CN104075695A

CN104075695A - Method for observing forest from long distance by super-long focal length camera

Info

Publication number: CN104075695A
Application number: CN201410332360.1A
Authority: CN
Inventors: 冯仲科; 樊仲谋
Original assignee: Beijing Forestry University
Current assignee: Beijing Forestry University
Priority date: 2014-07-11
Filing date: 2014-07-11
Publication date: 2014-10-01

Abstract

The invention discloses a method for measuring the attribute of a forest from a long distance by a super-long focal length digital camera. The method is characterized by comprising the steps of shooting a forest sample plot to be measured for twice respectively at the different heights at an observing point by the 1700mm super-long focal length camera provided with a compass and a global positioning system (GPS), recording the horizontal angle theta and the angle of inclination delta of the camera during shooting, and recording the coordinates X, Y and Z as well as the height h; establishing an image space coordinate system xoz for a corrected photograph, and measuring the image space coordinates xi and yi of points with the same name at the edges of trunks of all individual trees in an observation area; and calculating the object space coordinates of all the points at the edges, and restoring attribute data of the area to be measured.

Description

A kind of method of overlength focal length camera remote observation forest

One, technical field

The present invention relates to a kind of method of using super Telephoto Digital Camera to measure forest at a distance, it is characterized in that: use the burnt camera of 1700mm overlength be equipped with GPS, box compass to obtain at a distance the way of target observation region forest attribute.

Two, technical background

The most popular method of the investigation diameter of a cross-section of a tree trunk 1.3 meters above the ground is every wooden dipping at present, and the brerast-height diatmeter of each strain trees in bioassay standard ground, registers by the grouping of rank, footpath.The class mean of carrying out diameter grouping when rank, so-called footpath are every wooden dipping.The size of group distance is determined according to the difference of standing forest average diameter size.On permanent study plot, the tree diameters of every wooden dipping adopts individual plant measured value to register, and notes down, and every strain trees are numbered, to again make comparisons during investigation (check) not according to the grouping of rank, footpath.

Forest photogrammetry is generally to the mathematics transformation model between object coordinates and image space coordinate with cubic phase, obtain the sample ground tree surveying information of single wood or standing forest, automatically trees seeds, diameter, the height of tree and the relative coordinate of eminence are arbitrarily extracted in identification, and then obtain single wood and the information such as sample ground information comprises the volume of timber, accumulates, biomass, density, rank, footpath density.Set up forest digital photography sample (photograph sample) model, for forest survey indoor and field integration provides new theory and technology and method, but obtaining that cubic phase is right needs harsh s internal and external orientation, often be difficult to obtain smoothly, so the present invention is selected in, use under given conditions single-sheet photo to obtain standing forest diameter of a cross-section of a tree trunk 1.3 meters above the ground information.

Three, summary of the invention

In observation station, respectively at differing heights use with the burnt camera of overlength of the 1700mm of box compass and GPS to forest sample to be measured carry out twice shooting, camera horizontal angle θ during chronophotography, pitch angle δ, coordinate X, Y, Z and height h.Gained digital photo is carried out to camera distortion correction.On digital photo after correction, set up image space coordinate system xoz, measure the mutually square coordinate x of the upper trunk of each Dan Mu edge same place in observation area _i, y _i.

Horizontal angle θ while utilizing twice observation, pitch angle δ, coordinate X, Y, Z and height h, with the mutually square coordinate x of same place _i, y _i, use digital-to-analogue:

\{\begin{matrix} x - x_{0} = - f \frac{a_{1} (X - X_{S}) + b_{1} ({Y - Y}_{S}) + c_{1} (Z - Z_{S})}{a_{3} (X - X_{S}) + b_{3} (Y - Y_{S}) + c_{3} (Z - Z_{S})} \\ x - y_{0} = - f \frac{a_{2} (X - X_{S}) + b_{2} (Y - Y_{S}) + c_{2} (Z - Z_{S})}{a_{3} (X - X_{S}) + b_{3} (Y - Y_{S}) + c_{3} (Z - Z_{S})} \end{matrix}

b ₁＝cosωsinκ

b ₂＝cosωcosκ

b ₃＝-sinω

In formula: k=0, ω=δ

Calculate the object coordinates of all marginal points, reduce area attribute data to be measured.

Four, embodiment:

Research is chosen has typical sample ground data.In the shooting point apart from 1000 meters, sample ground, use the burnt camera of overlength to take standing forest to be measured:

Step 1: in research area, utilize typical sampling method to choose research location, 4 of observation sampling points are set, carry out the every wooden dipping of routine to observing sample.；

Step 2: utilize ordinary digital camera to take on observation sampling point, camera horizontal angle θ during chronophotography, pitch angle δ, coordinate X, Y, Z and height h.。

Step 3: set up image space coordinate system xoz on the digital photo after correction, measure the mutually square coordinate x of the upper trunk of each Dan Mu edge same place in observation area _i, y _i.

Step 4: process conventional every wooden dipping method data record.

1, step 5: the horizontal angle θ while utilizing twice observation, pitch angle δ, coordinate X, Y, Z and height h, with the mutually square coordinate x of same place _i, y _i, use digital-to-analogue:

\{\begin{matrix} x - x_{0} = - f \frac{a_{1} (X - X_{S}) + b_{1} ({Y - Y}_{S}) + c_{1} (Z - Z_{S})}{a_{3} (X - X_{S}) + b_{3} (Y - Y_{S}) + c_{3} (Z - Z_{S})} \\ x - y_{0} = - f \frac{a_{2} (X - X_{S}) + b_{2} (Y - Y_{S}) + c_{2} (Z - Z_{S})}{a_{3} (X - X_{S}) + b_{3} (Y - Y_{S}) + c_{3} (Z - Z_{S})} \end{matrix}

b ₁＝cosωsinκ

b ₂＝cosωcosκ

b ₃＝-sinω

In formula: k=0, ω=δ

Step 6: the contrast every wooden dipping data of conventional method and ordinary digital camera data, analysis precision, obtains conclusion.

Claims

1. the method for an overlength focal length camera remote observation forest, it is characterized in that: in observation station, respectively at differing heights use with the burnt camera of overlength of the 1700mm of box compass and GPS to forest sample to be measured carry out twice shooting, camera horizontal angle θ during chronophotography, pitch angle δ, coordinate X, Y, Z and height h.

2. gained digital photo in step 1 is carried out to camera distortion correction.

On the digital photo after step 2 is corrected, set up image space coordinate system xoz, measure the mutually square coordinate x of the upper trunk of each Dan Mu edge same place in observation area _i, y _i.

3. the horizontal angle θ while utilizing twice observation, pitch angle δ, coordinate X, Y, Z and height h, with the mutually square coordinate x of same place _i, y _i, use digital-to-analogue:

\{\begin{matrix} x - x_{0} = - f \frac{a_{1} (X - X_{S}) + b_{1} ({Y - Y}_{S}) + c_{1} (Z - Z_{S})}{a_{3} (X - X_{S}) + b_{3} (Y - Y_{S}) + c_{3} (Z - Z_{S})} \\ x - y_{0} = - f \frac{a_{2} (X - X_{S}) + b_{2} (Y - Y_{S}) + c_{2} (Z - Z_{S})}{a_{3} (X - X_{S}) + b_{3} (Y - Y_{S}) + c_{3} (Z - Z_{S})} \end{matrix}

b ₁＝cosωsinκ

b ₂＝cosωcosκ

b ₃＝-sinω

In formula: k=0, ω=δ