手持式树径自动识别测树仪的研制与应用

A handheld dendrometer for automatic tree diameter measurement

在森林资源调查中需要调查林分因子,从而了解森林资源的数量与质量,以进行森林资源的规划、设计和经营。森林资源调查是一项费时费力的工作,使用传统测量工具需要不同仪器来进行测量,同时还受地形条件的限制。为快速精确地进行林木测量,开发设计了便携式数字化智能测树仪。仪器由STM32F103VET6单片机、ov9655传感器、LIS331DLTR倾角传感器、键盘等及其相关电路模块构成。采用相位原理测距,具有±1.5 mm的测距精度。在径高同测模式下,利用摄像头和互补金属氧化物半导体(CMOS)传感器对图像进行处理,能够实现树径的自动识别,再利用所测距离和倾角,实现高度、直径同步测量。仪器还有测径模式,测高模式,测距模式,倾角测量模式,面积计算模式。经实验验证,测径模式下,胸径的平均误差为-0.05 cm,误差在0.50 cm之内的占97.6%。在不同距离下,对不同高度的直径进行测量表明,在最佳距离内可使误差在0.50 cm内。该便携式数字化智能测树仪可满足森林资源调查需求,实现林业数字化。

In a Forest Resource Inventory, a time-consuming job traditionally requiring different instruments indifficult terrain conditions, stand factors are determined to understand the quantity and quality of forest resources,thereby enhancing forest planning, designing and operation. To enable fast and accurate tree measurement,a portable digital intelligent dendrometer was designed and developed. This instrument consisted of aSTM32F 103VET6 microcontroller, an ov9655 sensor, a LIS331DLTR angle sensor, a keyboard, laser rangingsensors, monitors, a power supply, and the relevant circuit module. Ranging used the phase principle with aranging accuracy of $ 1.5 mm. In the simultaneous measurement mode for diameter and height, the diameter ofthe tree was automatically identified through image processing with a camera and a complementary metal-oxidesemiconductor（CMOS） sensor. In addition, the following modes were present, caliper, mode, distance measurement,angle measurement and area calculation. Experimental results showed that in the caliper mode, theaverage DBH error was -0.05 cm, and the error within 0.5 cm accounted for 97.61. Diameter measurements atdifferent distances and different heights showed that the error fot the optimum distance was within 0.5 cm.Thus, this instrument with automated measurements could meet the needs of a forest resource survey team.