21 results about "Central line" patented technology

A road center line determination method, device, equipment and storage medium are disclosed. The method comprises: acquiring a first boundary contour line and a second boundary contour line on both sides of a target road; determining an outer bounding rectangle of the boundary contour line and a projection point of each boundary point on the outer bounding rectangle; extending a connecting line between each boundary point and the corresponding projection point, determining a first associated point intersecting the contour line, and taking a midpoint between each boundary point and the corresponding associated point as a feature point corresponding to the boundary point; based on the change direction of the boundary contour line, sorting each first feature point and each second feature point, and based on the sorted feature point sequence, determining a center line corresponding to the target road. Through the technical scheme of the embodiment of the present application, the determination efficiency and accuracy of the road center line can be improved, and the combined center line can perfectly retain the geometric shape of the original two lines.

The present application belongs to the field of mechanical design, and particularly relates to a method for extracting a center line of a rod body based on internal point array information of a three-dimensional model. The method comprises the following steps: S1, extracting an outer surface and a bounding box information of a rod body model with a cross-sectional radius R of the rod body; S2, generating an initial point array in the bounding box; S3, extracting a point inside the rod body model and a nearest point of the point to the outer surface of the rod body model; S4, calculating coordinates of a center O of a rod body cross section corresponding to each point in a point array sub-set extracted in step S3; and S5, performing curve fitting on all points O to obtain a center line of the rod body model. The present application can realize fast extraction of a center line of a non-straight rod body three-dimensional model, and is particularly suitable for application in a rod body design environment with a relatively complex shape.

The invention provides an airway geometric parameter measurement method and system, and relates to the technical field of medical image processing, and the method comprises the steps: obtaining airway foreground voxel data corresponding to a chest CT, and converting a voxel index coordinate into a world physical coordinate according to image space meta-information; obtaining a center line point set through three-dimensional skeletonization, establishing candidate connecting edges in a preset neighborhood, generating a topological tree based on a strategy with branch penalty terms, and completing branch segmentation and generation coding; the method comprises the steps that firstly, a tail end branch meeting a preset condition serves as a starting point for backtracking, the section area and the section equivalent diameter of each node slice are calculated, branch node direction vector score cross angle parameters are fitted, finally, a structured file is summarized and output according to algebraic labels and other dimensions, and stable measurement and standardized output of airway multi-scale geometric parameters can be achieved. And the comparability and repeatability of group scale analysis are improved.

The application discloses a center line to inner hole bottom surface vertical distance gauge for a reducer shell bearing hole, which comprises a base unit, a calibration unit, an auxiliary unit and a measuring unit; the measuring unit comprises a measuring table and a table seat for mounting the measuring table; the calibration unit comprises a calibration piece arranged on the plane of the base unit, and the height of the calibration piece is designed as the standard vertical distance between the lowest point of the bearing hole and the inner hole bottom surface minus the radius of the bearing hole; the auxiliary unit comprises an auxiliary base, and the calibration part of the auxiliary base is tightly attached to the plane of the base unit; the table seat is arranged on the auxiliary base; the mechanical reference conversion of the calibration piece and the auxiliary base converts the complex three-dimensional space measurement into simple height difference comparison, the single measurement time is greatly shortened, the efficiency is improved compared with the traditional three-coordinate measurement, the cost of the gauge is reduced, the enterprise cost is significantly reduced, and the operation is simple, so that workers can quickly and simply start and complete standardized detection.

The invention provides an automatic calculation method for a rail transit shield interval evacuation platform, and the method comprises the steps: opening a plane design scheme file after an AutoCAD secondary development program is operated, and reading road design scheme data and tunnel inner diameter data; the method comprises the following steps: inputting and storing a rail transit shield interval tunnel rail ultrahigh value, a rail structure height, a center line offset and a corresponding mileage range, setting design parameters of an evacuation platform, determining a platform design range, segmenting the evacuation platform, and calculating the distance between the outer side of the evacuation platform and a line center line in a segmented manner; calculating the clear distance from the center line of the shield interval tunnel line to the evacuation platform, and determining the width of the evacuation platform; the digital and intelligent level is greatly improved, the data accuracy is 100%, and compared with a traditional manual calculation mode, the calculation efficiency and the calculation precision are greatly improved.

The application discloses a complex conduit first-order continuous center line reconstruction method based on scanning point cloud data and belongs to the field of engine geometric parameter digitization detection. After obtaining scanning point cloud data of an outer surface of a conduit, straight pipe data and curved pipe data of the complex conduit are segmented. For the segmented straight pipe and curved pipe data, random sampling cylinder fitting and circle fitting operation based on intersection of a vector point and a main plane are respectively performed to obtain trend lines of the straight pipe and the curved pipe. For the trend lines of the straight pipe and the curved pipe, center points of different pipe sections based on equally-spaced vertical section planes are solved, and linear fitting is respectively performed on the center points of the different pipe sections to obtain a plurality of discontinuous center line sections of the complex conduit. A cubic spline curve is adopted to perform first-order derivative interpolation fitting between adjacent straight line sections and circular arc section center lines to obtain a complex conduit first-order derivative continuous center line. The reconstructed center line is used as a reference for calibration of a pipe special-purpose measuring device measuring capacity.

This invention relates to a rapid method for determining conical field-of-view occlusion, comprising: S1, setting Δ blk Let the occlusion triangle be represented by its three vertices A, B, and C, and the center line of the conical field of view. Determine the occlusion triangle Δ. blk Does the plane S containing the antenna reflector aperture intersect with the conical field of view? If they intersect, then the Δ on the upper part of plane S... blk Divided into (Δ blk )1、(Δ blk S2; Determine whether it is consistent with (Δ) blk S1. Intersect; S3. Determine if any of A, B, and C is inside the conical field of view; S4. Determine Δ blk Does there exist an edge that intersects the conical field of view? S5, If (Δ blk If 2 is not empty, then for (Δ) blk 2. Repeat steps S2 to S4; traverse the triangular mesh of all obstructions; traverse the azimuth of all conical fields of view to determine the azimuth of the obstructed conical fields of view. This invention enables rapid and quantitative calculation of the spatial distribution of the azimuth of a two-axis rotatable point beam antenna when it is obstructed by a star.

The application discloses a tunnel three-dimensional center line extraction method based on octree occupancy map and distance transformation, which takes tunnel scene point cloud sequences registered to the same global coordinate system as input, incrementally constructs a global octree occupancy map to obtain an occupancy leaf voxel center point set, extracts a candidate occupancy voxel center point set and performs three-dimensional principal component analysis to obtain a stable axial direction, constructs a cross-section plane along the stable axial direction, extracts a point set within the slice thickness range, projects the point set to a two-dimensional coordinate system, rasterizes a cross-section obstacle grid, performs two-dimensional distance transformation, takes a point corresponding to a maximum value of a distance field as a maximum inscribed circle center, and back-projects the point to obtain a slice center point and a clear radius, accumulates continuous effective center points, applies a maximum turning angle constraint, and outputs a tunnel three-dimensional center line. The application does not require strict alignment of the input tunnel coordinate system Z-axis with the gravity direction, and does not depend on an odometer trajectory or a platform attitude estimation axial direction, and is suitable for straight or curved tunnel structures with longitudinal slopes.

The application discloses a shot specimen deformation analysis method, device, equipment and storage medium. The principal component analysis of point cloud data can determine the geometric center, major axis, minor axis and minor axis, automatically adapt the specimen placing posture and eliminate the influence caused by the position deviation. The point cloud projection based on the feature data can simplify the three-dimensional data into two-dimensional data, reduce the subsequent processing complexity while retaining the key deformation features. The preprocessing of the projected point cloud can improve the point cloud continuity, eliminate noise and void, generate a clear and stable optimized image, and ensure the accuracy of the subsequent center line extraction. The extraction of the center line corresponding to the optimized image and the back projection can obtain an accurate and continuous three-dimensional center line point cloud, avoiding the deviation caused by manual intervention. The deformation analysis of the shot specimen based on the center line point cloud can realize the accurate calculation of the curvature and the equivalent arc height and the automatic verification of the simulation model, and comprehensively improves the reliability and efficiency of the deformation evaluation.

This application provides a method, apparatus, equipment, and medium for extracting the centerline of an irregular cross-section tunnel structure, relating to the field of tunnel structure construction and inspection technology. The method includes: obtaining three-dimensional point cloud data of the tunnel; obtaining two-dimensional point cloud data based on the three-dimensional point cloud data; clustering the two-dimensional point cloud data to obtain a two-dimensional centerline point set; horizontally segmenting the three-dimensional point cloud data based on the two-dimensional centerline point set to obtain a cross-sectional point cloud dataset between two adjacent center points in the two-dimensional centerline point set; obtaining a top arch centerline point set and a bottom slab centerline point set based on the cross-sectional point cloud dataset and the two-dimensional centerline point set; and obtaining a three-dimensional central axis point set of the tunnel based on the top arch centerline point set and the bottom slab centerline point set. The method of this application can more effectively utilize the three-dimensional data of the tunnel, thereby accurately extracting the centerline of an irregular cross-section tunnel.

A frame which is a frame having a rectangular shape in plan view, four intersection points at which center lines of the length directions of the respective side portions of the frame intersect with each other are provided at four corner portions of the frame, the frame is arranged on a flat surface, a height Z1 from the flat surface is measured at the four intersection points, a first intermediate point which is an intermediate point of two intersection points among the four intersection points that are located on the same side portion of the frame, a second intermediate point which is an intermediate point of the intersection points and the first intermediate point, and a difference between a maximum value and a minimum value of the heights Z1 of the intersection points is 25 µm or less when a point among the four intersection points, the first intermediate point, and the second intermediate point at which the height Z1 is the smallest is set as a reference point (zero).

The application relates to a kind of section measurement and data processing method and device of quasi-rectangular shield tunnel, belong to the technical field of shield tunnel construction measurement, method includes: obtaining the design parameter of quasi-rectangular shield tunnel section to be measured;Receive total station at the position of section to be measured, at least three measuring points of the actual pipe wall of small circular arc and collect three-dimensional coordinates;Based on the three-dimensional coordinates of all measuring points, solve the measured radius and measured center coordinates of small circular arc at the section to be measured by applying space circle fitting algorithm calculation;For each target measuring point, according to measured center coordinates, measured radius, design track surface elevation and the elevation difference between target measuring point and design track surface, the horizontal distance measured value of target measuring point relative to design line center line is calculated by using the geometric characteristics of small circular arc;Based on the horizontal distance measured value and design horizontal distance value of each target measuring point, the data processing of section to be measured is completed.The application has the effect of improving the measurement accuracy and operation efficiency.

The application provides a waterway boundary and center line mining method and system for AIS ship trajectory big data, and comprises the following steps: S1, carrying out Delaunay triangulation on the track points of the AIS ship trajectory data, and screening the triangles in the track point triangulation to obtain the original boundary of the track points; S2, carrying out smoothing processing on the obtained original boundary of the track points, further carrying out Delaunay triangulation on the vertex point set of the original boundary of the track points after the smoothing processing, and screening the vertex point set triangulation to obtain the waterway contour; and S3, constructing the waterway graph and the center line of the waterway based on the waterway contour.

The invention discloses a method for automatically extracting geometric information of a tubular three-dimensional model. Establishing a reference plane and a rotating center shaft by searching a key curved surface of the tubular three-dimensional model; key points are created through intersection points between all the reference planes and all the rotating center shafts, and sorting is managed according to rules; solving the bending radius through any one bending surface; and finally, geometric information of the tubular three-dimensional model is obtained through the steps, the pipe diameter is obtained, and the center line of the tubular three-dimensional model is created. According to the method, the topological geometric information of the tubular three-dimensional model is extracted, so that related work of automation of the tubular three-dimensional model can be developed.

The application provides a kind of broken line tunnel high-precision control underbreak measurement method, steps are as follows: (1) respectively determine the start and end mileage points of S1, S2 section turning and S2, S3 section turning of tunnel; (2) for each section of tunnel, according to the corresponding tunnel edge line, respectively determine the left side tunnel calculation center line and the right side tunnel calculation center line; (3) according to the tunnel section corresponding to the original tunnel center line of the section of tunnel, respectively determine the left and right sides of the calculation center line belonging to the section; (4) calculate the three-dimensional coordinates of any tunnel contour point within two sections of mileage through the calculation center line and the section belonging to it; (5) through the three-dimensional coordinates of any contour point at the corresponding mileage, loft the contour to the tunnel excavation face, and excavate according to the lofting point position. The application accurately calculates the tunnel contour coordinates at the turning point of broken line tunnel by simulating the tunnel "calculation center line", improves the measurement accuracy, ensures the tunnel limit requirement, and improves the work efficiency.

The embodiment of the invention discloses a method for constructing a topology description function, which comprises a first function and a second function, wherein the first function takes the parameter coordinate as a variable and is used for determining a point which corresponds to the parameter coordinate and is used for determining a spline assembly center line of the variable thickness spline assembly in a preset design domain and a first coordinate in a world coordinate system, and the second function takes the parameter coordinate as a variable and is used for determining the thickness of the variable thickness spline assembly at the parameter coordinate; the first function and the second function are continuous differentiable mathematical operation functions; constructing a third function according to the first function and the second function; and constructing a topology description function according to the third function. A global continuous differentiable topology description function is constructed through the combination of a first function, a second function and a third function which are continuously differentiable, and the topology description function can promote the application of the topology description function in gradient-based topology optimization and can improve the effectiveness of optimization.

A method, apparatus, medium, and product for extracting geometric features of a structure are disclosed, relating to the field of data processing. In this method, inclined aerial survey model data of the structure to be processed is acquired, and an irregular triangular network (ITN) is constructed based on the inclined aerial survey model data. Based on the topological relationship of the ITN, boundary points are extracted and organized in a preset order to obtain an initial boundary point sequence of the structure. The initial boundary point sequence is simplified and extracted to obtain a simplified boundary point sequence, and the simplified boundary point sequence is adjusted and fitted to obtain the outer boundary model of the structure. Based on the outer boundary model, the centerline and center point of the structure are calculated. Implementing the technical solution provided in this application improves the accuracy of geometric feature extraction.

This invention provides a method for creating a multibody dynamics leaf spring model. First, the radius R of the front arc curve of the leaf spring is measured. f , arc included angle A f The radius of curvature R of the rear circular arc curve r , arc included angle A r And create these four parameter variables; then randomly create 22 coordinate reference points f0, f1...f on the leaf spring. 10 r0, r1...r 10 Select reference points f0 and r0 as the base points; then modify the reference point f. N and r N The coordinates are determined; after modification, the spring width is input using reference points and dynamics software to create a component with a small mass block; and the coil lug and swing lug are created to complete the single-piece leaf spring modeling. This invention's leaf spring model creation method uses geometric center lines and sine and inverse sine function theory to model from point to point, and then from point to solid. No additional plugins are needed during the modeling process, effectively reducing modeling costs and increasing efficiency. Modeling only once and can be applied to various leaf spring models by changing the parameters, making it highly practical.

The invention discloses a measurement system, a measurement method and reference devices for fixed stretch reduction equipment, and relates to the technical field of measurement, and the measurement system comprises two reference devices which are fixedly installed on the outer sides of a head lower sliding plate and a tail lower sliding plate of a fixed stretch reduction machine respectively; each reference device comprises a stand column connected with the lower sliding plate and a reference block arranged at the top end of the stand column, each reference block is provided with a horizontal center line positioning face serving as a rolling center line adjusting reference and an elevation positioning face serving as an elevation adjusting reference, and the horizontal center line positioning faces of the two reference devices are used for jointly defining a reference straight line. By measuring the relative position of the component of the fixed tension reduction mill and the reference straight line and combining installation data of the reference device, the abrasion loss or the deviation value of the component is calculated, the problem of rapid measurement or adjustment of a center line during daily maintenance or failure of the fixed tension reduction mill is solved, the deviation value of the positioning block of the fixed tension reduction mill can be rapidly and accurately measured, and the working efficiency is improved. And the measurement requirements of the fixed tension reducing mill in different maintenance scenes are met.

The invention relates to the field of aircraft air inlet system design modeling, and discloses a variable-curvature air inlet diffusion section fairing design method and system.The method comprises the steps that the center line of an air inlet diffusion section is constructed to obtain a continuous center line, sections are defined in the axial direction of the continuous center line, and all the sections are distributed in the normal direction of the center line to form a section family; determining complex characteristics of the section family; constructing a middle section contour to obtain a plurality of initial section contour point sets, performing Fourier transform on each point set, converting the point sets into section contour frequency data represented by a frequency domain, and applying low-pass filtering operation; inverse Fourier transform is carried out on the filtered section contour frequency data to obtain a section contour point set; the section contour point set is arranged according to the center line to construct the geometric shape of the three-dimensional diffusion section, and a standard file format capable of being used for modeling and simulation is exported. The method solves the technical problems of discontinuous section transition, sudden curvature change, remarkable high-frequency disturbance and no design control parameters in the geometric design of the diffusion section of the existing air inlet channel.

The invention discloses a road stake mark measurement and calibration method using three-dimensional reconstruction, relates to the technical field of measurement and calibration, and is used for solving the problems that the existing process has multiple weak links: mileage indexes near version boundaries are inconsistent; the mapping stability is insufficient due to sparse cross-version anchor points or poor quality; performing space-time alignment on a three-dimensional reconstruction center line, a pile card OCR, a GNSS and course observation under a unified arc length coordinate system, and introducing a time dimension constraint by using a version validity period and a cross-version anchor point to ensure that the cross-version mileage is continuous; an HMM sequence containing version switching penalty is adopted for decoding, and mutual exclusion candidates are eliminated in cooperation with a conflict graph maximum weight consistent set; stable confidence distribution is given when geometry / text / positioning is inconsistent through DS evidence fusion, backflow is triggered through the conflict degree and posterior entropy, local densification, template switching and weight reestimation are executed, and the robustness of the degradation working condition is improved; regularization and time sequence consistency combined constraint is set for kilometer transition, and jump is restrained.