Department of Mechanical and Electrical Engineering, Northeast Forestry University, Harbin 150040, China.
Comba Telecom Systems (China) Limited, Guangzhou 510000, China.
Math Biosci Eng. 2021 Sep 9;18(6):7806-7836. doi: 10.3934/mbe.2021388.
The height of standing trees is an important index in forestry research. This index is not only hard to measure directly but also the environmental factors increase the measurement difficulty. Therefore, the measurement of the height of standing trees is always a problem that experts and scholars are trying to improve. In this study, improve fuzzy c-means algorithm to reduce the calculation time and improve the clustering effect, used on this image segmentation technology, a highly robust non-contact measuring method for the height of standing trees was proposed which is based on a smartphone with a fisheye lens. While ensuring the measurement accuracy, the measurement stability is improved. This method is simple to operate, just need to take a picture of the standing tree and determine the shooting distance to complete the measurement. The purpose of the fisheye lens is to ensure that the tree remains intact in the photograph and to reduce the shooting distance. The results of different stability experiments show that the measurement error ranged from -0.196m to 0.195m, and the highest relative error of tree measurement was 3.05%, and the average relative error was 1.45%. Analysis shows that compared with previous research, this method performs better at all stages. The proposed approach can provide a new way to obtain tree height, which can be used to analyze growing status and change in contrast height because of high accuracy and permanent preservation of images.
树木的高度是林业研究中的一个重要指标。这个指标不仅难以直接测量，而且环境因素增加了测量的难度。因此，树木高度的测量一直是专家和学者试图改进的问题。在这项研究中，改进了模糊 c-均值算法以减少计算时间并提高聚类效果，并将其应用于基于带有鱼眼镜头的智能手机的图像分割技术，提出了一种高度稳健的非接触式树木高度测量方法。在保证测量精度的同时，提高了测量的稳定性。该方法操作简单，只需拍摄树木的照片并确定拍摄距离即可完成测量。鱼眼镜头的目的是确保树木在照片中保持完整，并减少拍摄距离。不同稳定性实验的结果表明，测量误差范围在-0.196m 到 0.195m 之间，树木测量的最高相对误差为 3.05%，平均相对误差为 1.45%。分析表明，与之前的研究相比，该方法在各个阶段的表现都更好。该方法可以提供一种新的获取树木高度的方式，由于图像具有高精度和永久性，可以用于分析生长状态和对比高度的变化。
