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1028 results about "Surface fitting" patented technology

Method for optimizing WLAN (Wireless Local Area Network) indoor ANN (Artificial Neural Network) positioning based on FCM (fuzzy C-mean) and least-squares curve surface fitting methods

The invention discloses a method for optimizing WLAN (Wireless Local Area Network) indoor ANN (Artificial Neural Network) positioning based on FCM (fuzzy C-means) and least-squares curve surface fitting methods, relating to an indoor positioning method used for indoor positioning and aiming to solve generalization capability reduction of an ANN system caused by singular reference points existing in a training sample space. The method comprises the following steps of carrying out clustering on pre-labeled reference points based on the FCM method to confirm corresponding clustering centers and membership degree of different reference points to clustering centers thereof; obtaining the space position of the singular reference points in a target positioning area on the basis of carrying out quantitative processing and similarity calculation on the membership degree of the reference points; updating positioning fingerprint database by utilizing the least-squares curve surface fitting method to reject abrupt change points in an intensity distribution chart; estimating the cluster of a terminal on the basis of calculating the Euclidean distance between signal intensity samples collected online and different clustering centers; and finally accurately estimating the terminal by utilizing corresponding ANN subsystems.
Owner:HARBIN INST OF TECH

Construction method of three-dimensional geologic model

ActiveCN102750739AEnables direct 3D interpretation analysisQuick response3D modellingSurface fittingWorkload
The invention relates to a three-dimensional modeling technology and discloses a construction method of a three-dimensional geologic model. The construction method solves the problem that massive auxiliary two-dimensional analysis must be carried out when the three-dimensional geologic model is built traditionally, so that during the modeling process, the workload is large, a modeling process is complex and the model cannot be automatically updated. According to the construction method, direct three-dimensional interpretation analysis of geological information is achieved in a dynamically and controllably adjusted surface fitting (interpolation) mode, and two-dimensional analysis results are no longer essential bases; an engineering geological base information database closely combined with production practice is established, and collecting work of geological base information and information storage management are carried out on the basis of three-dimensional analysis interpretation; the base information is continuously enriched and perfected along with a production schedule and can be rapidly reflected to the analysis and adjusting process of the three-dimensional geologic model; and three-dimensional direct output or two-dimensional sectioning output of geologic results is correlated with the engineering geological database, and normalized automatic output is formed. The construction method is suitable for three-dimensional modeling for geology.
Owner:POWERCHINA CHENGDU ENG

Method for creating three-dimensional surface model by using perspective sketch

The invention discloses a method for creating a three-dimensional surface model by using a perspective sketch. The method comprises the following steps of: identifying and processing a hand-drawn sketch into a vertex-edge graph consisting of contour sides and articulation points, and identifying closed areas; identifying the symmetric relation of the three-dimensional surface model, and completing hidden contours for the contours according to symmetry and visibility; establishing an object coordinate system of the surface model according to a symmetrical relation, calculating three-dimensional coordinates of the contour sides and the articulation points of the surface model, and recovering the coordinates of three-dimensional space curves among the articulation points according to curve projection between the three-dimensional coordinates of the articulation points and the articulation points; categorizing the three-dimensional closed areas of the model into different closed area pieces according to the characteristics of a level modeling method and a B-spline surface fitting method; and modeling the closed area pieces into sub-surfaces according to the characteristics of the closed area pieces by the level modeling method or the B-spline surface fitting method and jointing the sub-surfaces into a three-dimensional model through dispersing, blending and splicing.
Owner:NANJING UNIV

Actually measured data-based spacecraft component assembly simulation method

The invention discloses an actually measured data-based spacecraft component assembly simulation method. The assembly simulation method includes the following steps that a parametrized three-dimensional rapid modeling method is utilized to generate actually measured dimension-based three-dimensional small component models after final assembly inspection personnel actually measure and input the dimensions of key small component interfaces into a corresponding parametrized three-dimensional modeling system; a reverse point cloud curved surface fitting method is utilized to convert the surface shapes of real objects of large key components into discrete geometric coordinate points, and on the basis, the modeling of complex curved surfaces is carried out, so that reverse three-dimensional digitalized models of the large key components are formed; the assembly process is simulated and analyzed; ergonomics is simulated and evaluated. By combining a virtual reality scene with reverse real object modeling, the actually measured data-based spacecraft component assembly simulation method disclosed by the invention detects interference points and risk sources in advance to find out assembly incoordination and other problems, thus increasing the reliability of the final spacecraft assembly process and the efficiency of final assembly.
Owner:BEIJING INST OF SPACECRAFT ENVIRONMENT ENG

Three-dimensional geological modeling method and device

The invention discloses a three-dimensional geological modeling method and device, relates to the field of geological modeling, overcomes primary shortcomings of an existing integral approach, combines advantages of a local method and can quickly establish a multilayer complex geological body through the utilization of geological original data. The three-dimensional geological modeling method mainly comprises obtaining fault control data from collected geological data, utilizing a stratum inversion method to fit a fault surface, setting fault lofting parameters for the fault surface, and establishing a planar three-dimensional fault; utilizing the stratum inversion method to establish three-dimensional geological body blocks containing different strata, and performing overall surface fitting operation on the post-inversion three-dimensional geological body blocks to obtain a three-dimensional geological body; performing stratum forward modeling on the established three-dimensional geological body by utilizing the fault control data and the planar three-dimensional fault and dividing the three-dimensional geological body into different three-dimensional geological body blocks; assembling the divided three-dimensional geological body blocks to form an integrated fault-contained three-dimensional geological body. The three-dimensional geological modeling method and device is mainly applicable to three-dimensional modeling of fault display.
Owner:INST OF GEOLOGY & GEOPHYSICS CHINESE ACAD OF SCI

Three-dimensional measurement method and device based on linear structured light

The invention relates to a three-dimensional measurement method based on linear structured light. The three-dimensional measurement method comprises the following steps of: 1, arranging a plane with marking points and marking lines as a target, and vertically placing the plane on a turntable; 2, regulating a laser and a camera, and setting the center of the turntable as an original point of a world coordinate system; 3, continuously shooting the marking points; 4, determining a world coordinate and an image coordinate of each marking point; 5, determining a camera model; 6, scanning a workpiece to be measured; 7, obtaining a two-dimensional image coordinate of a central point of a scanning light bar; 8, calculating a corresponding three-dimensional world system coordinate by using the two-dimensional image coordinate of the central point of the scanning light bar according to the determined camera model, and acquiring point cloud data of the workpiece; and 9, preprocessing the point cloud data and introducing the point cloud data into reverse engineering software, and finishing reestablishment of a workpiece geometric model by curved surface fitting. By the method, the precision requirement on the camera is low; the method is simple; the requirement on camera calibration can be met well; and the method is higher in precision.
Owner:SHENYANG AIRCRAFT CORP +1

Flexible stretch-forming device and method for carrying out stretch-forming on plate by utilizing same

The invention discloses a flexible stretch-forming device and a method for carrying out stretch-forming on a plate by utilizing the flexible stretch-forming device and solves the technical problem that the stretch-forming accuracy of a flexible stretch-forming device for the molded surface of a reconfigurable unidirectional continuous die is low. The technical scheme includes that the flexible stretch-forming device comprises an industrial manipulator, a heating forming head, a power supply, a multipoint die, a nail post and a polyurethane elastic cushion. The nail post is mounted on the base of the multipoint die, the polyurethane elastic cushion is positioned above the nail post, the lower surface of the polyurethane elastic cushion is attached to the discrete surface formed by the nail head of the nail post, the plate is positioned above the polyurethane elastic cushion, the lower surface of the plate is attached to the upper surface of the polyurethane elastic cushion, the heating forming head is positioned above the plate, and the spherical head surface of the heating forming head is contacted with the upper surface of the plate. According to the flexible stretch-forming device and the method for carrying out stretch-forming on the plate by utilizing the flexible stretch-forming device, the electromagnetic induction heating forming head is adopted to locally heat the plate in the stretch-forming process, the local heat effect of the region can reduce the deformation resistance of the plate, the plasticity is improved, the resilience value is reduced, and the forming accuracy of the plate is improved.
Owner:NORTHWESTERN POLYTECHNICAL UNIV

Fibular flap repairing mandible defect operation guiding template and manufacturing method

The invention discloses a manufacturing method for a fibular flap repairing mandible defect operation guiding template. The manufacturing method for the fibular flap repairing mandible defect operation guiding template comprises the steps that a mandible three-dimensional model and a fibula three-dimensional model are rebuilt, a lesion area is determined, and the target fibula is determined; the lesion area is excised, and a jaw non-lesion area model and a lesion area model are saved; the inner surface of a jaw cutting locating guiding template is attached to the outer surface of the lesion area model; the area where the fibula three-dimensional model and fibula subsection models are placed is partitioned to form a fibula repairing area; the inner surface of a fibula molding guiding template is entirely attached to the cheek side surface of the fibula repairing area; the inner surface of a fibula cutting locating guiding template is entirely attached to the outer surface of the corresponding fibula subsection model; the jaw cutting locating guiding template, the fibula molding guiding template and the fibula cutting locating guiding template are molded. The fibular flap repairing mandible defect operation guiding template and the manufacturing method have the advantages that the bone cutting scheme of the fibula and the molding position of each section of the fibula can be accurately controlled, the precise implement of a fibular flap transplanting repairing mandible defect operation is guaranteed, the operation time is shortened for the fibular flap repairing mandible defect operation.
Owner:6D DENTAL TECH

Detection method of checkboard grid image angular point sub pixel

The invention provides a detection method of a checkboard grid image angular point sub pixel. The detection method of the checkboard grid image angular point sub pixel comprises the steps that 1, a checkboard grid calibration template is filmed trough a camera, a template image of the checkboard grid calibration template is obtained, and binaryzation is conducted on the template image to obtain a binaryzation image; 2, traversal is conducted on the binaryzation image through a circular template, and screening is conducted on all the tested pixel points of the binaryzation image to screen out candidate angular points; 3, according to the character of the candidate angular points that the candidate angular points are symmetrically arranged near a true angular point which is determined by an angular point set, the abscissa average value and the ordinate average value of the pixel positions of the candidate angular points are calculated, and the abscissa average value and the ordinate average value serve as the sub pixel coordinates of the true angular point. According to the detection method of the checkboard grid image angular point sub pixel, only simple arithmetic is needed, and operations of differential, interpolation, surface fitting and the like are not needed, so that the detection process is simple and easy to realize, sub pixel level precision can be directly obtained, and good detection precision and real-time are obtained.
Owner:UNIV OF SHANGHAI FOR SCI & TECH

Method of analyzing spot welded structures

Method of analyzing spot welded sheet metal structures subjected to forces that promote one or more basic failure modes of either shear tension, in-plane rotation, coach peel, normal tension, or any combination of such basic modes, the method comprising: (i) providing spot welded sheet metal test coupons for analysis of the selected failure mode for the structure to be analyzed and subjecting such test coupons to progressively increasing forces that eventually achieve failure in the selected failure mode to thereby generate measured load and displacement test data; (ii) analyzing the data from the basic modes to derive and extract spot weld strength and stiffness information and then surface fitting such extracted data to create a database; (iii) establishing a computer math model for simulating the spot weld failure modes of the structure and populating the database thereinto to enable simulated physical tests of the structure; (iv) creating a cumulative-damage failure criterion for the spot welded structure that ratios (a) the resultant strength information from the populated math model for selected combinations of load and selected combinations of time and structure thickness, and (b) the measured strength information derived for such combinations of load derived from the test data; and (v) solving the criterion to determine whether it indicates failure for the combination of resultant strength and other values selected.
Owner:FORD GLOBAL TECH LLC

Image sub-pixel edge extraction method having extensive adaptability

The invention discloses an image sub-pixel edge extraction method having extensive adaptability, comprising steps of adopting an adaptive high-low threshold value calculation method, executing a local maximum central value choosing operation on a gradient image by combining with gradient direction information of a pixel point after obtaining a gradient image, establishing a relative coordinate with a random pixel point as an origin point, taking eight-neighborhood pixels around the origin point as local maximum central value choosing data samples, obtaining a comparison result between the adjacent neighborhoods according to a gradient direction, determining whether the current pixel position is a boundary point candidate position, adopting a Hessian matrix method based on a Steger surface fitting method to solve a sub-pixel position of the boundary point and connecting boundary points for forming a line to constitute a set of directed continuity points. Determination whether an extreme value of a local gradient magnitude is a boundary point can be made by combining with a specific threshold value; if the local extreme value is greater than a given threshold value, the local extreme value is marked as a boundary point, and if the local extreme value is smaller than a given threshold value, the local extreme value is a noise point or a background point The invention has great instantaneity.
Owner:BOZHON PRECISION IND TECH CO LTD

Bulging die for titanium-alloy thin-walled complicated irregular annular workpieces

The invention relates to a bulging die for titanium-alloy thin-walled complicated irregular annular workpieces. The bulging die comprises a core shaft, n brackets, n male dies, female dies and a base, wherein n sliding rails are uniformly distributed on the upper surface of the base, and all brackets are respectively embedded in all the sliding rails so as to form a circular assembly; the small-diameter end of the core shaft is located in the assembly and is fit with the internal surfaces of all the brackets; the n male dies are fixedly arranged on all the brackets respectively; each circular female die is formed through folding corresponding two semicircular female die clacks and sleeves the external surface of the corresponding male die; the internal surfaces of the female dies and the external surfaces of the male dies are workpiece forming faces. According to the bulging die, the forming of the irregular annular workpieces mainly relies on the plastic forming of a material, so that the surface wear resistance of parts is improved, the service lives of the parts are prolonged, and the material is saved; the accuracy of the annular workpieces can be corrected; during continuous repeated machining, the consistency of size and accuracy of the parts can be guaranteed.
Owner:丹东丰能工业股份有限公司

Ultraprecise turning method of optical lens with incline

ActiveCN102078968AReduce relief angleAvoid interferenceEngineeringMachine tool
The invention belongs to the technical field of manufacture and ultraprecise processing of optical elements, and relates to an ultraprecise turning method of an optical lens with an incline, which comprises the steps of: taking two datum points on the incline, determining a workpiece initial plane, roughly processing on the incline to be processed; making a fixture and assembling the workpiece on the end face of a processing lathe, regulating the workpiece initial plane to be vertical to the z axis, regulating a workpiece center to be coincide with a main shaft center; and carrying out coordinate conversion to obtain a connecting line of two end points to be coincide with the x axis, calculating a normal angle of the whole curved surface with center coordinates of the two datum points as a new curved surface of the original point, determining a diamond tool rear angle required by processing the curved surface, selecting a proper tool to be assembled on the lathe, carrying out NURBS (Non-Uniform Rational B-Spline) curved surface fitting on the curved surface subjected to the coordinate conversion, and determining the processing path according to a spiral drive line method. The lens surface is leveled by the coordinate conversion, and the tool rear angle required by processing the curved surface is reduced, thus the processing efficiency and the size of the processing workpiece can be increased, and the method is suitable for processing the large-incline optical lens with any gradient and Sag value.
Owner:TIANJIN UNIV

Rapid quality inspection method for steel structure based on three-dimensional scanning technology

PendingCN110095060ASolve working hoursSolve the costUsing optical meansPoint cloud3d scanning
The invention, which belongs to the technical field of building construction, discloses a rapid quality inspection method for the steel structure based on a three-dimensional scanning technology. Themethod comprises the following steps: step one, performing rapid scanning; to be specific, scanning a component lifting unit rapidly by using a high-precision full-station scanner to obtain point cloud data of the component lifting unit; step two, performing feature point coordinate calculation; to be specific, carrying out plane and cylindrical surface fitting by the point cloud data, establishing plane and cylindrical surface equations, and calculating three-dimensional coordinates of feature point locations; and step three, performing the quality analysis; to be specific, calculating and analyzing the three-dimensional coordinates of feature point locations to obtain three-dimensional coordinates of feature points of the component lifting unit in a construction coordinate system and a design coordinate system, calculating errors of three directions, and determining the splicing quality. According to the invention, plane and cylinder fitting, three-dimensional coordinate calculationof key point locations, and three-dimensional coordinate transformation are carried out to obtain the three-dimensional coordinates of rod nodes of the lifting unit in the design coordinate system; and the component quality of the lifting unit is evaluated based on the coordinate difference of three directions.
Owner:NO 1 CONSTR ENG CO LTD OF CHINA CONSTR THIRD ENG BUREAU CO LTD
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