融合激光和机器视觉的立木胸径检测方法

Measuring Diameters at Breast Height Using Combination Method of Laser and Machine Vision

为了提高立木胸径检测的效率,解决图像法测量立木胸径中的标定问题,提出了融合激光和机器视觉的立木胸径检测方法。将激光光束进行扩束准直后照射到立木树干上,采用树干上的激光光斑作为标尺进行图像测量。通过Otsu法对激光光斑进行分割,根据激光光斑的实际尺寸和像素数确定图像上立木胸径的位置,根据立木胸径的像素数计算出立木胸径值。试验结果表明,所提方法的测量结果与轮尺测量的胸径值最大误差1.22%,符合国家对森林资源清查操作的误差要求。

The application of digital photographic method in the forest has shown great potential for improving the accuracy and efficiency. Image acquired with acommercially available digital camera were used to make measurements on 10 Platanus orientalis stems. Laser spot was used as scale instead of pole. The laser spot was extracted from the background by the 2-1） Otsu algorithm. Error studies showed that the laser spot should be set at 1.3 m high to improve the measurement accuracy. The accuracy of this method for measuring diameters at breast height was tested by comparing the results with those obtained from caliper. The comparison showed that the photographic method provided a good assessment of standing tree diameters at breast height and the maximum error was 1.22%.