Abstract:The object was to solve the problems of large tree height measurement errors in forest resources surveys, difficulties in measuring tree heights in complex forest stands, and measurement of the height of tilted stands, etc., and surveying, forest measurement, electronic information technology, sensor technology and image processing technology were focused on. Based on this, a handheld precision standing tree height measurement device was developed. The device consisted of a central processing unit, a laser range finder, a high-definition camera, a high-precision gyro sensor, a liquid crystal display, a memory and the like, and a laser-ranging sensor was used to obtain a distance between the measuring device and the root of tree, and the device was acquired at the same time. The elevation angle information was used to determine the position of the treetop after the image center was used to obtain the second elevation angle information, and the measurement tree height was solved by the distance information and the angle information. The equipment was used to measure the trunk inclination angle of the tree trunk. For the dry-bending trees, edge detection algorithm was used to identify the edges of the image trunk contour. Contour extraction method was used to extract edge points of the trunk contour, and coordinate information of the discrete points on the edge of the trunk was obtained to perform linear fitting. The slope of the straight line was converted to the angle of the trunk, and the angle compensation algorithm was used to complete the measurement of growth of trees with long slopes and standing trees. The test results showed that the tree height measurement accuracy can reach 98.04%, and the inclined standing wood measurement accuracy was 96.89%, which can meet the accuracy requirements of the national forest resource survey. The measuring method of tree height measurement device and the measuring method of high growth and volume of the inclined standing timber can provide new ideas for the research of forestry equipment.
