195 results about "Three dimensional geometry" patented technology

The invention discloses an intelligent monitoring, operation and maintenance platform and method for a soil covering tank based on digital twinning, and belongs to the technical field of digital twinning. A digital twinborn platform is used as a core, a physical geometry simulation module, an algorithm prediction module, a sensing communication module and a virtual visualization module are integrated, and the functional modules perform data interaction and cooperative work through the digital twinborn platform. Firstly, a physical geometric simulation module establishes a three-dimensional geometric model based on the actual structure of the soil covering tank and obtains multi-working-condition mechanical response data; secondly, collaborative prediction of external load distribution, structural response characteristics and fatigue damage is achieved through an algorithm prediction module; thirdly, the sensing communication module collects and processes sensor data in real time, and the model is driven to be dynamically updated; and finally, the virtual visualization module dynamically presents the multi-physical field state and damage evolution trend of the soil covering tank through a multi-source data fusion rendering technology. According to the invention, the comprehensive monitoring capability and failure early warning precision of the earthing tank are obviously improved, predictive maintenance decision is supported, and the operation and maintenance cost is reduced.

The invention discloses a surface mine digital safety production management method and device and a medium, and relates to the technical field of intelligent mines, and the method comprises the steps: collecting rock mass physical and mechanical parameters of a gold mine mining area and three-dimensional geometric morphology data of a blasting working face, and taking the parameters as physical constraint conditions to construct a digital twinborn body; a preset target blasting scheme is called to be input into the element reinforcement learning agent, multi-round simulation deduction is carried out through a blasting scheme evaluation strategy, and a simulation deduction result is generated; when the peak particle vibration velocity in the simulation deduction result exceeds a preset peak particle vibration velocity threshold value, generating a parameter adjustment suggestion; and the parameter adjustment suggestion is fed back to the element reinforcement learning agent for iterative optimization until the peak particle vibration velocity does not exceed a preset peak particle vibration velocity threshold, and a blasting scheme is generated. Through autonomous exploration of the meta-reinforcement learning agent in the blasting parameter space, the blasting scheme evaluation strategy with adaptability and reliability can be efficiently generated.

The invention discloses an electric arc additive manufacturing temperature field and stress field real-time reconstruction method, which comprises the following steps of: 1, constructing a sequential coupling finite element model in which heat conduction analysis and thermoelastic-plastic mechanical analysis are combined on the basis of process parameters of an electric arc additive manufacturing process and three-dimensional geometry of parts, generating a multi-physical field coupling data set among heat flux density, temperature and stress; step 2, constructing and training a neural network model based on a multi-physics field coupling data set, and realizing mapping from heat flux density to temperature and stress; 3, dynamically optimizing heat source model parameters in combination with real-time monitoring data and process parameters in the electric arc additive manufacturing process; and 4, based on the optimized heat source model parameters and the trained neural network model, real-time reconstruction of a temperature field and a stress field in the electric arc additive manufacturing process is achieved. According to the invention, the requirements of rapid sensing and intelligent regulation and control of temperature and stress states on an additive manufacturing site are met.

The embodiment of the invention discloses a robust extraction method for three-dimensional geometric features of a precast beam based on point cloud edge topology recombination. According to the technical scheme provided by the embodiment of the invention, the three-dimensional point cloud data of the precast beam is subjected to the surface domain separation to obtain the surface domain separation result, the plane fitting is performed according to the surface domain separation result to obtain the fitting plane, and the three-dimensional point cloud data is projected to the fitting plane to obtain the two-dimensional projection point cloud data; edge point detection is performed on the two-dimensional projection point cloud data to obtain a precast beam edge point set, ordered recombination is performed on the precast beam edge point set to obtain an ordered edge point sequence, and feature corner point extraction is performed according to the ordered edge point sequence to obtain precast beam corner points, so that the precast beam corner point extraction efficiency, accuracy and robustness are improved; the precast beam feature extraction efficiency can be improved, and the precast beam feature extraction precision can be effectively improved.

The invention discloses a physical attribute inversion and three-dimensional reconstruction method based on Gaussian splashing and micro-rendering, and belongs to the technical field of computer vision, and the method comprises the steps: generating a sparse point cloud based on a multi-view image to initialize a Gaussian ball; determining a Gaussian pivot point based on a Gaussian ball, constructing a self-adaptive tetrahedral mesh in combination with gradient optimization, extracting an explicit surface from the self-adaptive tetrahedral mesh, and sampling to obtain geometric information; predicting the physical attribute of each sampling point through an implicit texture network, and providing ambient light through an HDR ambient light map; geometric information, physical attributes and ambient light are used as input, a differentiable PBR renderer is adopted to generate a physical rendering image, multi-term loss function reverse optimization is constructed, and collaborative optimization and inversion of three-dimensional geometry and surface physical attributes are realized. According to the method, the problems of texture dislocation, thin-wall structure disappearance and high rendering calculation cost under dynamic topology are effectively solved, and a digital model with fine geometry and a realistic material can be efficiently recovered from a multi-view image.

The invention provides a GPU-based parallel tetrahedral mesh optimization method, system and device and a medium, and relates to the technical field of numerical simulation. Comprising the steps of generating a triangular mesh covering a surface for a three-dimensional geometric model; generating an initial tetrahedral mesh based on the triangular mesh; performing a round of point smoothing operation on each tetrahedron by using a plurality of GPU threads; carrying out iterative circulation of the combination optimization operation, and simultaneously carrying out a round of point smoothing, edge deletion and multi-surface deletion operation on a plurality of initial tetrahedrons by utilizing a plurality of GPU threads; and when the edge deletion operation and the multi-surface deletion operation cannot further improve the grid quality, simultaneously performing a round of edge contraction and edge segmentation operation on the plurality of initial tetrahedrons by utilizing the plurality of GPU threads. According to the method, the large-scale grid with reliable quality is quickly generated based on the low-quality input grid, and the grid optimization rate is improved, so that the requirement of large-scale unstructured grid optimization in a three-dimensional space is met.

The invention provides a bridge finite element model conversion method and system based on multi-algorithm matching, and the method comprises the steps: S1, based on a bridge BIM model, extracting a member number, the three-dimensional geometric information of a member and a mechanical-related hooking attribute, and calculating a section mechanical attribute; the component numbers serve as main keys, the three-dimensional geometric information, the hanging attributes related to mechanics and the section mechanical attributes are associated, and structural data are obtained; s2, through a component conversion algorithm, performing conversion based on the structured data to obtain a finite element component; and S3, connecting the finite element components to generate a complete bridge finite element model, and adding load information. Through the method disclosed by the invention, efficient and stable conversion between the BIM model and the finite element skeleton model can be realized, and meanwhile, the multiplexing efficiency of the BIM model data is improved.

Systems and methods are described for creating three dimensional models of building objects by creating a point cloud from a plurality of input images, defining edges of the building object's surfaces represented by the point cloud, creating simplified geometries of the building object's surfaces and constructing a building model based on the simplified geometries. Input images may include ground, orthographic, or oblique images. The resultant model may be scaled according to correlation with select image types and textured.

The invention relates to the technical field of solder ball array optimization, in particular to a low-warpage solder ball array optimization method and system in FC-BGA packaging of a glass substrate, and the method comprises the steps: determining the glass substrate and a plurality of solder balls, designing a preliminary array layout, creating a three-dimensional geometric model, carrying out the thermal loading simulation of the three-dimensional geometric model, and obtaining a plurality of thermal stress distribution nephograms; and executing the following operations on each thermal stress distribution cloud picture in the plurality of thermal stress distribution cloud pictures: obtaining a maximum thermal stress region from the thermal stress distribution cloud picture, obtaining a region position and a maximum thermal stress value according to the maximum thermal stress region, obtaining an optimal array layout, summarizing the optimal array layout, and obtaining the thermal stress distribution cloud picture. A plurality of thermal stress distribution cloud pictures are obtained, a plurality of optimal array layouts corresponding to the thermal stress distribution cloud pictures are obtained, the optimal array layout is obtained, the voidage of the welding spots is calculated based on the optimal array layout, and optimization of the low-warpage welding ball array in FC-BGA packaging of the glass substrate is completed based on the voidage of the welding spots. According to the invention, the optimization precision and efficiency of the solder ball layout can be improved.

A method for rapidly solving transient dynamics of a crack-containing bearing structure of a bogie belongs to the technical field of bogie structure dynamic analysis, and comprises the following steps: acquiring a three-dimensional geometric model of the bearing structure, the geometric dimension of a crack and the position coordinate dimension of the crack; dividing the finite element model of the bearing structure, and carrying out grid division processing on the crack surface; selecting a main degree-of-freedom node of the finite element model on the surface of the bearing structure and the crack surface; performing substructure analysis on the finite element model of the bearing structure; obtaining a mass matrix, a damping matrix and a stiffness matrix of the finite element model of the bearing structure after the degree of freedom is reduced; carrying out constraint simulation on a crack surface node by adopting a one-way nonlinear rigidity unit; processing constraint boundary conditions; processing the excitation load; and solving a dynamic second-order differential equation set, and judging whether the crack surface is in contact or not. According to the method, the opening and closing effects of the crack can be considered, the transient dynamic response of the crack-containing bearing structure under the action of the external load is obtained, and the solving precision and efficiency are both considered.

Disclosed in the present invention is a matrix transformation-based improved design method for a diffuser. Firstly, inlet and outlet position information of a diffuser is extracted, and then a double-coefficient adjustable polynomial is used to design a central line of the diffuser between the centroid of an inlet section and the centroid of an outlet section, and a change rule of the area of each section of the diffuser along the central line. In the aspect of transition of the shapes of an inlet and an outlet of the diffuser, once the inlet section and the outlet section have been mapped to a ξ-η space, a plurality of transition shapes between the inlet section and the outlet section are obtained by using a matrix transformation-based improved algorithm. The shapes of the inlet and the outlet, and each transition shape jointly form the shape of each local section of the diffuser along the central line. On the basis of the shapes of the sections, the change rule of the sectional area, and the change rule of the central line, the final three-dimensional geometry of the diffuser can be constructed under an o-xyz three-dimensional coordinate system, and the three-dimensional geometric modeling of the diffuser can be flexibly and controllably designed.

A method for predicting the occurrence of surface defects on sheet metal components configured for production in a forming process, the method comprising the following steps: A1 Creating a virtual graphical representation of a sheet metal component that can be produced in a forming process with a defined three-dimensional geometry (G1,...,G N ) and defined component properties (E1,...,E N ); A2 Execution of a computer program comprising an algorithm that checks the virtual graphical representation and / or a virtual state of the sheet metal component and determines whether deviations of the surface of the sheet metal component from the defined three-dimensional geometry (G1,...,G N ) given surface are to be expected or not, if the sheet metal component is subjected to a specific, predefined forming process (P1,...,P N); wherein the algorithm is generated by a method comprising machine learning, wherein the machine learning is performed by means of input data which is available as output from a plurality of finite element simulation steps with which the production of various individual sheet metal components each having different three-dimensional geometries (G1,...,G N ) and / or different defined component properties (E1,...,E N ) in a specific forming process (P1,...,P N ) can be at least partially simulated.

One embodiment of the present invention sets forth a technique for generating a geometry for a shape. The technique includes inputting, into a machine learning model, (i) a noise sample and (ii) one or more conditioning inputs. The technique also includes generating, via execution of the machine learning model based on the noise sample and the one or more conditioning inputs, a two-dimensional (2D) position map associated with the shape. The technique further includes generating a three-dimensional (3D) geometry for the shape based on the 2D position map.

The invention relates to the technical field of annular piece forging, and discloses a batch design method and device for the blank size of boss-section ring forgings, and the method comprises the steps: building a first three-dimensional geometric model of the ring forgings and a second three-dimensional geometric model of annular blanks with the same volume as the ring forgings according to the design structure of the ring forgings, based on the first three-dimensional geometric model and the second three-dimensional geometric model, a three-dimensional finite element model of the ring forging formed by rolling the blank is established; obtaining the wall thickness of the boss and the section filling rate of the ring forge piece when the wall thicknesses of different blank pieces are rolled to the design size of the ring forge piece; constructing a section filling rate analysis function based on the wall thickness of the blank piece and the wall thickness of the boss of the ring forging piece; workblank wall thicknesses corresponding to the wall thicknesses of the bosses of the different ring forgings are calculated; according to the design height of the ring forge piece and the workblank piece wall thickness obtained through calculation, the workblank piece inner diameter corresponding to the same workblank size can be obtained, the workblank size can be efficiently and accurately determined, the section shape and size precision of the ring forge piece are guaranteed, and the period is shortened.

The invention discloses a viscoelastic boundary verification method, device and equipment based on isoparametric elements and a medium, and the method comprises the steps: building a three-dimensional geometric model of a target structure according to geometric dimensions and material attributes, discretizing the three-dimensional geometric model into initial three-dimensional subunits, and then building an initial finite element mesh model; after identifying a target boundary surface to be applied with an artificial viscoelastic boundary, assigning boundary parameters to obtain each three-dimensional subunit and form a finite element model; all the three-dimensional subunits are mapped to a standard unit through equal-parameter coordinate transformation, an equivalent stiffness coefficient matrix and an equivalent damping coefficient matrix are obtained through calculation and then stacked and assembled, and an overall stiffness matrix and an overall damping matrix are formed; and calculating displacement response data based on the overall stiffness matrix and the overall damping matrix. According to the embodiment of the invention, by introducing the isoparametric coordinate transformation, the irregular boundary form can be directly processed without introducing an additional boundary unit, and the calculation requirement of an actual complex engineering model is met.

The invention discloses a geometric deviation detection system based on a pipe fitting, particularly relates to the field of image processing and three-dimensional geometric measurement, and is used for solving the problem of unstable geometric deviation judgment caused by cross section mixing under the conditions of step transition and shielding reflection of an inner cavity of the pipe fitting. Collecting a multi-view depth image and generating an original point cloud, and combining to form a unified point cloud after de-noising registration is completed; establishing an axial coordinate and a slice interception window according to a detection direction to obtain a candidate slice point set and construct an axial density curve, and generating a layering boundary through peak structure discrimination and segmenting the layering boundary into a layering point set; projecting the layered point set to a reference plane to form an initial section point set, taking an outer edge by adopting angle segmentation to obtain section contour points, fitting to obtain section geometric parameters, and determining a pure section point set by combining adjacent axial position consistency evaluation; and the section geometric parameters reflect the uniform point cloud to calculate the radial residual error and perform self-consistent judgment, and when the self-consistent judgment is not performed, the center of the slice interception window is driven to correct, and a stable geometric deviation detection result is output.

One embodiment of the present invention sets forth a technique for training a machine learning model on a geometry generation task. The technique includes generating, via execution of a diffusion model, a first set of training output corresponding to a first set of three-dimensional (3D) geometries based on a first set of conditioning inputs associated with a first conditioning mode, and training the diffusion model based on a first set of loss values associated with the first set of training output. The technique further includes generating, via execution of the diffusion model and a first adapter model, a second set of training output corresponding to a second set of 3D geometries based on a second set of conditioning inputs associated with a second conditioning mode, and training the first adapter model based on a second set of loss values associated with the second set of training output.

Methods, systems, and apparatus, including medium-encoded computer program products, for generating a three-dimensional mesh of an object, including: receiving a textual description of a target three-dimensional geometry specifying a curved surface of the object; generating a two-dimensional geometry image encoding the target three-dimensional geometry into a two-dimensional pixel array based on the textual description using a diffusion model, wherein each pixel of the two-dimensional pixel array represents a vertex of a plurality of vertices of a three-dimensional grid to be generated for the object; and generating a three-dimensional grid of the object based on the two-dimensional geometry image for rendering at a display of the physical device, where the three-dimensional grid includes a plurality of vertices defining a shape of the object, each vertex of the plurality of vertices having a corresponding position determined based on the two-dimensional geometry image.

In order to overcome the deficiency that the grid reinforced cylindrical shell structure created in the modeling analysis of the current grid reinforced cylindrical shell structure has a large difference with the actual structure, a universal parameterized three-dimensional geometric modeling method of the grid reinforced cylindrical shell structure containing material characteristics is provided.The reference coordinate system of the grid reinforced cylindrical shell structure is first created;secondly, the basic parameters required for constructing the grid reinforced cylindrical shell structure are determined, and the key parameters required for establishing the three-dimensional geometric model are solved;thirdly, based on the key parameters, the basic components such as the rib and the skin of the grid reinforced cylindrical shell structure are created through stretching, rotating and other methods;then, according to the position of each component in the grid reinforced cylindrical shell structure in the space coordinate system, the basic components are combined to establish the three-dimensional geometric model of the grid reinforced cylindrical shell structure;finally, the material properties of the skin, the rib and the weld are given, and the construction of the three-dimensional model of the grid reinforced cylindrical shell structure containing material characteristics is completed.

This invention belongs to the field of structural design and simulation testing technology for renewable energy equipment in the marine sector. It discloses a synchronous similarity design method and system for scaled-down towers. This method introduces an innovative composite penalty fitness function to drive a genetic algorithm for automatic optimization, thereby completing the segmented parameter design of the scaled-down tower in a single, high-precision manner. It synchronously ensures a high degree of similarity between the model and the actual model in key dynamic characteristics (first-order natural frequency) and accurate reproduction in three-dimensional geometry, while strictly complying with all engineering manufacturing constraints. This invention significantly improves optimization efficiency, achieves excellent design accuracy and completeness, and has strong engineering applicability.

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 aviation design, and provides a modeling method and system for a three-dimensional geometric model of an aviation wing structure, in the iterative optimization process of a spar, a rib and a stringer in an initial model, firstly, the offset is determined, then original grid vertexes in the model are expanded in the normal direction to generate a new vertex set, and the new vertex set is subjected to iterative optimization; an offset surface topological structure is reconstructed through triangulation, when the offset surface topological structure is reconstructed, the number of grid vertexes is adjusted according to the offset so as to achieve the purpose of improving the reconstruction quality of the model, when the coordinate average value after offset is larger than or equal to the coordinate average value of the original model, the number of the grid vertexes is increased, otherwise, the number of the grid vertexes is reduced, and the reconstruction quality of the model is improved. The purpose of improving the model reconstruction speed is achieved; on the basis of ensuring the modeling efficiency, the problem that the model precision is reduced after geometric reconstruction due to insufficient grid division proportion is solved.

The invention relates to the technical field of computer graphics, and discloses a cross-platform web end water body rendering implementation method which comprises the following steps: S1, collecting vertex data of a water body model, carrying out dynamic waveform simulation on the vertex data to generate a three-dimensional geometrical shape of a water surface, and in the dynamic waveform simulation process, carrying out dynamic waveform simulation on the vertex data to generate a three-dimensional geometrical shape of the water surface; extracting dynamic physical characteristics for the vertex in real time, wherein the dynamic physical characteristics comprise a waveform velocity vector and a waveform curvature; and S2, on the basis of the three-dimensional geometrical morphology of the water surface and the dynamic physical characteristics, calculating the color of the water body through an optical rendering model, and in the calculation process of the optical rendering model, dynamically adjusting the shoreside interaction effect according to the waveform velocity vector. According to the method, a linkage mechanism of physical characteristics and optical rendering and an adaptive performance optimization mechanism are constructed, so that cross-platform smooth operation is ensured, and meanwhile, a high-reality rendering effect of tight coupling of physical dynamic and optical performance of a water body is realized.

A computer-implemented method for measuring the three-dimensional geometry of a mineral glass-based glazing during or just after a temperature shaping operation. The method implements digital processing and calculations, based on the principles of stereocorrelation, of digital images of a random light pattern projected onto the surface of a transparent glazing. It makes it possible in particular to determine the shape or the three-dimensional geometry of a transparent glazing, the surface of which not be totally opacified and / or which radiates under the effect of temperature.

The invention relates to the field of modeling methods of finite element models, in particular to a modeling method of a steel structure combination node finite element model. The method comprises the following steps: firstly, preprocessing collected data to obtain preprocessed data; constructing an initial three-dimensional geometric model based on the preprocessed data; performing optimization based on the preprocessed data and the initial three-dimensional geometric model to obtain optimized geometric parameters; then, on the basis of the optimized geometric parameters, the preprocessed data and the initial three-dimensional geometric model, a steel structure combination precise node finite element initial model is output; and finally, on the basis of the steel structure combination accurate node finite element initial model, a nonlinear dynamic response updating formula is constructed, and equivalent stress is obtained. The technical problems that single parameter assignment neglects the stress synergistic effect of a node component, the modeling efficiency is low, the stress calculation error is large, and different section parameters and load working conditions cannot be accurately adapted are solved.

A method, system, and apparatus for computer-aided design and manufacture of a physical structure using hybrid additive and subtractive manufacturing, including media-encoded computer program products, includes, in one aspect, a method comprising: obtaining data on the 3D geometry of a part; simulating at least a portion of a manufacturing process, said at least a portion including adding a first material in a first stage and removing a second material in a second subsequent stage, wherein the second material comprises a portion of the first material, removing the second material includes mixing between the materials added in the first and second stages, and simulating the thermal effects of adding and removing materials in the first and second stages; and adjusting the amount of said portion based on the simulation results to prevent the part from deviating from its three-dimensional geometry, said deviation resulting in insufficient material available for mixing.

The invention discloses a method for evaluating the detection success rate of a foundation pile core drilling method, and the method comprises the steps: building a foundation pile core drilling method detection three-dimensional geometric model and a condition for judging whether the detection is successful or not through the core drilling method; and a Monte Carlo method is adopted by a computer to evaluate and solve the success rate of core drilling method detection under the given basic parameters of the foundation pile and the core drilling hole, and the relationship between the length-diameter ratio of the foundation pile and the success rate of core drilling method detection can also be solved. Therefore, the effect of guiding field detection is achieved, and if the success rate is evaluated to be low, the drilling offset of the core drilling hole can be reduced.

The invention relates to a finite element simulation grid-based reversible deformation design method and system for an investment casting. According to the method, a coordinate ID matching algorithm is utilized, a mapping relation is established between displacement data in an analyzed grid node displacement data file and corresponding nodes in an initial grid file, and an intermediate grid file containing casting deformation data is generated; by using a data mapping algorithm, reversely assigning the intermediate grid file to the initial grid file, and reconstructing to obtain a corrected grid file containing a reversible deformation feature; and finally, converting the corrected grid file into a three-dimensional geometric model as a reversible deformation design model for investment casting mold manufacturing. Compared with the prior art, the method has the advantages of simple process, high design precision and the like.

This invention discloses a multi-objective topology optimization method for aircraft design, belonging to the field of aerospace technology. The method includes: establishing a three-dimensional geometric model and defining the optimization region and aerodynamic preservation region; describing the structural boundary using level set functions; applying volume and manufacturing constraints with the objectives of maximizing stiffness and natural frequency; constructing a comprehensive objective function that minimizes the distance between ideal points using a compromise programming method; transforming the constraint problem using the augmented Lagrangian method; calculating shape sensitivity and deriving the normal velocity field; updating the level set functions to drive topology evolution; iterating until convergence to generate a Pareto front solution set; selecting the optimal solution and reconstructing it into a manufacturable three-dimensional model. This invention solves the multi-objective collaborative optimization problem while preserving the aerodynamic shape, resulting in clear boundaries, strong manufacturability, and significantly improved structural performance and engineering applicability.

The present invention discloses a 3D scene reconstruction method, device, electronic device and readable storage medium, which are applied to the technical field of 3D reconstruction. In order to solve the problem of low accuracy of existing 3D reconstruction, it is proposed to update a current 3D geometric model based on a current frame image to obtain an updated 3D geometric model; use a brightness map obtained based on the current frame image to update the existing texture image stored inside the surface voxels in the updated 3D geometric model to obtain an updated texture image; judge whether the current frame image is the last frame image, and if so, use the updated 3D geometric model as the reconstructed 3D geometric model, and use the updated texture image corresponding to each surface voxel as the reconstructed texture image to constitute a reconstructed 3D scene; otherwise, use the next frame image as the current frame image and return to execute the step of updating the current 3D geometric model based on the current frame image; the accuracy and quality of reconstruction can be improved.