The Tree Height Measurement Method Based On Smartphone

Based on the key problems in the application of stumpage height measurement method in the existing research,this paper takes the smart phone in the intelligent terminal as the equipment foundation,starts with the collected single stand tree image,and aims at the measuring method of the standing tree height.Combined with camera calibration technology,machine vision technology and digital image processing technology.In this paper,the measurement of stand height is studied from two aspects: single plant and multiple tree,and the following work has been done.In the aspect of height measurement of single stand tree:(1)According to the structure characteristics of the camera of the smartphone,the nonlinear distortion correction model of the characteristics of the camera of the mobile phone is used to calibrate the camera in the smartphone in order to obtain the inner part of the camera of the mobile phone.External parameters.(2)the mobile phone takes samples of standing wood images,carries out feature selection,denoising processing and image contour extraction,then,The region of interest in the standing tree image is obtained by the threshold mutation three-point method.(3)A method for measuring the height of standing tree based on the perspective distortion correction model based on point operation is proposed.Calculation of the physical size of unit pixels in smartphone images in 3D world coordinates.(4)The help of the pixel value of the vertical maximum point obtained from the acquisition of the image,combined with the actual horizontal distance of the standing tree to be measure.(5)In the experiment of measuring the height of a single tree,12 samples in different environments were selected and 12 experiments were carried out,the accuracy of which was less than 93.55%.In the aspect of measuring the height of several standing trees:(1)The image correction is carried out on the sampling samples,and then the image is de-noised and the contour is extracted by adjusting the salience analysis chart.The pixel information of vertical maximum point of standing tree is identified and obtained.(2)Using image segmentation processing,using grayscale processing and binary processing,The characteristic points of the calibrated objects in the standard stand are identified.(3)The plane coordinate system of the standard stand and thecalculation model of the height of the standard stand are established by the vanishing point algorithm.(4)The pixels of the image neutral wood are analyzed.An Information extraction Model of standing Wood depth based on Imaging Angle of object and rotation Angle of camera.(5)According to the relationship between the height and depth of several trees to be measured,Establish several stand height measurement models.(6)In the precision experiment of measuring the height of many trees: using the same mobile phone camera to select a total of 20 samples in different environments,carry out 7 shooting experiments to obtain experimental data.Compared with the true value,the accuracy is 95.13%.(7)The measuring method of the height of several standing trees is obtained by taking individual images of multiple standing trees,which improves the measuring efficiency of the forest surveyors.