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314 results about "Plane fitting" patented technology

Plane fit. Given a set of points (3D) this function computes the plane that fits best those points by minimizing the sum of the quadratic distances (perpendicular to the plane) between the plane and the points. The fit is performed by computing the eigen-values/vectors associated to the distribution of points.

Fusion calibration method of three-dimensional laser radar and binocular visible light sensor

The invention discloses a fusion calibration method of a three-dimensional laser radar and a binocular visible light sensor. According to the invention, the laser radar and the binocular visible lightsensor are used to obtain the three-dimensional coordinates of the plane vertex of the square calibration plate, and then registration is carried out to obtain the conversion relation of the two coordinate systems. In the calibration process, an RANSAC algorithm is adopted to carry out plane fitting on the point cloud of the calibration plate, and the point cloud is projected to a fitting plane,so that the influence of measurement errors on vertex coordinate calculation is reduced. For the binocular camera, the vertex of the calibration plate is obtained by adopting an angular point diagonalfitting method; for the laser radar, a distance difference statistical method is adopted to judge boundary points of the point cloud on the calibration board. By utilizing the obtained vertex coordinates of the calibration plate, fusion calibration can be accurately carried out on the three-dimensional laser radar and the binocular visible light sensor, a rotation matrix and a translation vectorof coordinate systems of the three-dimensional laser radar and the binocular visible light sensor are obtained, and a foundation is laid for realizing data fusion of three-dimensional point cloud anda two-dimensional visible light image.
Owner:BEIHANG UNIV

Method for overall calibration of galvanometer type line laser scanning three-dimensional measuring system

ActiveCN107014312AReduce the impactFlexible calibration schemeUsing optical meansLaser scanningGalvanometer
The invention discloses a method for overall calibration of a galvanometer type line laser scanning three-dimensional measuring system. First two lenses whose effective focal lengths are f1 and f2 are selected, and a camera is utilized to shoot a plane target and feature point coordinates are extracted, and main point coordinates of an image are calculated according to a varifocal method; then the lens whose focal length is f1 is used as a lens of the system, and for the feature point coordinates on the plane target which are obtained by the lens, intrinsic parameters and extrinsic parameters of the camera are calibrated; next, by changing galvanometer control voltage and driving a one-dimensional translation table to move, line laser stripes in different depth directions and different optical planes are obtained, and through operation of plane fitting and intersecting line obtaining, a transformation relation between a target coordinate system and a world coordinate system is obtained; and finally, coordinates under a system model are all unified to an image pixel coordinate system and the world coordinate system, thereby completing calibration of the whole system. The method has the advantages of simple calibration process, high calibration precision, fast calibration speed and the like.
Owner:XI AN JIAOTONG UNIV

Random trihedron-based radar-camera system external parameter calibration method

InactiveCN103049912ALow noise immunityLow operational complexity requirementsImage analysisEssential matrixRadar systems
The invention discloses a random trihedron-based radar-camera system external parameter calibration method. According to the method, an external parameter of a system can be solved with only two frames of data by using a trihedron scene a natural environment. The method comprises the following steps of: stipulating a world coordinate system by using a trihedron; performing planar fitting on the trihedron observed in a radar system to obtain a parameter of each plane and solving conversion relation of the world coordinate system and the radar coordinate system and relative motion between the two frames of data under the radar coordinate system; and in a camera system, solving an essential matrix by using matching characteristic points extracted by front and rear frames, then solving relation motion under the camera coordinate system, solving the plane parameter under the camera coordinate system by using the parameter under the radar coordinate system, finally solving an external parameter of a radar-camera, and performing final optimization by using coplanarity of points on corresponding planes under the two coordinate systems. A scene required by the method is simpler; and the method has the characteristics of high anti-interference performance, simple experimental equipment and high flexibility.
Owner:ZHEJIANG UNIV

A road boundary detection and tracking method based on a three-dimensional laser radar

The invention relates to a road boundary detection and tracking method based on a three-dimensional laser radar. The method comprises the following steps: converting polar coordinate data of a laser radar scanning point into rectangular coordinate data; Extracting ground points by using a random sampling consistency plane fitting method and a principal component analysis method; Roughly extractingroad boundary feature points by adopting a multi-feature, wide-threshold and hierarchical feature point extraction method; Dividing the roughly extracted road boundary feature points into a left roadboundary feature point and a right road boundary feature point by using a projection-based method by referring to the idea of linear discriminant analysis; Respectively filtering the left road boundary point and the right road boundary point by using a random sampling consistency method to obtain final road boundary points; Fitting the left road boundary line and the right road boundary line by adopting a quadratic polynomial random sampling consistency method; And tracking the road boundary line by adopting a Kalman filtering method based on amplitude filtering. The method can be used for processing various complex scenes and working conditions, and can be widely applied to unmanned driving.
Owner:JILIN UNIV

Road vision detection method combined with laser point cloud data

The invention discloses a road vision detection method combined with laser point cloud data, belongs to the field of unmanned driving, and solves the problem of multi-sensor fusion in the prior art. The method comprises the steps of performing data-level fusion on the point cloud data and the image data; performing road division on each frame of image in the image data, and performing conversion after division to obtain an illumination-invariant space image; according to the M estimation sample consistency, performing plane fitting on the point cloud data after data level fusion to obtain a point cloud data coarse division result; performing road feature extraction on each frame of image, the illumination-invariant space image and the point cloud data coarse division result of the image data after data level fusion and the point cloud data after data level fusion corresponding to each frame of image; respectively sending the extracted road features into two random forests for training,and obtaining probability output of each pixel point and probability output of each point cloud data; and constructing each point cloud-image mixed conditional random field to obtain a road area. Themethod is used for road vision detection.
Owner:UNIV OF ELECTRONICS SCI & TECH OF CHINA

Parcel volume measuring method and system, storage medium and mobile terminal

The invention discloses a parcel volume measuring method and system, a storage medium and a mobile terminal, and relates to the field of computer vision. Target point cloud is obtained, and the targetpoint cloud at least comprises the point cloud of a support surface and the point cloud of the top surface of a to-be-measured parcel; a plane equation of the support surface and the plane equation of the top surface of the to-be-measured parcel and the point cloud of the top surface of the to-be-measured parcel are obtained in a plane fitting mode, and the height of the to-be-measured parcel iscalculated according to the plane equation of the support surface and the plane equation of the top surface of the to-be-measured parcel; and the point cloud of the top surface of the to-be-measured parcel is projected on a plane corresponding to the plane equation of the to-be-measured parcel top surface to obtain a boundary point cloud; four frame angle points of the top surface frame of the to-be-measured parcel are obtained; according to the coordinates of the four frame angle points, the length and the width of the to-be-measured parcel are obtained through calculation, and the height ofthe to-be-measured parcel is combined, the volume of the to-be-measured parcel is obtained through calculation. The purpose of reducing the measurement error and simplifying the measurement requirement is achieved.
Owner:NANJING AVATARMIND ROBOT TECH CO LTD

Method for detecting hook face circular hole based on three-dimensional point cloud

ActiveCN103886593AAccurate round hole axial vectorExact radius valueImage analysisCharacter and pattern recognitionCircular coneLeast squares
The invention provides a method for detecting a hook face circular hole based on a three-dimensional point cloud. The method comprises the steps that firstly, three-dimensional points on the edge of the circular hole to be detected on the point cloud are accurately extracted; then least square plane fitting is conducted on the edge points of the circular hole, so that an initial plane of a projection is obtained, the edge points are projected to the plane, and a coordinate system is converted, so that two-dimensional points of the projection are obtained; the radius of a least square circle and two orthogonal fixing rotary axes of the projection points are obtained; when the radius of the circle can not meet the judgment criterion of the circle, a least square plane respectively rotates around the two rotary axes, projection and iterative computation are conducted again until the radius of the circle meets the judgment criterion of the circle, so that the normal of the least square plane is the axial direction of the circular hole and the radius of the least square circle of the projection two-dimensional points is the radius of the circular hole. According to the method, the axial direction and the radius of the circular hole can be rapidly detected from the three-dimensional point cloud.
Owner:HUAQIAO UNIVERSITY

Building point cloud registration algorithm based on dimension reduction

The invention discloses a building point cloud registration algorithm based on dimension reduction, comprising the following steps: respectively acquiring building point cloud data at two sampling points at different angles of view, and numbering all the points in the point clouds; selecting the overlapping areas of the building point clouds at the two angles of view, and carrying out building point cloud plane fitting on the overlapping areas by means of the least square method to obtain a projection surface of the building point clouds; projecting the building point clouds on the building projection surface, and determining the coordinates of the projection points of all the points in the point clouds after the points in the point clouds are vertically projected on the building projection surface; re-sampling the projection points, and determining a two-dimensional image of the building point clouds after dimension reduction; searching same-name points in the two-dimensional image through template matching based on difference of squares; indexing the searched same-name points of the two-dimensional image back to a three-dimensional point cloud according to the mark number; and getting rotation and translation variables by means of the unit quaternion method according to the points in the three-dimensional point cloud indexed based on the same-name points, and applying the rotation and translation variables to the overall building point cloud. By using the method, the efficiency of registration is improved.
Owner:JIMEI UNIV

Laser radar and camera combined calibration method based on mobile calibration plate

The invention discloses a laser radar and camera combined calibration method based on a mobile calibration plate. Firstly, calibration internal parameters are calculated for different poses of a calibration plate; a normal vector of a point cloud data fitting plane of the selected corresponding laser radar calibration plate is acquired, and calibration external parameters are calculated through equation solving to finally complete calibration. The method comprises the following specific steps: step 1, collecting laser radar and camera data of calibration plates at different angles in the viewfield of a camera as calibration data and verification data; 2, acquiring a camera internal reference calibration result of the acquired camera data by using a Zhang Zhengyou calibration method; 3, selecting a calibration plate position point cloud on the corresponding laser radar data; step 4, carrying out plane fitting on the point cloud data obtained in the step 3 and obtaining a correspondingnormal vector; and step 5, substituting the internal reference data obtained in the step 2 into a corresponding calculation formula to obtain a final external reference result. Compared with a single-point selection method, the method for selecting the plane data of the calibration plate is higher in accuracy and simpler to operate.
Owner:JIANGSU UNIV

Method for measuring three-dimensional roughness of rock mass structural surface based on triangle area ratio method

The invention provides a method for measuring three-dimensional roughness of a rock mass structural surface based on a triangle area ratio method, and belongs to the field of the geotechnique in civil engineering. A digital photogrammetry system is utilized to acquire the structural surface, the three-dimensional space form of the whole structural surface is reflected according to the surface form of the exposed part of the structural surface, plane fitting is conducted on the structural surface through the least square method, the ratio of the total area of triangular meshes of the structural surface to the plane area is calculated and reflects the smooth degree of the fit structural surface. The advantage of a photogrammetry method that three-dimensional data of the structural surface can be quickly and accurately measured is fully utilized, the surface of the structural surface is reconstructed through a Delaunay triangulation method on the basis, and then the surface form of the structural surface is reflected through the three-dimensional triangular meshes. On the basis of reconstructing the surface of the structural surface in a three-dimensional mode, a specific area method is provided, and the magnitude of roughness is reflected according to the ratio of the area of the meshes of the structural surface to the fitting area.
Owner:NORTHEASTERN UNIV

Point-cloud feature point extraction method based on local sub-neighborhood division

The invention provides a point-cloud feature point extraction method based on local sub-neighborhood division. The method includes the four steps of the initial feature point extraction stage, the local triangle construction stage, the local sub-neighborhood division stage and the robust feature point extraction stage. At the initial feature point extraction stage, potential initial feature points of input point cloud data are acquired. At the local triangle construction stage, in order to effectively extract true feature points from an initial feature point set, a triangle set capable of reflecting the local geometrical feature structure of the corresponding point is established in a local neighborhood of each initial feature point. At the local sub-neighborhood division stage, the normal of each constructed local triangle set is clustered, local neighborhood points at one point can be clustered, and thus sub-neighborhood division of the local neighborhood points at one point can be achieved. At the robust feature point extraction stage, local plane fitting is conducted on the data points in the divided sub-neighborhood, and accordingly the true feature points can be recognized by judging whether current points fall on intersection lines of a plurality of planes at the same time or not.
Owner:BEIHANG UNIV +1

Evaluation method of tooth profile deviation of involute cylindrical spur gear under influence of installation error

The invention discloses an evaluation method of the tooth profile deviation of an involute cylindrical spur gear under the influence of installation error. Firstly, establishing a machine coordinate system O0-X0Y0Z0 to measure the tested gear under the machine coordinate system. The measuring positions include the upper and lower section points of the measured gear mandrel, upper end of the gear and the measuring point of the tooth profile, so that the tooth profile measuring point under the influence of the installation error is obtained. According to the two cross-section points of the mandrel under the machine coordinate system, conducting the least-square circular fitting to work out rotating shaft equation to establish the coordinate system O1-X1Y1Z. The tooth-profile measuring pointis restored to the initial position and the error of the rotation axis of the tooth-profile measuring point is corrected. The least-square plane fitting is performed on the measuring point on the upper end face of the measured gear, and the coordinate system O2-X2Y2Z2 is established with the normal vector direction of the upper end face of the measured gear being the Z2 axis with the aim of correcting the inclination error of the tooth-profile measuring point. Finally the influence of the installation error on tooth profile deviation evaluation is corrected based on the tooth profile deviationvalue worked out by calculating the rotation angle to the measuring point of the design tooth profile around gear base circle center.
Owner:BEIJING UNIV OF TECH

Binocular visual multi-line projection structured light calibration method

The invention discloses a binocular visual multi-line projection structured light calibration method. The method comprises the following steps that 1) the sequence numbers of light stripes are determined; 2) left and right cameras collect a lattice image, four corners of a lattice are clicked, initial estimated positions of other intersection points in the lattice are obtained, and sub-pixel coordinates of intersection points are obtained by using an Ostu threshold method and a gray scale weighted average method in a k*k neighborhood of the initial estimated positions of intersection points; 3) 3D coordinates of the intersection points are obtained; and 4) the steps 1-3 are repeated, the 3D coordinates of the intersection points obtained in multiple times are classified according to the sequence numbers of the light stripes, for all points belonging to the same structured light plane, a least square method is used to carry out planar fitting on the 3D coordinates of the intersection points belongs to the same structured light to obtain a plane equation, and calibration is not completed until all the structured light planes are in the planar equation of the system coordinate system. The method has the advantages that a calibration board has no requirements for planarization, manufacture is simple, calibration is flexible, no auxiliary equipment is needed, the method is suitable for onsite calibration and the versatility is high.
Owner:SOUTH CHINA UNIV OF TECH
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