Stumpage Measurement Method Using Machine Vision And Laser Measurement

In this paper,to meet the algorithm requirements of the handheld dendrometer developed independently,an algorithm path using image processing technology and machine vision technology with stumpage image from CMOS was establish for trunk diameter pixel number calculation.And diameter at breast height(DBH),upper diameter,diameter height,tree height,crown width and tree volume were obtained combining the measurement parameters by sensor.The details as follows:(1)The extraction of two sides distance of trunk in the digital image was realized.Edge features of stumpage were extracted by edge detection operator,and mapped to parameter space by Hough transform,which achieved straight line extraction of trunk sides combined with conditions filter.And pixel distances of trunk sides on central pixel line were extracted according to straight line parameters.A method of convolving the maximum connected region after binarization and inversion of the original image with edge feature was proposed,which can remove the background edge in a degree.(2)A comparison experiment of different edge detection operators and Gaussian filter standard deviations was performed for the effects of trunk edge detection and straight line extraction.Comparing the effect of five kinds of edge detection operators on the stumpage image,Canny operator has better detection rate and accuracy.Edge detection and pixel number calculations was performed on image with Gaussian filtering processing with Sigma of 0.1,0.3,1.4 and 3,which showed that the edge of trunk recognition had a smaller deviation when Sigma was in 0.3?1.4.(3)Tree height and crown width were measured through the parameters acquired by sensor,and DBH,upper diameter and volume were calculated combining the obtained pixel diameter of the trunk.Verifying the accuracy of the measurement method,the measurement of DBH,tree height,and crown width have a high degree of fit to the true value.At different measuring distances and inclination angles,absolute error of DBH measurement was within ±4cm,and relative error was within±6.00%;absolute error of upper diameter measurement was from-1.5 to 0.8cm,and relative error was from-15.25%to 16.95%;middle error of the diameter height measurement was 0.005m,and maximum absolute error was-0.01m;absolute error of tree height measurement was from-1.510 to 3.386m,and relative error was from-9.10%to 27.09%;absolute error of crown width measurement was from-0.300 to 0.260m,and relative error was from-6.75%to 3.50%;absolute error of the volume solution was from-0.000105m3 to 0.001598m3,and relative error was from-0.44%to 1.95%.