Goaf laser scanning point cloud triangulation methodology based on the surfaces of revolution
Technical field
The present invention relates to a kind of goaf laser scanning point cloud triangulation methodology based on the surfaces of revolution.
Background technology
The goaf that underground metal mine exploitation is formed【Goaf refers to the dead zone that mining is formed】Often cause ore deposit
Mountain mining conditions deteriorate, and adjacent operation area stope and roadway maintenance are difficult, or even cause down-hole large area inbreak, rock shifting, earth's surface
The disaster such as subside, Mine Safety in Production is constituted a serious threat.At present, the Detection Techniques in domestic and international goaf mainly have engineering drill
The technology such as spy, geophysical exploration, laser scanning, detecting, in terms of the three-dimensional configuration of accurate acquisition goaf, laser scanning, detecting
Technology has certain advantage, its cloud data detecting【Point cloud refers to that the space obtaining each sampled point of body surface is sat
The set of the point obtaining after mark, referred to as " point cloud ".Point cloud (Point Cloud) is expression target under the same space referential
The magnanimity point set of spatial distribution and target surface characteristic.The point cloud being obtained according to laser measurement principle, including three-dimensional coordinate
(XYZ).】Goaf triangulation network physical model can be set up【Triangulation network physical model refers to be used by the patch grids that triangle forms
Physical model in the three-dimensional configuration of simulation entity】, triangulation network physical model can be used for mining design, stope mining index meter
The aspects such as calculation, numerical simulation analysis, visualization security control.Wide dead zone laser scanning, detecting equipment is applied to have Canada
Cavity Monitoring System CMS and Britain dead zone automatically scanning laser system C-ALS.
By laser scanning, detecting equipment, goaf is detected, its operation principle is as follows:By connecting rod by laser
Probe stretches into dead zone, and during detection, 360 ° of probe rotates and passes through laser and continuously measures gob edge point information, often scans
After a complete circle, probe is automatically raised predetermined angle and is carried out the scanning of a new circle, until completing whole detection operations, CMS
Detection principle is as shown in Figure 1.
Preferably laser acquisition data in dead zone is the orderly point cloud of very rule, and angle is certain between points, one
Circle connects a circle arrangement.And because goaf steam is big, dust is many, have the unfavorable factors such as ponding, partial barriers during actual detection
Impact, leads to a cloud information may produce noise spot or situations such as local data loses, destroys the due of scanning element cloud and open up
Flutter rule, this produces very detrimental effect for orderly point cloud triangulation【Point cloud triangulation refers to according to certain rule
Then with a cloud as summit, build a series of triangles, all triangles are not overlapping, do not intersect, seamless unoccupied place forms a triangle
Net curved surface.】.
The existing algorithm orderly of goaf cloud being carried out to triangulation, have triangulation methodology based on grid,
Maximum subtended angle triangulation methodology.The thinking of the triangulation methodology based on grid is first by the point between circle and circle in order
First it is linked to be square grid, then each grid is divided into two triangular mesh, its method schematic diagram is as shown in Figure 2.Maximum
Subtended angle triangulation methodology is with reference to the line (new two summits of triangle) between circle and circle, selects according to maximum subtended angle principle
The larger adjoint point of subtended angle in two circles, as the 3rd summit of new triangle, constantly updates and is finally completed whole triangulations, its side
Method schematic diagram is as shown in Figure 3.
Consider the triangulation methodology based on grid of the orderly topological relation of a cloud and maximum subtended angle triangulation methodology,
Laser acquisition cloud data is more complete, spatial topotaxy intact in the case of, preferable triangle gridding can be built
Model.But in practical situations both, lack when cloud data, when spatial topotaxy is destroyed, the Triangulation Network Model of structure
Arise that local long-narrow triangular mesh or model local deformation.
Discounting for the regularity of a cloud, studied as dispersion point cloud, the main method referring at present has
Three-dimensional Delaunay Triangulation method, front (forward position) propelling method (Advancing Front Method) and Octree
(Octree) method etc..Said method for complicated form goaf laser scanning point cloud carry out triangulation aspect research should
With little, due to not accounting for the existing topological law of laser scanning point cloud, algorithm complex is high, and efficiency is low, and effect is not yet tested
Card;Not strong to the applicability in the goaf of complicated form, not yet have a kind of very effective at random for gob edge at present
Point cloud Precise modeling.
Content of the invention
Technical problem solved by the invention is, for the deficiencies in the prior art, provides a kind of mined out based on the surfaces of revolution
Area's laser scanning point cloud triangulation methodology, makes full use of the space topological rule of goaf laser scanning point cloud, compares scattered points
Cloud triangulation efficiency high;Adverse environmental factors impact is led to obtain imperfect and topological relation destruction scanning element cloud simultaneously
Data is using the method for topological law reparation and triangulation, higher than existing orderly cloud triangulation methodology accuracy.
The technical scheme is that:
A kind of goaf laser scanning point cloud triangulation methodology based on the surfaces of revolution,
Using laser scanning, detecting equipment, goaf is detected, by connecting rod, laser scanning head is stretched into mined out
Area, 360 ° of probe rotates and passes through laser continuous probe gob edge point information, the point that probe scanning one circle obtains according to
Secondary connected, form a surface sweeping circle;After scanning through a circle, probe is automatically raised predetermined angle and is carried out the scanning of a new circle, directly
To completing whole detection operations;Finally give Y scanning circle;
Then carry out laser scanning point cloud triangulation according to the following steps:
Step one:Set projection sphere, be calculated point cloud projection data:Probe position is set as the ball of sphere
The heart, the radius of sphere is set as 0.5~2 times of stope design length;By spherical projection method the spot projection on scanning circle
To on sphere, formed and enclose corresponding Y projection circle with Y scanning, be designated as Q successively1Circle, Q2Circle ..., QyCircle ..., QYCircle;Wherein
Y is projection circle sequence number;
Step 2:Carry out interpolation processing:
Judge that, with the presence or absence of point disappearance on each projection circle, method is successively:If the point on certain projection circle for one is
Arrange equidistant point, then there is not point data disappearance, do not carry out interpolation processing;If between adjacent 2 points of the upper local of projection circle
Distance more than this punctuate between 1.5 times of average distance then it is assumed that apart from excessive, then there is point disappearance in explanation, need into row interpolation
Process;All of projection circle and this corresponding scanning of projection circle are enclosed into row interpolation;
Step 3:Optimum grid is extracted based on the surfaces of revolution:
To project the central point line that on sphere, all projections are enclosed as rotary shaft, successively from QyExtract in order a little in circle
QY, iForm plane with rotary shaft【The so-called surfaces of revolution refers to, because circle midpoint is ordered as clockwise or counterclockwise, so from circle
Extracting point in order with rotary shaft composition plane plane is constantly to promote rotation forward, therefore is defined as the surfaces of revolution.The surfaces of revolution
Illustrate as shown in Figure 7.】, search adjacent circle Qy+1Apart from the point that this plane is nearest on circle;From QyPoint Q is extracted in circleY, i+1With rotary shaft
Composition plane, search adjacent circle Qy+1Apart from the point that this plane is nearest on circle, then point QY, i, point QY, i+1Enclose Q with adjacenty+1Search on circle
The closure circle forming away from two nearest points of adjacent plane respectively arriving, is approximately a grid, is defined as optimum grid;
Wherein subscript y of Q is the sequence number of projection circle, y=[1, Y];I is the sequence number of the point on projection circle, i=[1, I], I
For the points on projection circle;
Make y initial value be 1, i initial value be 1, successively search extract on sphere all of optimum grid;
Step 4:Carry out the triangulation of sphere upslide cinema-circle based on optimum grid:
It is located at adjacent circle Qy+1Search on circle respectively away from two nearest points of two adjacent planes be point QY+1, nAnd point
QY+1, m;
If QY+1, nAnd QY+1, mFor Qy+1Adjacent two points on circle, then (QY+1, n, QY+1, m, QY, i) constitute a triangle,
(QY+1, m, QY, i, QY, i+1) constitute a triangle;
If QY+1, nAnd QY+1, mFor Qy+1Same point on circle, then (QY, i, QY, i+1, QY+1, n) constitute a triangle;
If QY+1, nAnd QY+1, mFor Qy+1Enclose two points of two non-conterminous points, then adopt centre position determining method to optimum
Grid carries out triangulation, specifically:
Take the integer part of the value that p is (n+m)/2, point QY+1, pIt is point QY+1, nWith point QY+1, mIntermediate position points;For
Point QY+1, x, as n≤x<During p, (QY+1, x, QY+1, x+1, QY, i) group triangularity;As x=p, (QY, i, QY, i+1, QY+1, x) composition three
Angular;Work as p<During x≤m, (QY+1, x, QY+1, x-1, QY, i+1) group triangularity;Wherein subscript n, m, p, x are Qy+1Point on circle
QY+1, n, QY+1, m, QY+1, x, QY+1, pSequence number;
In this manner, generate the triangle grid model of spherical projection point cloud;
Step 5:According to the projection corresponding relation of point cloud projection and actual measurement scanning element cloud, corresponding generation surveys scanning element cloud
Triangle grid model.
Further, in described step 2, to all of projection circle and this projection circle corresponding scanning circle by with lower section
Method enters row interpolation:
(1) calculate projection circle the distance between upper adjacent 2 points, if distance more than this punctuate between 1.5 times of average distance
Then think presence point disappearance, need the new point P of insertionN;
(2) calculate the distance between upper adjacent 2 points of projection circle, if on certain projection circle, adjacent 2 points of P2And P3Between away from
From more than 1.5 times of this average distance of punctuating, then in line segment P2P3On away from point P2Distance be d1Place insertion point PN, wherein d1For
This average distance of punctuating, according to linear scale on this projection circle corresponding scanning circle, with line segment P2P3Corresponding line segment A2A3
Upper insertion newly point AN, insertion point ANPosition meet linear ratio relation d1:d2=d3:d4, wherein d2For line segment PNP3Length,
d3For line segment A2ANLength, d4For line segment ANA3Length;
Further, probe scanning one circle obtains 320 340 points;After scanning through a circle probe automatically raise pre-
If 5 degree of angle;Until probe is lifted to 140 degree and completes whole detection operations【I.e. the inclination angle scope of probe is 0 °
140°】.
Beneficial effect:
The present invention is based on rotation face goaf laser scanning and puts cloud triangulation methodology in order, and the method first passes through and is based on
After the orderly point interpolation method of spherical projection enters row interpolation, restore the space topological rule of scanning element cloud rule, then with sphere
Upper scanning circle central point line be rotary shaft, successively from one circle extract point generate a surfaces of revolution, on the basis of Plane of rotation
Next circle search can generate the point of optimum grid, completes triangulation on the basis of optimum grid.The present invention is from Practical Project
Application is set out, it is considered to due to not on the basis of fully understanding and applying goaf Point Cloud of Laser Scanner spatial topotaxy
Scanning cloud data that sharp such environmental effects lead to is imperfect and topological relation destroys situation it is proposed that a set of effective solution
Method.
The cloud data that one aspect of the present invention is directed to the Laser Detection Technique acquisition of similar dead zone is carried out based on spherical projection
Point interpolation in order, to repair orderly point cloud spatial topotaxy so as to reduce due topological law, the method is more practical,
Implement relatively easy;Make full use of the spatial topotaxy of goaf laser scanning point cloud it is ensured that the effect of triangulation
Rate.Repair topological relation, combine rotary shaft and the optimum grid of rotation faceted search generation, in this base by spherical projection interpolation simultaneously
Complete triangulation on plinth it is ensured that build Triangulation Network Model accuracy.
For orderly point cloud it is proposed that a kind of brand-new based on surfaces of revolution searching method, to obtain optimum grid;Have studied
Based on the grid triangulation methodology of the surfaces of revolution, can realize to goaf laser acquisition point cloud triangulation very well, by base
In the orderly point interpolation of spherical projection, compensate for counting due to the local that environmental impact factor (dust, steam, ponding etc.) leads to
According to disappearance, relatively it is based on grid triangulation methodology and maximum subtended angle triangulation methodology has more preferable performance.
Brief description
Fig. 1 goaf laser scanning, detecting schematic diagram;
Fig. 2 is the triangulation schematic diagram in prior art based on grid;
Fig. 3 is maximum subtended angle triangulation schematic diagram in prior art;
Fig. 4 is the inventive method flow chart;
Fig. 5 is spherical projection schematic diagram of the present invention;
Fig. 6 scans circle and projection circle grade ratio Interpolation Principle figure for the present invention;
Fig. 7 is surfaces of revolution schematic diagram of the present invention;
Fig. 8 is present invention optimum grid schematic diagram;
Fig. 9 is the special circumstances of present invention optimum grid;
Figure 10 is present invention optimum grid triangulation methodology;
The grid triangulation effect analysis based on the surfaces of revolution for the Figure 11, wherein 11 (a) is based on grid triangulation
11 (b), is the triangulation 11 (c) based on maximum subtended angle, is the triangulation based on the inventive method.
Specific embodiment
Below in conjunction with the drawings and specific embodiments, the present invention is described in more detail.
The present invention realizes that step is as follows, and method flow diagram is shown in Fig. 4:
Using laser scanning, detecting equipment, goaf is detected, laser scanning head is stretched into by dead zone by connecting rod,
During detection, 360 ° of probe rotates and passes through laser and continuously measures gob edge point information, and after often scanning through a circle, probe will
Automatically raise predetermined angle and carry out the scanning of a new circle, until completing whole detection operations.
1. pass through spherical projection, unconspicuous for rule original position point cloud is converted to a-circle-by-a-circle umbilical point cloud, to sphere
Point cloud enters row interpolation, repairs original spatial topotaxy, and synchronization enters row interpolation to original position point cloud.
2. generate the surfaces of revolution by the point on enclosing on sphere and centre rotational axis, search element neighbour's circle remote from the nearest point of the surfaces of revolution,
Build optimum grid.
3. triangulation is carried out to optimum grid using centre position determining method, and synchronization is put cloud in situ to goaf and carried out
Triangulation, obtains the triangle grid model in goaf.
Hereinafter key step is described in more detail:
Orderly point interpolation method based on spherical projection
Determine projection sphere:Scanning center is set as projecting the centre of sphere of sphere, the radius of projection sphere is set to stope and sets
0.5~2 times of meter length.Gob edge data laser scanning, detecting device scan one circle being detected by spherical projection
Project on sphere, form a projection circle;
Carry out interpolation processing.As shown in Figure 5
Judge whether that point data lacks:If the data on projection circle is a series of point at equal intervals, do not deposit
In point data disappearance, do not carry out interpolation processing;If distance is excessive between the consecutive points of the upper local of projection circle, illustrate exist a little
Shortage of data, is processed in the enterprising row interpolation of projection circle;Synchronize interpolation according to linear etc. punctuating than relation pair actual scanning.Tool
Body:The method of interpolation is illustrated as shown in fig. 6, interpolation method is described as follows:
(1) calculate projection circle the distance between upper adjacent 2 points, if distance more than this punctuate between 1.5 times of average distance
Then think presence point disappearance, need the new point P of insertionN.
(2) in line segment P2P3On away from point P2Distance be d1Place insertion point PN, wherein d1For this average distance of punctuating, PNP3
Length be d2, obtain d1With d2Linear scale, according to linear scale scanning circle on line segment A2A3Upper insertion newly point AN, insertion
Point meets linear ratio relation d1:d2=d3:d4;
(3) successively all of scanning is enclosed into row interpolation, restore scanning and enclose due space topological rule.
It is to be laid a good foundation based on the grid triangulation of the surfaces of revolution based on the orderly point interpolation of spherical projection.
Optimum grid is extracted based on the surfaces of revolution
The so-called surfaces of revolution with the central point line of projection sphere upslide cinema-circle as rotary shaft, encloses (Q from certain successivelyyCircle) in
Extract point in order and form plane with rotary shaft;【Because circle midpoint is ordered as clockwise or counterclockwise, so plane is continuous
Promote rotation forward, therefore be defined as the surfaces of revolution.The surfaces of revolution is illustrated as shown in fig. 7, clearer in order to show, Fig. 7 only draws
5 projection circles and the corresponding surfaces of revolution of 6 points, in practical application, include more projections and enclose and the surfaces of revolution.】
By QyPoint on circle and rotary shaft build rotation faceted search adjacent circle Qy+1Apart from the point that the surfaces of revolution is nearest on circle:By
Point QY, iForm Plane of rotation and point Q with rotary shaftY, i+1Form Plane of rotation with rotary shaft, search for adjacent circle Q respectivelyy+1Distance on circle
The nearest point of the surfaces of revolution, if the point searching is respectively QY+1, nAnd QY+1, m, point QY, i、QY, i+1、QY+1, nAnd QY+1, mThe closure of composition
Circle, is approximately a grid, is defined as optimum grid, as shown in Figure 8.
Triangulation is carried out based on optimum grid
Generally, optimum grid is in QyCircle and Qy+1Circle respectively takes two consecutive points, and that is, 2:2 optimum grid.
Special circumstances one:In Qy2 points are taken, two surfacess of revolution are in Q in circley+1The closest approach of circle is same point, that is, 2:1
Optimum grid;
Special circumstances two:In Qy2 points are taken, two surfacess of revolution are respectively in Q in circley+1The closest approach of circle is non-conterminous point,
I.e. optimum grid is 2:N situation.Optimum grid special circumstances are as shown in Figure 9.
If two adjacent planes are in adjacent circle Qy+1The two nearest points searching on circle are respectively Qy+1Point Q on circleY+1, n
With point QY+1, m;
If QY+1, nAnd QY+1, mFor Qy+1Adjacent two points on circle, then (QY+1, n, QY+1, m, QY, i) constitute a triangle,
(QY+1, m, QY, i, QY, i+1) constitute a triangle;
If QY+1, nAnd QY+1, mFor Qy+1Same point on circle, then (QY, i, QY, i+1, QY+1, n) constitute a triangle;
If QY+1, nAnd QY+1, mFor Qy+1Enclose two points of two non-conterminous points, then adopt centre position determining method to optimum
Grid carries out triangulation, and method is illustrated as shown in Figure 10;Specifically:
Take the integer part of the value that p is (n+m)/2, point QY+1, pIt is point QY+1, nWith point QY+1, mIntermediate position points;For
Point QY+1, x, as n≤x<During p, (QY+1, x, QY+1, x+1, QY, i) group triangularity;As x=p, (QY, i, QY, i+1, QY+1, x) composition three
Angular;When judging position p<During x≤m, (QY+1, x, QY+1, x-1, QY, i+1) group triangularity;Wherein subscript n, m, p, x are Qy+1On circle
Point QY+1, n, QY+1, m, QY+1, x, QY+1, pSequence number;
In this manner, generate the triangle grid model of spherical projection point cloud;By based on optimum grid triangulation, can
Generate the triangle grid model of spherical projection point cloud, because point cloud projection and eyeball cloud are sequentially consistent in storage container
, by triangular apex, in storage container, position is applied to eyeball cloud container, can synchronously generate eyeball cloud triangle gridding
Model.
The grid triangulation effect analysis based on the surfaces of revolution for the Figure 11, wherein 11 (a) is based on grid triangulation,
11 (b) is the triangulation based on maximum subtended angle, and 11 (c) is the triangulation based on the inventive method.Simulation result shows, 11
A () is also easy to produce long and narrow deforming triangle based on grid triangulation methodology under point data deletion condition, and 11 (b) is based on maximum
Subtended angle triangulation is then easy to the situation of triangular apex excessively concentration, and the inventive method compensate for depositing in first two algorithm
Local defect, can realize to goaf laser acquisition point cloud triangulation very well, by orderly based on spherical projection
Point interpolation, compensate for the partial points shortage of data leading to due to environmental impact factor (dust, steam, ponding etc.), compared with 11 (a) base
Being based on maximum subtended angle triangulation methodology in grid triangulation methodology and 11 (b) has more preferable performance.