CN102927921A - Stumpage breast height diameter measuring method based on optics similar triangle method - Google Patents

Abstract

The invention provides a stumpage breast height diameter measuring method based on an optics similar triangle method. The stumpage breast height diameter measuring method based on the optics similar triangle method relates to forest measurement and includes the following steps: a camera and a laser are used to create a stumpage breast height diameter measuring system; the camera is used to take photos of a to-be-tested stumpage to obtain images of the stumpage; and after the shot images of the stumpage are preprocessed, a point, namely a laser spots falling on a phase plane, (X', Y') is obtained. According to an optics similar triangle principle, the point (X', Y' ) that the laser spot falls on the phase plane carries out coordinate transformation towards a three-dimensional space to obtain a point (X, Y, Z). The point (X, Y, Z) projects towards a horizontal direction to obtain a point (X projection, Y projection) after being processed. A least square circle fitting method is adopted to carry out circle fitting on the point(X projection, Y projection), and then a round radius parameter after fitting is a breast height diameter of the to-be-tested stumpage. The stumpage breast height diameter measuring method based on the optics similar triangle method has the advantages that algorithm can be realized easily and can measure the stumpage breast height diameter quickly in non-contact mode.

Description

Standing tree tree breast diameter survey method based on optics similar triangles method

Technical field

The present invention relates to forest and measure, relate in particular to a kind of standing tree tree breast diameter survey method based on optics similar triangles method.

Background technology

Forest reserves is the important component part of National Nature resource, and its growth and decline dynamically are the outstanding features of economy of forestry benefit, also is to formulate the foundation of felling incubation program.Traditional forest forest tree breast diameter survey method is the diameter scale as adopting tree breast diameter survey to enclose chi or caliper scale with length transition, thereby carries out the estimation of the forest diameter of a cross-section of a tree trunk 1.3 meters above the ground, affected greatly by environment and human factor, and resultant error is very big.In order to address the above problem, the inventor provides a kind of standing tree tree breast diameter survey method based on optics similar triangles method.

Summary of the invention

In view of the needs of above-mentioned the deficiencies in the prior art and practical application, the invention provides a kind of standing tree tree breast diameter survey method based on optics similar triangles method, realize Simple fast, contactless standing tree tree breast diameter survey.

The present invention realizes by following concrete technical scheme:

The invention provides a kind of standing tree tree breast diameter survey method based on optics similar triangles method, said method comprising the steps of:

Step 1, captured standing tree image is carried out pre-service, extract the laser facula skeleton part of single pixel after, obtain described laser facula at the point of phase plane (X ', Y ');

Step 2, according to the optics similar triangle theory, the point (X ', Y ') that above-mentioned laser facula is dropped on phase plane carries out coordinate conversion to three dimensions and obtains point (X, Y, Z);

Step 3, above-mentioned gained three dimensions point (X, Y, Z) processed after, carry out projection invocation point (X to horizontal direction _Throw, Y _Throw); Adopt the least square circle approximating method to point (X _Throw, Y _Throw) justify match;

Gained radius of circle parameter is the diameter of a cross-section of a tree trunk 1.3 meters above the ground size of tested standing tree after step 4, the above-mentioned match;

According to optical triangulation theory, the coordinate points (X ', Y ') that laser facula is dropped on phase plane is carried out coordinate conversion to three dimensions and is obtained point (X, Y, Z) and comprising described in the step 2:

By following formula:

Realize that the coordinate points (X ', Y ') of standing tree image phase plane is to the conversion of three-dimensional coordinate points (X, Y, Z); Wherein, f is the focal length in the experimental facilities, b be lasing light emitter to the distance of camera optical axis, θ is optical plane and the COMS plane angle that lasing light emitter penetrates.

Adopt the least square circle approximating method to point (X described in the step 3 _Throw, Y _Throw) carry out match and comprise that (adopt X in the following principle derivation formula, Y expresses X _Throw, Y _Throw):

Order:

$C=(\mathrm{N\Σ}{X}_i^2-\mathrm{\Σ}{X}_i\mathrm{\Σ}{X}_i)$

$D=(\mathrm{N\Σ}{X}_i{Y}_i-\mathrm{\Σ}{X}_i\mathrm{\Σ}{Y}_i)$

$E=\mathrm{N\Σ}{X}_i^3+\mathrm{N\Σ}{X}_i{Y}_i^2-\mathrm{\Σ}(X_i^2+Y_i^2)\mathrm{\Σ}{X}_i$

$G=(\mathrm{N\Σ}{Y}_i^2-\mathrm{\Σ}{Y}_i\mathrm{\Σ}{Y}_i)$

$H=\mathrm{N\Σ}{X}_i^2{Y}_i+\mathrm{N\Σ}{Y}_i^3-\mathrm{\Σ}(X_i^2+Y_i^2)\mathrm{\Σ}{Y}_i$

By

$a=\frac{\mathrm{HD}-\mathrm{EG}}{\mathrm{CG}-D^2}$

$b=\frac{\mathrm{HC}-\mathrm{ED}}{D^2-\mathrm{GC}}$

$c=\frac{\mathrm{\Σ}(X_i^2+Y_i^2)+\mathrm{a\Σ}{X}_i+\mathrm{b\Σ}{Y}_i}{N}$

:

$A=-\frac{a}{2}$

$B=-\frac{b}{2}$

$R=\frac{1}{2}\sqrt{a^2+b^2-4c}$

Realize the Least Square Circle match; A wherein, b, c is the coefficient of circle general equation, C, D, E, G, H are the intermediate computations parameter, N be that all unique points are total.

Characteristics of the present invention and technique effect:

Can be found out by above-mentioned a kind of standing tree tree breast diameter survey method based on optics similar triangles method, the present invention is by realizing that phase plane coordinate points (X ', Y ') is to three dimensional space coordinate point (X, Y, Z) conversion, and adopt the least square circle approximating method to point (X _Throw, Y _Throw) carry out match, thus Simple fast, the contactless actual diameter of a cross-section of a tree trunk 1.3 meters above the ground of the standing tree size that records; Especially in the work that forest is realized measuring in a large number, compare with traditional measuring technique, can reduce to a great extent time and manpower consumption.

Description of drawings

Fig. 1 is standing tree tree breast diameter survey system diagram of the present invention;

Fig. 2 is the process flow diagram of specific implementation method of the present invention;

Fig. 3 is the optics similar triangles method schematic diagram in the specific implementation method of the present invention;

Fig. 4 is the round fitting theory figure in the specific implementation method of the present invention;

Embodiment

Specific implementation method of the present invention provides a kind of standing tree tree breast diameter survey method based on optical triangulation shape method, and described method may further comprise the steps as shown in Figure 1:

Step 1, captured standing tree image is carried out pre-service, extract the laser facula skeleton part of single pixel after, obtain described laser facula at the point of phase plane (X ', Y ');

Standing tree image pre-processing method described in this step comprise image carried out the reduction of G (green) component and B (blueness) component after, the standing tree image is carried out binary conversion treatment; The laser facula skeleton technique that extracts single pixel described in this step comprise to image adopt mathematical morphology rudimentary algorithm---dilation and erosion is realized the refinement of laser facula, then the maximum UNICOM zone by image after the searching refinement removes laser facula skeleton noise spot in addition, thereby obtains the laser facula skeleton part of single pixel.

Step 2, according to the optics similar triangle theory, the point (X ', Y ') that above-mentioned laser facula is dropped on phase plane carries out coordinate conversion to three dimensions and obtains point (X, Y, Z);

Described in this step laser facula is dropped on phase plane point (X ', Y ') is converted to point (X to three dimensions, Y, Z) be by the calculating of deriving of the shape of optical triangulation shown in Fig. 3 principle, obtain formula 1, thus the point coordinate of realization phase plane (X ', Y ') be converted to point (X to three dimensions, Y, Z).

Formula 1I

Wherein, f is the focal length in the experimental facilities, b be lasing light emitter to the distance of camera optical axis, θ is optical plane and the COMS plane angle that lasing light emitter penetrates, (X ', Y ') is the some M ' coordinate of phase plane, (X, Y, Z) is three dimensions point M coordinate;

Step 3, above-mentioned gained three dimensions point (X, Y, Z) processed after, carry out projection invocation point (X to horizontal direction _Throw, Y _Throw); Adopt the least square circle approximating method to point (X _Throw, Y _Throw) justify match;

Three-dimensional point (X, Y, Z) carries out projection invocation point (X to horizontal direction described in this step _Throw, Y _Throw) comprise three dimensions is put the place coordinate plane to the surface level projection, the angle between described surface level and the three dimensions point place coordinate plane is 90 °-θ; The described projection invocation point (X of institute _Throw, Y _Throw) with three dimensions point in (X, Y) between exist as concern:

X _Throw=X

Y _Throw=Ycos (90 °-θ)

Adopt the least square circle approximating method to point (X described in this step _Throw, Y _Throw) justify match and comprise: the least square circle approximating method is the optimal function coupling that finds one group of data by the quadratic sum of least error, can (adopt X in the following principle derivation formula, Y expresses X by following method realization least square circle approximating method _Throw, Y _Throw);

The circular curve equation is:

R ²＝(X-A) ²+(Y-B) ²

Expansion gets:

R ²＝X ²-2AX+A ²+Y ²-2BY+B ²

Order

a＝-2A

b＝-2B

c＝A ²+B ²-R ²

Therefore can get circular curve general equation formula:

X ²+Y ²+aX+bY+c＝0

As long as obtain parameter a, b, c can try to achieve the parameter of center of circle radius:

$A=-\frac{a}{2}$

$B=-\frac{b}{2}$

$R=\frac{1}{2}\sqrt{a^2+b^2-4c}$

Point set (X _i, Y _i) (1,2,3...N) mid point is to distance of center circle from being d for i ∈ _i:

d _i＝(X _i-A) ²+(Y _i-B) ²

Point (X _i, Y _i) to the distance of rounded edge square with the difference of radius squared be:

${\mathrm{\δ}}_i=d_i^2-R^2={(X_i-A)}^2+{(Y_i-B)}^2-R^2=X_i^2+Y_i^2+a{X}_i+b{Y}_i+c$

Make that Q (α, b, c) is δ _iQuadratic sum:

$Q(a,b,c)=\mathrm{\Σ}{\mathrm{\δ}}_i^2=\mathrm{\Σ}{\left[(X_i^2+Y_i^2+a{X}_i+b{Y}_i+c)\right]}^2$

Find the solution parameter a, b, c is so that the value of Q (a, b, c) is minimum gets final product;

Order

$C=(\mathrm{N\Σ}{X}_i^2-\mathrm{\Σ}{X}_i\mathrm{\Σ}{X}_i)$

D＝(N∑X _iY _i-∑X _i∑Y _i)

$E=\mathrm{N\Σ}{X}_i^3+\mathrm{N\Σ}{X}_i{Y}_i^2-\mathrm{\Σ}(X_i^2+Y_i^2)\mathrm{\Σ}{X}_i$

$G=(\mathrm{N\Σ}{Y}_i^2-\mathrm{\Σ}{Y}_i\mathrm{\Σ}{Y}_i)$

$H=\mathrm{N\Σ}{X}_i^2{Y}_i+\mathrm{N\Σ}{Y}_i^3-\mathrm{\Σ}(X_i^2+Y_i^2)\mathrm{\Σ}{Y}_i$

Can solve:

$a=\frac{\mathrm{HD}-\mathrm{EG}}{\mathrm{CG}-D^2}$

$b=\frac{\mathrm{HC}-\mathrm{ED}}{D^2-\mathrm{GC}}$

$c=\frac{\mathrm{\Σ}(X_i^2+Y_i^2)+\mathrm{a\Σ}{X}_i+\mathrm{b\Σ}{Y}_i}{N}$

:

$A=-\frac{a}{2}$

$B=-\frac{b}{2}$

$R=\frac{1}{2}\sqrt{a^2+b^2-4c}$

Gained radius of circle parameter is the diameter of a cross-section of a tree trunk 1.3 meters above the ground size of tested standing tree after step 4, the above-mentioned match;

By the realization of above-mentioned steps, can finish the Quick Measurement of the standing tree diameter of a cross-section of a tree trunk 1.3 meters above the ground; Embodiment provided by the present invention can Simple fast, the contactless standing tree tree breast diameter survey of finishing; Embodiment instantiation flexible form of the present invention, therefore any those of ordinary skill in the art, in the technical scope that the present invention discloses, the conversion that can expect easily or replacement all should be encompassed within the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection domain of claim.

Claims (8)

1. the standing tree tree breast diameter survey method based on optics similar triangles method is characterized in that, described measuring method comprises the steps:

Step 1: captured standing tree image is carried out pre-service, extract the laser facula skeleton part of single pixel after, obtain described laser facula at the point of phase plane (X ', Y ');

Step 2: according to the optics similar triangle theory, the point (X ', Y ') that above-mentioned laser facula is dropped on phase plane carries out coordinate conversion to three dimensions and obtains point (X, Y, Z);

Step 3: after above-mentioned gained three dimensions point (X, Y, Z) processed, carry out projection invocation point (X to horizontal direction _Throw, Y _Throw); Adopt the least square circle approximating method to point (X _Throw, Y _Throw) justify match;

Step 4: gained radius of circle parameter is the diameter of a cross-section of a tree trunk 1.3 meters above the ground size of tested standing tree after the above-mentioned match;

2. described a kind of standing tree tree breast diameter survey method based on optics similar triangles method according to claim 1, it is characterized in that, described in the step 2 according to the optics similar triangle theory, with laser facula drop on phase plane point (X ', Y ') carries out coordinate conversion to three dimensions and obtain point (X, Y, Z) comprising:

By following formula:

Realization is by the conversion of the coordinate points of the phase plane of standing tree image (X ', Y ') to three-dimensional coordinate points (X, Y, Z); Wherein, f is the focal length in the experimental facilities, b be lasing light emitter to the distance of camera optical axis, θ is optical plane and the COMS plane angle that lasing light emitter A penetrates.

3. described a kind of standing tree tree breast diameter survey method based on optics similar triangles method according to claim 2, described with laser facula drop on phase plane point (X ', Y ') carries out coordinate conversion to three dimensions and obtain point (X, Y, the foundation of Coordinate Transformation Models Z) comprises: the foundation of photo coordinate system X ' O ' Y ' is parallel with XOY plane in the three-dimensional system of coordinate, and three-dimensional system of coordinate initial point O passes the camera optical axis position.

4. the foundation of Coordinate Transformation Models according to claim 3 comprises: the position of lasing light emitter A is positioned at the below of camera optical axis.

5. the foundation of Coordinate Transformation Models according to claim 3 comprises: it is just parallel with surface level that lasing light emitter is launched formed laser plane, and optical plane and COMS plane angle θ angle that above-mentioned lasing light emitter A penetrates can be surveyed.

6. described a kind of standing tree tree breast diameter survey method based on optics similar triangles method according to claim 1, it is characterized in that, described in the step 3 to gained three dimensions point (X, Y, Z) process, comprise to the judgement of abnormity point in the three dimensions point (X, Y, Z) and to satisfying the point that coordinate conversion and circle match require and screening.

7. described a kind of standing tree tree breast diameter survey method based on optics similar triangles method according to claim 1 is characterized in that, the three dimensions point (X, Y, Z) in the step 3 after the above-mentioned processing carries out projection invocation point (X to horizontal direction _Throw, Y _Throw), comprising three dimensions is put the place coordinate plane to the surface level projection, the angle between described surface level and the three dimensions point place coordinate plane is 90 °-θ; The described projection invocation point (X of institute _Throw, Y _Throw) with three dimensions point in (X, Y) between exist as concern:

X _Throw=X

Y _Throw=Ycos (90 °-θ).

8. described a kind of standing tree tree breast diameter survey method based on optics similar triangles method according to claim 1 is characterized in that, adopts the least square circle approximating method to point (X _Throw, Y _Throw) justify match and may further comprise the steps that (adopt X in the following principle derivation formula, Y expresses X _Throw, Y _Throw):

Order:

D＝(N∑X _iY _i-∑X _i∑Y _i)

By

:

Realize the Least Square Circle match; A wherein, b, c is the coefficient of circle general equation, C, D, E, G, H are the intermediate computations parameter, N be that all unique points are total.

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