Fisheye Image Detection of Trees Using Improved YOLOX for Tree Height Estimation

• DOI: 10.3390/s22103636
• Publication Date: 2022-05-11T01:52:11Z
• Authors: Jiayin Song; Yue Zhao; Wenlong Song; Hongwei Zhou; Di Zhu; Qiqi Huang; Yiming Fan; Chao Lu
• Keywords: tree height estimation; Chemical technology; equidistant projection; deep learning; Forestry; TP1-1185; 02 engineering and technology; 15. Life on land; Article; tree height estimation; equidistant projection; deep learning; fisheye image; Trees; fisheye image; 0202 electrical engineering, electronic engineering, information engineering

Tree height is an essential indicator in forestry research. This indicator is difficult to measure directly, as well as wind disturbance adds to the measurement difficulty. Therefore, tree height measurement has always been an issue that experts and scholars strive to improve. We propose a tree height measurement method based on tree fisheye images to improve the accuracy of tree height measurements. Our aim is to extract tree height extreme points in fisheye images by proposing an improved lightweight target detection network YOLOX-tiny. We added CBAM attention mechanism, transfer learning, and data enhancement methods to improve the recall rate, F1 score, AP, and other indicators of YOLOX-tiny. This study improves the detection performance of YOLOX-tiny. The use of deep learning can improve measurement efficiency while ensuring measurement accuracy and stability. The results showed that the highest relative error of tree measurements was 4.06% and the average relative error was 1.62%. The analysis showed that the method performed better at all stages than in previous studies.