CN103697826A - Stumpage DBH (diameter at breast height) 6-point measurement method on basis of laser distance measurement - Google Patents

Abstract

The invention relates to a stumpage DBH (diameter at breast height) 6-point measurement method on the basis of laser distance measurement, which relates to a forest resource investigation method. The method comprises the following steps of adopting a stumpage DBH measurement system formed by a working table (1), supporting legs (4), connecting blocks (6) and six laser distance measuring instruments (2) arranged on the same periphery of the working table (1) to respectively measure distances between the six laser distance measuring instruments (2) and the surface of a measured stumpage by utilizing the six laser distance measuring instruments (2) so as to calculate coordinates of six measured points on the surface of the stumpage; carrying out ellipse fitting on the six measured points by adopting a least square ellipse fitting method, and after fitting, obtaining the DBH of the measured stumpage, i.e. half of the sum of a long diameter and a short diameter of an obtained ellipse. The stumpage DBH 6-point measurement method on the basis of laser distance measurement, which is disclosed by the invention, considers that only a smaller proportion of cross sections of stumpages are of a standard round shape, but most of the cross sections of the stumpages are of an oval shape, and thus, the measurement method improves stumpage DBH measurement accuracy.

Description

The standing tree diameter of a cross-section of a tree trunk 1.3 meters above the ground 6 point measurement methods based on laser ranging

Technical field

The invention belongs to forest and measure and detection technique field, be specifically related to a kind of standing tree diameter of a cross-section of a tree trunk 1.3 meters above the ground 6 point measurement methods based on laser ranging.

Background technology

The important component part of forest reserves National Nature resource, its formulation that can be forest resource sustainable development and national forestry development strategy provides decision-making foundation.The diameter of a cross-section of a tree trunk 1.3 meters above the ground is one of element factor of measuring of standing tree, traditional tree breast diameter survey method is to adopt tree breast diameter survey to enclose chi or caliper scale, and operating process is subject to environment and human factor impact, and error is large, in operation, need manually to read, record data, and be not easy to statistics and the management of data.

Beijing Forestry University has proposed standing tree tree breast diameter survey method (the king's allusion quotation based on optics similar triangles method, Wang Jianli etc., standing tree tree breast diameter survey method based on optics similar triangles method, Chinese patent: 201210451967.2, standing tree diameter measurer (Cheng Pengle 2013-2-13) with based on laser ranging and image technique, in Wenhua, standing tree diameter measurer based on laser ranging and image technique, Chinese patent: 201310139213.8, 2013-4-22), the common weak point of these two kinds of methods is: all give tacit consent to standing tree transversal section for circular, and that actual 97.3% standing tree transversal section is approximately is oval (Ma Yan. log and sawn timber modeling and quadrature theory, Harbin, publishing house of Northeast Forestry University, 1996), therefore diameter of a cross-section of a tree trunk 1.3 meters above the ground using oval major diameter or minor axis as standing tree likely all in above-mentioned two kinds of method actual measurements, thereby caused measuring error larger.

Feature of the present invention and technique effect: the standing tree diameter of a cross-section of a tree trunk 1.3 meters above the ground 6 point measurement methods based on laser ranging are circular with respect to traditional detection acquiescence standing tree transversal section, the present invention adopts ellipse to come matching standing tree transversal section more to meet standing tree transversal section actual conditions, thereby this measuring method has improved standing tree tree breast diameter survey precision.

Summary of the invention

The object of the invention is to overcome the deficiency of above-mentioned existing standing tree tree breast diameter survey method, proposed a kind of standing tree diameter of a cross-section of a tree trunk 1.3 meters above the ground 6 point measurement methods based on laser ranging, that the method for the method by 6 fitted ellipse come is convenient, measure accurately the standing tree diameter of a cross-section of a tree trunk 1.3 meters above the ground.

The present invention realizes by concrete technical scheme once:

The invention provides a kind of standing tree diameter of a cross-section of a tree trunk 1.3 meters above the ground 6 point measurement methods based on laser ranging, said method comprising the steps of:

The angle theta on step 1, adjusting supporting leg (4) and ground, make 6 laser range finders (2) of above installing at worktable (1) in the high surface level of ground 1.3m, regulating the position of laser range finder (2) on worktable (1) to make adjacent laser optical path (3) angle is 60 °;

Step 2, record respectively the distance di (i=1,2,3,4,5,6) on 6 laser range finders (2) and standing tree surface;

Step 3, the central coordinate of circle of 6 laser range finders (2) place circumference is made as to initial point O(0,0), because the diameter D of the circumference at laser range finder (2) place is known, the di recording by D and step 2 (i=1,2,3,4,5,6), try to achieve the coordinate (x of tested 6 points in standing tree (5) surface _i, y _i) (i=1,2,3,4,5,6);

Step 4,6 the somes employing least square ellipses matching to above-mentioned measured standing tree (5) surface;

Half of step 5, matching gained major diameter and minor axis sum is the diameter of a cross-section of a tree trunk 1.3 meters above the ground size of tested standing tree (5).

Accompanying drawing explanation

Fig. 1 is the standing tree diameter of a cross-section of a tree trunk 1.3 meters above the ground 6 point measurement method system diagrams based on laser ranging;

1. worktable 2. laser range finder 3. laser optical path 4. supporting leg 5. standing tree 6. contiguous blocks in figure

Fig. 2 is that the standing tree diameter of a cross-section of a tree trunk 1.3 meters above the ground 6 point measurement methods based on laser ranging detect schematic diagram;

1. worktable 2. support 3. laser optical path 5. standing tree in figure

Embodiment

Specific implementation method of the present invention provides a kind of standing tree diameter of a cross-section of a tree trunk 1.3 meters above the ground 6 point measurement methods based on laser ranging, and described system as shown in Figure 1, comprises the following steps:

The angle theta on step 1, adjusting supporting leg (4) and ground, make 6 laser range finders (2) of above installing at worktable (1) in the high surface level of ground 1.3m, regulating the position of laser range finder (2) on worktable (1) to make adjacent laser optical path (3) angle is 60 °;

Step 2, record respectively the distance di (i=1,2,3,4,5,6) on 6 laser range finders (2) and standing tree (5) surface;

The di that this step is surveyed (i=1,2,3,4,5,6) as shown in Figure 2.

Step 3, suppose that the central coordinate of circle of 6 laser range finders (2) place circumference is initial point (0,0), because the diameter of phi D of the circumference at laser range finder (2) place is known, the di (i=1,2,3 that by Φ D and step 2, record, 4,5,6), can try to achieve the coordinate (x of tested 6 points in standing tree (5) surface _i, y _i) (i=1,2,3,4,5,6);

In this step, the coordinate of 6 tested points is tried to achieve by following formula:

Step 4, standing tree (5) surperficial 6 points measured to step 3 adopt least square ellipse matching;

The concrete least square ellipse fit procedure of this step is: the elliptic equation of supposing general type is: Ax ²+ Bxy+Cy ²+ Dx+Ey+1=0, directly by 6 some x on the measured standing tree surface of step 3 _i, y _i) (i=1,2,3,4,5,6) employing principle of least square, corresponding to asking objective function $F(A,B,C,D,E)=\underset{i=1}{\overset{6}{\mathrm{\Σ}}}{({\mathrm{Ax}}^2+\mathrm{Bxy}+{\mathrm{Cy}}^2+\mathrm{Dx}+\mathrm{Ey}+1)}^2$ Minimum value, then by extremum principle, want to make F minimum, must have

solve this system of equations and just can obtain each coefficient A in equation, B, C, D, E, completes 6 points on the measured standing tree surface of step 3 is adopted to least square ellipse matching.Wherein after matching, the center of gained ellipse can be tried to achieve by following formula:

x _c=(BE-2CD)/(4AC-B ²)

y _c=(BD-2AE)/(4AC-B ²)

Oval major axis a and the length of minor axis b are tried to achieve by following formula:

$a=2\sqrt{\frac{2({\mathrm{Ax}}_c^2+{\mathrm{Cy}}_c^2+{\mathrm{Bx}}_c{y}_c-1)}{A+C-\sqrt{{(A-C)}^2+B^2}}}$

$b=2\sqrt{\frac{2({\mathrm{Ax}}_c^2+{\mathrm{Cy}}_c^2+{\mathrm{Bx}}_c{y}_c-1)}{A+C+\sqrt{{(A-C)}^2+B^2}}}$

After step 5, above-mentioned matching, half of gained major diameter and minor axis sum is the diameter of a cross-section of a tree trunk 1.3 meters above the ground size of tested standing tree (5);

The computation process that this step is concrete is: setting up wooden diameter of a cross-section of a tree trunk 1.3 meters above the ground is R, and R is by formula

try to achieve, wherein a and b are respectively oval major axis and the minor axis that step 4 is tried to achieve.

Claims (4)

1. the 6 point measurement methods of the standing tree diameter of a cross-section of a tree trunk 1.3 meters above the ground based on laser ranging, is characterized in that, described measuring method comprises the steps:

The angle theta on step 1, adjusting supporting leg (4) and ground, make 6 laser range finders (2) of above installing at worktable (1) in the high surface level of ground 1.3m, regulating the position of laser range finder (2) on worktable (1) to make adjacent laser optical path (3) angle is 60 °;

Step 2, record respectively the distance di (i=1,2,3,4,5,6) on 6 laser range finders (2) and standing tree (5) surface;

Step 3, the central coordinate of circle of 6 laser range finders (2) place circumference is made as to initial point O(0,0), because the diameter D of the circumference at laser range finder (2) place is known, the di recording by D and step 2 (i=1,2,3,4,5,6), try to achieve the coordinate (x of tested 6 points in standing tree (5) surface _i, y _i) (i=1,2,3,4,5,6);

Step 4,6 the somes employing least square ellipses matching to above-mentioned measured standing tree (5) surface;

Half of step 5, matching gained major diameter and minor axis sum is the diameter of a cross-section of a tree trunk 1.3 meters above the ground size of tested standing tree (5).

2. a kind of standing tree diameter of a cross-section of a tree trunk 1.3 meters above the ground 6 point measurement methods based on laser ranging according to claim 1, it is characterized in that, described in step 2, the central coordinate of circle of 6 laser range finders (2) place circumference is made as to initial point (0,0), try to achieve the coordinate (x of tested 6 points in standing tree (5) surface _i, y _i) (i=1,2,3,4,5,6), in this step, the coordinate of 6 tested points is tried to achieve by following formula:

3. a kind of standing tree diameter of a cross-section of a tree trunk 1.3 meters above the ground 6 point measurement methods based on laser ranging according to claim 1, it is characterized in that, described in step 4,6 points on measured standing tree (5) surface are adopted to least square ellipse matching, the concrete least square ellipse fit procedure of this step is:

The elliptic equation of supposing general type is: Ax ²+ Bxy+Cy ²+ Dx+Ey+1=0, directly by 6 point (x on the measured standing tree surface of step 3 _i, y _i) (i=1,2,3,4,5,6) employing principle of least square, corresponding to asking objective function minimum value, then by extremum principle, want to make F minimum, must have

solve this system of equations and just can obtain each coefficient A in equation, B, C, D, E, completes 6 points on the measured standing tree surface of step 3 is adopted to least square ellipse matching.Center (the x of gained ellipse after matching wherein _c, y _c) can be tried to achieve by following formula:

x _c=(BE-2CD)/(4AC-B ²)

y _c=(BD-2AE)/(4AC-B ²)

Oval major axis a and the length of minor axis b are tried to achieve by following formula:

。

4. a kind of standing tree diameter of a cross-section of a tree trunk 1.3 meters above the ground 6 point measurement methods based on laser ranging according to claim 1, half that it is characterized in that described in step 5 gained major diameter and minor axis sum after matching is the diameter of a cross-section of a tree trunk 1.3 meters above the ground size of tested standing tree (5), and the computation process that this step is concrete is:

Setting up the diameter of a cross-section of a tree trunk 1.3 meters above the ground of wood (5) is R, and R is by formula

try to achieve, wherein a and b are respectively oval major axis and the minor axis that step 4 is tried to achieve.

Images