CN104021259A - Ground scanning major-point cloud orientation method - Google Patents

Abstract

The invention provides a ground scanning major-point cloud orientation method which comprises the steps: 1, identifying manually distributed orientation targets in mass point cloud data, calculating coordinates of center of spherical orientation targets in a scanning coordinate system; 2, removing spherical orientation target, namely pseudo orientation targets, which are identified in the step 1 and have a radius equivalent to that of the manual orientation target; and 3, performing automatic calculation and coordinate transformation on point cloud orientation parameters, namely, covering coordinates of the centers of the remained orientation targets into coordinates of ground control points corresponding to the centers of the remained orientation targets to obtain coordinates of the centers of the orientation targets in an engineering surveying coordinate system, and then solving a point cloud orientation parameter according to scanning coordinates of the orientation targets, and finally, performing the coordinate transformation through the point cloud orientation parameter to realize major-point cloud orientation. According to the ground scanning major-point cloud orientation method, through automatic detection of the orientation targets and the rejection of the pseudo orientation target, a long-distance spherical orientation target surface point distribution rule can be found, and thus automatic major-point cloud orientation of more than 0.1 billion points is realized.

Description

The a little bigger cloud orientation method of ground based scanning

Technical field

The invention provides a little bigger cloud orientation method of a kind of ground based scanning, belong to engineering survey field.

Background technology

Three Dimensional Ground laser coordinate system when scanning is the self-defined coordinate system of instrument, in the time of will be for engineering survey, the all survey site cloud of works scope need be transformed in engineering specified measurement coordinate system, while namely determining scanning, instrument is in location point and the attitude of engineering survey coordinate system, and this process is called a cloud orientation.Because laser scanning cannot be carried out autotelic scanning and accurately obtain its three-dimensional coordinate some points, while using spherical target, can obtain the coordinate of Target Center point, be unique method of carrying out high-acruracy survey by scanning.But in the situation that target size is certain, along with the increase of target to scanning movement spacing, drop on the lip-deep point of target fewer and feweri, density and reflectivity decrease, and arrive certain distance 200m in addition by the target of None-identified diameter 18cm.

Three Dimensional Ground laser scanning speed is more and more faster, and some cloud quantity is increasing, as sweep velocity be 101.6 ten thousand point/second instrument, if the acceptance rate by 30% calculates, per secondly receive 300,000 points, 6 minutes number of scan points surpass 100,000,000, account for disk space 2.85GB.For the Duo double-core CPU of internal memory 2GB, T6600, the normal domestic use computing machine of dominant frequency 2.2GHz, by its internal memory and process points cloud ability, a cloud can be divided into point cloud, point cloud, a little bigger cloud and super large point cloud.Wherein point cloud point number is less than 2,000 ten thousand; Point cloud is counted 2,000 ten thousand-5,000 ten thousand, and scanning software can barely be processed; A little bigger cloud point number is more than 5,000 ten thousand, and common computer almost can not be processed.

Goal of the invention

The object of this invention is to provide a kind of a little bigger cloud orientation method of ground based scanning that directed target is automatically identified and surveyed and each site cloud is changed automatically to engineering survey coordinate system that can address the above problem, realize.Its technical scheme is:

The a little bigger cloud orientation method of ground based scanning, is characterized in that adopting following steps:

1) directed target automatic detection: the artificial directed target of laying of identification in mass cloud data, calculates spherical leading beacon pinwheel at the coordinate of scan coordinate system;

2) reject step 1) in identification radius and artificial orientation's target quite, be shaped as spherical directed target, suppose to target;

3) some cloud orientation parameter calculates and coordinate conversion automatically: by step 2) remaining leading beacon pinwheel is in the coordinate of the scan coordinate system ground control point coordinate conversion corresponding with this leading beacon pinwheel, obtain the engineering survey coordinate system coordinate of leading beacon pinwheel, then the scanning coordinate in conjunction with directed target carries out solving of a cloud orientation parameter, finally by a cloud orientation parameter, carry out coordinate conversion, realize the orientation of a little bigger cloud.

The a little bigger cloud orientation method of described ground based scanning, step 1) in, first arrange orienteering target reference mark achievement, from scanner, derive cloud data; Then scanning cloud data being carried out to three grades cuts apart: the first order is extracted the some cloud ring at all directed targets place, station, it is the some cloud bar that extracts each directed target place that the second level is cut apart, the third level is cut apart a cloud ring is cut apart to several sector regions, determine that the directed target of candidate is to each sector region layering, with every layer of some cloud, carry out sphere matching, calculate sphere centre coordinate, the radius of a ball, error of fitting and sphericity, when the matching radius of a ball, error of fitting, sphericity reach an index, think that this layer has directed target.

The a little bigger cloud orientation method of described ground based scanning, step 2) in, set n for rejecting supposition to remaining directed target number after target, reject supposition and to the step of target be:

1. between any two directed target i and j in the distance of engineering survey coordinate system, can be expressed as

D _E＝{D _ij},i＝1,2,…,n,j＝1,2,…,n,i≠j (1)

2. calculate each leading beacon target scan apart from matching factor ρ _t, a scanning distance D _smatching value T be defined as

Directed target k scanning distance matching factor ρ _tkbe calculated as follows

${\mathrm{\ρ}}_{\mathrm{Tk}}=\frac{\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{T}_i}{n}---\left(3\right)$

3. work as ρ _tkduring < 0.5, directed target k, for supposition is to target, is rejected.

Compared with prior art, its advantage is in the present invention: by automatic detection and the rejecting of supposition to target of directed target, can find out the remote spherical leading beacon target surface point regularity of distribution, realize a little bigger cloud self-orientation of more than 100,000,000 point.

Accompanying drawing explanation

Fig. 1 is embodiment of the present invention step 1) in determined some Yun Huantu;

Fig. 2 is embodiment of the present invention step 1) in determined some cloud bar figure;

Fig. 3 is embodiment of the present invention step 1) mid point cloud bar is by fan-shaped equidistant subregion schematic diagram;

Fig. 4 is embodiment of the present invention step 1) middle automatic detection directed target place fan section figure out;

Fig. 5 is the leading beacon target spot bitmap that in the embodiment of the present invention, scanner is measured.In figure: R ₁that directed target is to the minimum distance of scanning movement, R ₂that directed target is to the maximum distance of scanning movement, R _ibe the point of a cloud ring to the distance of scanning movement, 1,2,3,4 is true orientation target, 5 for supposition to target.

Embodiment

Below in conjunction with accompanying drawing 1～5, the invention will be further described.Test data used from certain mine actual scanning multistation analyzing spot cloud, scanner is Riegl VZ-1000.Mining area 3.2km*2.8km, scans 47 stations altogether, and every scanning movement is established 4～5 directed target balls, and every scanning movement scans approximately 100,000,000 points, and data processing is used the software with IDL language development, and the data file storage format of some cloud is scale-of-two.6 station scan-datas were example in the past, and the feasibility of this method is described.Spherical directed target is placed on the tribrach through leveling, and centre of sphere three-dimensional coordinate is measured by traditional measurement method.Set up after equidistant fan-shaped index, each fan section point cloud is surveyed and sphere matching, the theoretical radius of matching radius and ball is more or less the same when 1cm, thinks that may there be directed target in this district.

Step 1) directed target automatic detection: first arrange orienteering target reference mark achievement, derive cloud data from scanner; Then scanning cloud data being carried out to three grades cuts apart:

The first order is extracted the some cloud ring at all directed targets place, station, sees accompanying drawing 1, according to scanning movement and directed target reference mark, in the horizontal range information of engineering survey coordinate system, extracts the some cloud ring at directed target place from a little bigger cloud.Cloud data adopts segmentation to read technology, and every section is read 2,000,000 points, and whether pointwise is differentiated is the point of a cloud ring.R ₁that directed target is to the minimum distance of scanning movement, R ₂that directed target is to the maximum distance of scanning movement.

It is the some cloud bar that extracts each directed target place that the second level is cut apart, and sees accompanying drawing 2, and some cloud bar width is the radius of the directed target of maximum spherical, according to each directed target to scanning movement distance, each directed target loca cloud bar of rapid extraction from a cloud ring.

The third level is cut apart a cloud ring is cut apart to several sector regions, sees accompanying drawing 3, and no matter directed target is how far, the fan-shaped interior radius of circle of white with put that cloud bar is wide to be equated, from scanning movement more away from, fan section number is more, substantially equal to guarantee each sector region size; Determine that the directed target of candidate is to each sector region layering, see accompanying drawing 4, floor height is 1.95 times of the directed target radius of maximum spherical, every layer is carried out sphere matching centre of sphere radius, when the difference of matching radius and ball known radius is within the specific limits when (2 times of single-point errors in point measurement), this layer is thought directed target.

Step 2) reject and suppose to target: see accompanying drawing 5, reject supposition and remain 4 directed targets after target, rejecting supposition to the step of target is:

1. between any two directed target i and j in the distance of engineering survey coordinate system, can be expressed as

D _E＝{D _ij},i＝1,2,…,n,j＝1,2,…,n,i≠j (1)

2. calculate each leading beacon target scan apart from matching factor ρ _t, a scanning distance D _smatching value T be defined as

3. directed target k scanning distance matching factor ρ _tkpress following formula calculate the scanning distance matching factor ρ of directed target 5 in Fig. 5 _t5=0, other scanning distance matching factor is 1, judges that directed target 5 is to suppose to target, rejects it.

Step 3) some cloud orientation parameter calculates and coordinate conversion automatically: by step 2) remaining 4 leading beacon pinwheels are in the coordinate of the scan coordinate system ground control point coordinate conversion corresponding with this leading beacon pinwheel, obtain the engineering survey coordinate system coordinate of leading beacon pinwheel, with error compensation method, resolve instrument position and the attitude orientation parameter of scanning movement, by a cloud orientation parameter, will scan site cloud coordinate conversion to engineering specified coordinate is, completes a little bigger cloud self-orientation in ground based scanning station.

Experimental data proves: in the present invention, directed target Top Structure Automatic Detecting Arithmetic and supposition, to target automatic discrimination and rejecting, can solve common computer and obtain the 100000000 a little bigger clouds orientations in the single sweep station with last measurement point.

Claims (3)

1. a little bigger cloud orientation method of ground based scanning, is characterized in that adopting following steps:

1) directed target automatic detection: the artificial directed target of laying of identification in mass cloud data, calculates spherical leading beacon pinwheel at the coordinate of scan coordinate system;

2) reject step 1) in identification radius and artificial orientation's target quite, be shaped as spherical directed target, suppose to target;

3) some cloud orientation parameter calculates and coordinate conversion automatically: by step 2) remaining leading beacon pinwheel is in the coordinate of the scan coordinate system ground control point coordinate conversion corresponding with this leading beacon pinwheel, obtain the engineering survey coordinate system coordinate of leading beacon pinwheel, then the scanning coordinate in conjunction with directed target carries out solving of a cloud orientation parameter, finally by a cloud orientation parameter, carry out coordinate conversion, realize the orientation of a little bigger cloud.

2. a little bigger cloud orientation method of ground based scanning according to claim 1, is characterized in that step 1) in, first arrange orienteering target reference mark achievement, from scanner, derive cloud data; Then scanning cloud data being carried out to three grades cuts apart: the first order is extracted the some cloud ring at all directed targets place, station, it is the some cloud bar that extracts each directed target place that the second level is cut apart, the third level is cut apart a cloud ring is cut apart to several sector regions, determine that the directed target of candidate is to each sector region layering, with every layer of some cloud, carry out sphere matching, calculate sphere centre coordinate, the radius of a ball, error of fitting and sphericity, when the matching radius of a ball, error of fitting, sphericity reach an index, think that this layer has directed target.

3. a little bigger cloud orientation method of ground based scanning according to claim 1, is characterized in that step 2) in, set n for rejecting supposition to remaining directed target number after target, reject supposition and to the step of target be:

1. between any two directed target i and j in the distance of engineering survey coordinate system, can be expressed as

D _E＝{D _ij},i＝1,2,…,n,j＝1,2,…,n,i≠j (1)

2. calculate each leading beacon target scan apart from matching factor ρ _t, a scanning distance D _smatching value T be defined as

Directed target k scanning distance matching factor ρ _tkbe calculated as follows

${\mathrm{\&rho;}}_{\mathrm{Tk}}=\frac{\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{T}_i}{n}---\left(3\right)$

3. work as ρ _tkduring < 0.5, directed target k, for supposition is to target, is rejected.