Abstract:In order to realize the rapid and accurate determination of diameter at breast height (DBH), EAN-13 bar code encoding and decoding rules was taken as template, based on the Android platform and Open CV intelligent image processing technology, an electronic bar code ruler was designed and implemented to realize the automatic measurement of the tree DBH size by single operation. When the bar code encoding was completed, bar code image was scanned by using mobile phone APP, through image preprocessing, bar code identification, location and diameter automatic measurement and recording, data storage and export process, the automatic measurement of DBH in forest survey was realized. By selecting 205 samples of coniferous trees and 200 broadleaf trees, the electronic bar code was used to measure them, at the same time, the measurement results were compared with the precision of the traditional measuring ruler. The experimental results showed that the measurement accuracy of the method can be more than 99.95%, which can meet the precision requirements of continuous logging of national forest resources. Meanwhile, the method of measuring tree breast diameter of each tree was only 11 to complete the work of measuring diameter, and the measuring work efficiency was greatly increased. This method had good application prospect of the tree DBH measurement in forest survey.