手持式精准立木树高测量装置设计与试验

Design of Handheld Precision Standing Tree Height Measurement Device

为解决森林资源调查中树高测量误差大,复杂林分环境树高测量难,倾斜立木树干长度测量不准等问题,以测量学、测树学、电子信息技术、传感器技术和图像处理技术为基础,研制了手持式精准立木树高测量装置。该装置集成了中央处理器、激光测距仪、高清摄像头、高精度陀螺仪传感器、液晶显示屏、存储器等元器件,利用激光测距传感器获取测量装置与被测树根间的距离,同时获取该装置的仰角信息,再利用图像中心确定树顶位置后获取第2个仰角信息,通过距离信息和角度信息解算测量树高。使用设备贴紧树干测量树干倾斜角度,对于干型弯曲的树木,利用边缘检测算法识别图像树干轮廓边缘,以轮廓近似法提取树干轮廓边缘点,获得树干边缘离散点坐标信息,将线性拟合求得的直线斜率转换为树干倾斜角,利用角度补偿算法完成长势倾斜立木的树长测量。试验结果表明树高测量精度可达98. 04%,倾斜立木测量精度为96. 89%,满足国家森林资源调查的精度要求。

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.