CN104596415A - Method and device for determining lower edge of stack based on laser scanning single lines - Google Patents

Abstract

The invention discloses a method for determining a lower edge of a stack based on laser scanning single lines. The method comprises the following steps: 1, acquiring a spatial coordinate Pi=[Xi, Yi, Zi] of a scanning point on each laser scanning single line of a target stack; 2, calculating di; 3, comparing the obtained di with a threshold value Ti, wherein Ti=(N-1)/N*h-; when the kth scanning point meets a formula that dk is greater than Tk, the kth scanning point is determined as a boundary point of the scanning single line; a set of the boundary points of all laser scanning single lines of the target stack corresponds to the lower edge of the target stack. The invention also provides a device for determining the lower edge of the stack based on the laser scanning single lines. By using the method and the device, the lower edge of the target stack can be accurately determined.

Description

A kind of method and apparatus determining heap body lower limb based on laser scanning single line

Technical field

The present invention relates to heap swept-volume technical field, be specifically related to a kind of method and apparatus determining to pile body lower limb based on laser scanning single line.

Background technology

Along with speeding up the construction of large-scale coal storage base, the modern management technique that needs to stockpile and store ensures, and be an important step of stockpiling and storing in modern management to making an inventory of coal volume mass, measuring the volume of coal storage base dump heap body and quality rapidly, accurately, is simply the important process that scientific management, assessment of economic benefit and memory space assessment are carried out in coal storage base, has important using value.

Along with the development of laser technology, for dish coal brings a kind of contactless metering system, laser coal checking method conventional at present mainly contains portable disc coal instrument and fixed dish coal instrument.Portable disc coal instrument, by setting relevant sweep parameter and mobile device completes measurement automatically, more accurately obtains coordinate information by GPS location simultaneously, sets up three-dimensional model.Fixed dish coal instrument, can be fixedly mounted on the equipment such as stacker-reclaimer and to carry out making an inventory fast, accurately to fixing coal yard.Although what fixed dish coal instrument decreased portable disc coal instrument manually gets operation ready, there is inevitable scan blind spot, all effectively cannot make an inventory to each dump in whole stockyard.Laser scanner, while scanning dump, inevitably scans the ground data on dump side.When processing these ground datas, some dish coal instrument only will intercept required cloud data in angular range by setting laser scanning angle scope, this mode is applicable to fixed measurement, require that dump Edge divider is easily distinguished, but dump is because of different, therefore sufficiently large in set angle scope, still can introduce ground data; Some dish coal instrument are not then removing ground data, determined the marginal information of dump by the mode of Digital Image Processing after forming three-dimensional laser point cloud, useless point is not removed from laser point cloud itself, ask for heap body volume by the method for image procossing, and ground cloud data inevitably brings error to heap body volume computing in volume computing.

Summary of the invention

In view of this, the present invention proposes a kind of method and apparatus determining to pile body lower limb based on laser scanning single line, by carrying out a series of process to laser scanning single line cloud data, determines the lower limb of target heap body.

The present invention is a kind of determines the method for piling body lower limb based on laser scanning single line, comprising:

Step one: the volume coordinate P of analyzing spot on the laser scanning single line of acquisition target heap body _i=[X _i, Y _i, Z _i], wherein P _ibe i-th analyzing spot, i=1,2,3 ..., n;

Step 2: calculate according to following formula

${\stackrel{\‾}{h}}_{-}={\stackrel{\‾}{Z}}_{N-}-Z_i$

${\stackrel{\‾}{h}}_{+}=Z_i-{\stackrel{\‾}{Z}}_{N+}$

${\stackrel{\‾}{d}}_i={\stackrel{\‾}{h}}_{-}-{\stackrel{\‾}{h}}_{+}$

Wherein, with be respectively at P _ithe mean value obtained after N number of analyzing spot carries out windowing process is respectively got in front and back;

Step 3: by what obtain with threshold value T _icompare, wherein wherein when a kth analyzing spot meets time, this kth analyzing spot is defined as the separation of this scanning single line; Wherein, the lower limb of the set of the separation of all laser scanning single lines of target heap body corresponding target heap body.

Preferably, wherein the span of N is 10 < N < 20.

Beneficial effect of the present invention: embodiment of the present invention single scan line point cloud carries out rim detection, complete local by single line and detect, result is more accurate; The windowing smoothing processing of the embodiment of the present invention, averages to windowing before and after the determination point of single line, thus eliminates the jitter error because hardware error brings, and ensures the accuracy of algorithm process; The threshold adaptive process of the embodiment of the present invention, for added frame size, carries out adaptive analyzing and processing to decision threshold, ensures the accurate reliability of threshold value all the time.Utilize the present invention can obtain reliably, pile the separatrix on body lower limb and ground accurately, remove ground garbage, obtain and pile body information accurately, avoid the terrain surface specifications impact in the past existed in heap body three-dimensional modeling, volume and Mass Calculation.

Accompanying drawing explanation

Fig. 1 is the view of piling body with laser scanner scans of the embodiment of the present invention.

The algorithm principle figure of Fig. 2 embodiment of the present invention.

The algorithm schematic diagram of windowing process is carried out in Fig. 3 embodiment of the present invention.

The one-line scanning point Z coordinate schematic diagram of body without windowing process is piled in Fig. 4 embodiment of the present invention.

The one-line scanning point Z coordinate schematic diagram of body after windowing process is piled in Fig. 5 embodiment of the present invention.

Fig. 6 is the apparatus structure block diagram determining to pile body lower limb based on laser scanning single line of the embodiment of the present invention.

Embodiment

Below in conjunction with accompanying drawing and specific embodiment, technical scheme of the present invention is described in detail.

The present invention is based on laser scanning single line and determine that the principle of piling body lower limb is: use laser scanner scans heap body to obtain piling the laser point cloud of body, due to heap surface profile variations, the vertical of different scanning point highly must present the state of successively decreasing from top to bottom, there is a separation in the position had a common boundary at heap body and ground, more than separation for heap body divides, be above ground portion below separation, if the separation of each sweep trace then can be determined, also just determine the lower limb of whole heap body.Ground data is all rejected the heap body point cloud that can obtain removably face and ring, for piling body three-dimensional modeling, volume and Mass Calculation etc., result accurately and reliably.

Below describe and the present invention is based on the algorithm principle that laser scanning single line determines to pile body lower limb.

First, laser scanner is utilized to obtain the laser scanning single line point cloud coordinate of heap body.With reference to figure 1, body is piled by laser scanner scans, such as hand-held two dimensional laser scanning instrument is advanced one week around dump, the laser point cloud data of dump can be obtained, these cloud datas are set of some sweep traces of dump top-to-bottom (comprising part ground), and the volume coordinate that can obtain any point P on a scanning single line is P _i=[X _i, Y _i, Z _i], wherein footmark i represents i-th analyzing spot, i=1,2,3 ..., n.

Utilize the volume coordinate of analyzing spot, mainly Z coordinate calculates d _i.With reference to figure 2, for three adjacent analyzing spot P in single scan line _i-1, P _i, P _i+1, Z coordinate is respectively Z _i-1, Z _i, Z _i+1, then have:

h _-＝Z _i-1-Z _i

h ₊＝Z _i-Z _i+1(1)

d _i＝h _--h ₊

According to each analyzing spot in formula (1) successively traverse scanning single line, the d that each point is corresponding can be obtained _ivalue.

Wherein, for ground point, each point height is identical, has h _-=Z _i-1-Z _i=0, h ₊=Z _i-Z _i+1=0, the d that therefore ground point is corresponding _i=h _--h ₊=0; For the point on heap body, consecutive point height successively decreases, h _-value and h ₊value relatively, therefore piles d corresponding to body point _iclose to 0, h in the ideal situation _-=h ₊, then the d of body point is piled _i=h _--h ₊=0.

Be appreciated that and calculate the d that on single line, each analyzing spot is corresponding _iafterwards, can d corresponding to base area millet cake _i=0 and d corresponding to heap body point _iclose to 0, determine the point of interface piling body and ground.But, owing to there is equipment and scanning errors, in practical application scene, directly do not adopt d _i, but by carrying out windowing process to the analyzing spot on single line, eliminating measured deviation, below describing in detail.

Due to the existence of equipment and scanning errors, the Z coordinate (Z of analyzing spot _i-1, Z _i, Z _i+1) may measured deviation be there is, carry out windowing process for this reason, with reference to figure 3, before and after i-th point, respectively get N number of some windowing, get the mean value of the Z coordinate figure of N number of point, can Z be obtained _n-and Z _n+, the Z used when replacing formula (1) to calculate respectively _i-1and Z _i+1, have:

${\stackrel{\&OverBar;}{h}}_{-}={\stackrel{\&OverBar;}{Z}}_{N-}-Z_i$

${\stackrel{\&OverBar;}{h}}_{+}=Z_i-{\stackrel{\&OverBar;}{Z}}_{N+}---\left(2\right)$

${\stackrel{\&OverBar;}{d}}_i={\stackrel{\&OverBar;}{h}}_{-}-{\stackrel{\&OverBar;}{h}}_{+}$

The process that the multiple spot windowing of through type (2) is averaged, can eliminate the height relief deviation put near the frontier point that caused by measuring error, the wherein desirable 10 < N < 20 of frame size.Single scan line Z coordinate schematic diagram before Fig. 4 and Fig. 5 respectively illustrates windowing process and after windowing process, windowing process can improve the accuracy of searching frontier point.

It is corresponding that employing formula (2) calculates each point wherein, in the ideal case, all ground points and heap body point are had point only on ground with heap body intersection, namely separation is corresponding be not 0, and separation is corresponding

Then, in order to determine in single line, which point is the separation on heap body and ground, setting threshold value T _i:

$T_i=(N-1)/N*{\stackrel{\&OverBar;}{h}}_{-}---\left(3\right)$

Wherein, the frame size N chosen when N is windowing process.For each point, by its correspondence with threshold value T _icompare, if wherein a kth point meets then can determine that this kth point is exactly the separation of this scanning single line.All carry out above-mentioned process to each scanning single line in heap body point cloud, can obtain the separation of whole heap body point cloud, the set of these separations is exactly the lower limb of heap body.

Wherein, about threshold value determined by frame size self-adaptation by known its of its set-up mode.Due to heap body point close to 0, frontier point close to and containing forms N, therefore threshold value in formula (3) self-adaptative adjustment can be carried out according to the height of all analyzing spots and selected frame size, ensure the accuracy at every bar sweep trace edge.

According to foregoing description, for a scanning single line, be highly greater than (in Fig. 3, sequence number is less than the point of k) of separation for heap body point, (in Fig. 3, sequence number is greater than the point of k) that be highly less than separation is ground point.During data processing, ground point is rejected, retain heap body point, target that is complete, that do not comprise ground data heap volumetric laser cloud data can be obtained.

Correspondingly, can provide a kind of device determining to pile body lower limb based on laser scanning single line, with reference to figure 6, it comprises: laser scanner, computing module, threshold process module and separation determination module.

Wherein, laser scanner is for obtaining the laser scanning single line point cloud coordinate P of target heap body _i=[X _i, Y _i, Z _i]; Computing module is used for calculating according to formula (2) threshold process module is used for according to formula (3) calculated threshold T _i; Separation determination module is for by analyzing spot on scanning single line with threshold value T _icompare, when a wherein kth point is corresponding this kth point is defined as the separation of this scanning single line.

The embodiment of the present invention processes for single scan line point cloud, and factor affected by environment is little, and accuracy is high, and the three-dimensional modeling and the volume computing that can be follow-up heap body establish good basis.

Above, be described in detail in conjunction with specific embodiments to technical scheme of the present invention, described specific embodiment understands thought of the present invention for helping.The derivation that those skilled in the art make on the basis of the specific embodiment of the invention and modification also belong within scope.

Claims (4)

1. determine a method of piling body lower limb based on laser scanning single line, it is characterized in that, comprising:

Step one: the volume coordinate P of analyzing spot on the laser scanning single line of acquisition target heap body _i=[X _i, Y _i, Z _i], wherein P _ibe i-th analyzing spot, i=1,2,3 ..., n;

Step 2: calculate according to following formula

${\stackrel{\&OverBar;}{h}}_{-}={\stackrel{\&OverBar;}{Z}}_{N-}-Z_i$

${\stackrel{\&OverBar;}{h}}_{+}=Z_i-{\stackrel{\&OverBar;}{Z}}_{N+}$

${\stackrel{\&OverBar;}{d}}_i={\stackrel{\&OverBar;}{h}}_{-}-{\stackrel{\&OverBar;}{h}}_{+}$

Wherein, with be respectively at P _ithe mean value of the Z coordinate obtained after N number of analyzing spot carries out windowing process is respectively got in front and back;

Step 3: by what obtain with threshold value T _icompare, wherein wherein when a kth analyzing spot meets time, this kth analyzing spot is defined as the separation of this scanning single line;

Wherein, the lower limb of the set of the separation of all laser scanning single lines of target heap body corresponding target heap body.

2. determine the method for piling body lower limb based on laser scanning single line as claimed in claim 1, it is characterized in that, wherein the span of N is 10 < N < 20.

3. determine based on laser scanning single line the device piling body lower limb, it is characterized in that, comprising:

Laser scanner, the volume coordinate P of analyzing spot on the laser scanning single line obtaining target heap body _i=[X _i, Y _i, Z _i], wherein P _ibe i-th analyzing spot, i=1,2,3 ..., n;

Computing module, for calculating according to following formula

${\stackrel{\&OverBar;}{h}}_{-}={\stackrel{\&OverBar;}{Z}}_{N-}-Z_i$

${\stackrel{\&OverBar;}{h}}_{+}=Z_i-{\stackrel{\&OverBar;}{Z}}_{N+}$

${\stackrel{\&OverBar;}{d}}_i={\stackrel{\&OverBar;}{h}}_{-}-{\stackrel{\&OverBar;}{h}}_{+}$

Wherein, with be respectively at P _ithe mean value of the Z coordinate obtained after N number of analyzing spot carries out windowing process is respectively got in front and back;

Threshold process module, for calculated threshold

Separation determination module, by what obtain with threshold value T _icompare, wherein wherein when a kth analyzing spot meets time, this kth analyzing spot is defined as the separation of this scanning single line;

Heap body lower limb processing module, the separation for all laser scanning single lines according to target heap body forms the lower limb of target heap body.

4. determine based on laser scanning single line the device piling body lower limb as claimed in claim 3, it is characterized in that, wherein the span of N is 10 < N < 20.