Extraction of Citrus Trees from UAV Remote Sensing Imagery Using YOLOv5s and Coordinate Transformation

Abstract

Obtaining the geographic coordinates of single fruit trees enables the variable rate application of agricultural production materials according to the growth differences of trees, which is of great significance to the precision management of citrus orchards. The traditional method of detecting and positioning fruit trees manually is time-consuming, labor-intensive, and inefficient. In order to obtain high-precision geographic coordinates of trees in a citrus orchard, this study proposes a method for citrus tree identification and coordinate extraction based on UAV remote sensing imagery and coordinate transformation. A high-precision orthophoto map of a citrus orchard was drawn from UAV remote sensing images. The YOLOv5 model was subsequently used to train the remote sensing dataset to efficiently identify the fruit trees and extract tree pixel coordinates from the orchard orthophoto map. According to the geographic information contained in the orthophoto map, the pixel coordinates were converted to UTM coordinates and the WGS84 coordinates of citrus trees were obtained using Gauss–Krüger inverse calculation. To simplify the coordinate conversion process and to improve the coordinate conversion efficiency, a coordinate conversion app was also developed to automatically implement the batch conversion of pixel coordinates to UTM coordinates and WGS84 coordinates. Results show that the Precision, Recall, and F1 Score for Scene 1 (after weeding) reach 0.89, 0.97, and 0.92, respectively; the Precision, Recall, and F1 Score for Scene 2 (before weeding) reach 0.91, 0.90 and 0.91, respectively. The accuracy of the orthophoto map generated using UAV remote sensing images is 0.15 m. The accuracy of converting pixel coordinates to UTM coordinates by the coordinate conversion app is reliable, and the accuracy of converting UTM coordinates to WGS84 coordinates is 0.01 m. The proposed method is capable of automatically obtaining the WGS84 coordinates of citrus trees with high precision.

Detecting and Mapping Individual Fruit Trees in Complex Natural Environments via UAV Remote Sensing and Optimized YOLOv5

“…This complex natural background may have increased the difficulty of IPT detection. Nevertheless, our model also has high accuracy metrics, even greater than those of Yuan et al [49] and Tian et al [67]. Therefore, our optimized YOLOv5s model has strong performance and is suitable for IPT detection.…”

“…Several other works detected citrus trees, which have crowns similar to those of pomelo trees, using the connectedcomponents labeling (CCL) algorithm [66], Mask R-CNN [48], and YOLOv5s [67] based on high-resolution UAV images. These methods (Table IX) all demonstrated high accuracy, indicating the feasibility of using different algorithms for IFT detection tasks.…”

“…These methods (Table IX) all demonstrated high accuracy, indicating the feasibility of using different algorithms for IFT detection tasks. Donmez et al [66] and Tian et al [67] used citrus tree images without interference from other trees for training and validation, which are relatively simple object detection tasks. Our proposed model, FruitNet, was trained and validated on the IPTIS dataset, which consists of many images in which pomelo trees coexist with other trees, crops, roads, ponds, villages (houses), and overhead power lines.…”

Design and validation of a multi-objective waypoint planning algorithm for UAV spraying in orchards based on improved ant colony algorithm

“…However, this method is suitable for obtaining large-scale farmland data, and is not suitable for extracting geographic coordinate information of a single fruit tree. Tian et al (2022) proposed a method for extracting citrus tree coordinates based on YOLOv5s. First, an orchard orthophoto map is drawn using a remote sensing dataset.…”

Koordinat Dönüşüm Parametrelerinin Uygulama Alanı Dışında Uygunluğunun Araştırılması

“…Farklı datumlardaki koordinat sistemlerinin ortak projelerde kullanılabilmesi için farklı sistemlerin birbirleriyle ilişkilendirilmesi ve birbirlerine dönüştürülmesi gerekmektedir (Turgut & İnal, 2003). Koordinat dönüşümü mevcut ortak noktaların koordinat bilgilerini kullanarak farklı koordinat sistemleri arasında geçiş yapma işlemidir (Tian et al, 2022). Koordinat dönüşümü işlemi için her iki sistem arasında bazı matematiksel ilişkilerin tanımlanmış olması gerekmektedir.…”