In a Forest Resource Inventory,a time-consuming job traditionally requiring different instruments in difficult 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 a STM32F103VET6 microcontroller,an ov9655 sensor,a LIS331DLTR angle sensor,a keyboard,laser ranging sensors,monitors,a power supply,and the relevant circuit module.Ranging used the phase principle with a ranging accuracy of ± 1.5 mm.In the simultaneous measurement mode for diameter and height,the diameter of the 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,the average DBH error was-0.05 cm,and the error within 0.5 cm accounted for 97.6％.Diameter measurements at different 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.
关键词
森林测计学/测树仪/传感器/测量/图形识别/立木
Key words
forest mensuration/dendrometer/sensor/measurement/image identification/standing trees
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