calculation method and system based on spherical harmonic domain adjustment inversion, and belongs to the technical field of sea level budget calculation; the method comprises the following steps: obtaining independent observation sea level data of each multivariate component in sea level rise; converting the independent observation sea level data of each multivariate component in the obtained sea level rise together with the overall sea level rise rate from a spatial domain to a spherical harmonic domain to obtain corresponding spherical harmonic coefficients; constructing an error equation based on the spherical harmonic coefficients, and solving the error equation based on indirect adjustment theory to obtain correction coefficients corresponding to each multivariate component; and correcting the observation values of each multivariate component and converting them back to the spatial domain to determine the budget results of the corrected sea level multivariate components. Through error distribution, the application can inversely obtain more accurate proportions of each multivariate component in the sea level rise process, thereby providing theoretical support for related research on sea level rise.

The invention discloses a lattice cell scale two-step method reactor core physical analysis method based on a first-order spherical harmonic function, which comprises the following steps of: 1, performing full-component one-step method non-uniform neutron transport calculation to obtain neutron standard flux density and neutron angle flux density in the non-uniform transport calculation; 2, calculating a homogenized few-group cross section; 3, lattice cell discontinuous factor calculation; 4, calculating a diffusion coefficient matrix; 5, solving a P1 equation; 6, calculating power and thermotechnical feedback; and 7, if the nuclear thermal coupling converges, outputting three-dimensional power distribution for subsequent safety analysis. According to the method, the first-order spherical harmonic function equation is solved repeatedly based on the angle-related section, the calculation efficiency is remarkably improved while it is guaranteed that the calculation precision is equivalent to that in the prior art, and the calculation time is shortened by 40% or above; and accurate data support is provided for design analysis of the nuclear energy device.

The invention discloses a multi-view-based three-dimensional reconstruction model quality evaluation method and system and a medium, and belongs to the field of multi-view three-dimensional reconstruction model quality evaluation. Comprising the following steps that a model generated through multi-view three-dimensional reconstruction is obtained, and the surface of the model is a Lambert body surface; the rendering equation of the Lambert body surface is converted into a point multiplication form of an incident light spherical harmonic coefficient and a surface transmission characteristic spherical harmonic coefficient, and the surface transmission characteristic is a product of a binary visible function and a geometric cosine term; the real irradiance of the surface of the reconstruction model is reversely deduced through the pixel intensity of the multi-view image; based on the incident light spherical harmonic coefficient, calculating the reconstruction irradiance of the reconstruction model by using a spherical harmonic coefficient linear combination equation; if the difference value between the reconstruction irradiance gradient and the real irradiance gradient between any two points in the model is greater than a preset threshold value, determining that a geometric error exists in a three-dimensional reconstruction result between the two points; according to the method, which parts of the reconstruction model have errors can be accurately judged.