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Smart Agriculture ›› 2024, Vol. 6 ›› Issue (3): 138-147.doi: 10.12133/j.smartag.SA202402002

• 信息处理与决策 • 上一篇    下一篇

基于改进YOLACT的油茶叶片炭疽病感染严重程度分级模型

聂刚刚1,2, 饶洪辉1,2(), 李泽锋1,2, 刘木华1,2   

  1. 1. 江西农业大学 工学院,江西 南昌 330045,中国
    2. 江西省现代农业装备重点实验室,江西 南昌 330045,中国
  • 收稿日期:2024-02-02 出版日期:2024-05-30
  • 基金资助:
    江西省科技计划项目(20141BBF60057); 江西省林业厅油茶研究专项(YCYJZX2023221)
  • 作者简介:
    聂刚刚,研究方向为机器视觉。E-mail:
  • 通信作者:
    饶洪辉,博士,教授,研究方向为现代农业装备、机器视觉。E-mail:

Severity Grading Model for Camellia Oleifera Anthracnose Infection Based on Improved YOLACT

NIE Ganggang1,2, RAO Honghui1,2(), LI Zefeng1,2, LIU Muhua1,2   

  1. 1. College of Engineering, Jiangxi Agriculture University, Nanchang 330045, China
    2. Jiangxi Key Laboratory of Modern Agricultural Equipment, Jiangxi Agriculture University, Nanchang 330045, China
  • Received:2024-02-02 Online:2024-05-30
  • corresponding author:
    RAO Honghui, E-mail:
  • About author:
    NIE Ganggang, E-mail:
  • Supported by:
    Jiangxi Science and Technology Planning Project(20141BBF60057); Provincial Forestry Bureau Camellia Fruit Research Special Project(YCYJZX2023221)

摘要:

[目的/意义] 炭疽病(anthracnose)作为油茶生长过程中重要的病害,其严重程度的精准判定对于精准施药和科学管理具有重大意义。本研究提出了一种改进YOLACT(You Only Look At CoefficienTs)分级模型Camellia-YOLACT,旨在实现对油茶叶片炭疽病感染严重程度的自动、高效判定。 [方法] 首先在YOLACT主干网络部分使用Swin-Transformer来进行特征提取。Transformer架构的自注意力机制拥有全局感受野及移位窗口等特性,有效地增强了模型的特征提取能力;引入加权双向特征金字塔网络,融合不同尺度的特征信息,加强模型对不同尺度目标的检测能力,提高模型的检测精度;在激活函数的选择上,采用非线性能力更强的HardSwish激活函数替换原模型的ReLu激活函数。由于HardSwish在负值区域不是完全截断,对于输入数据中的噪声具有更高的鲁棒性,自然环境下的图像有着复杂的背景和前景信息,HardSwish的鲁棒性有助于模型更好地处理这些情况,进一步提升精度。 [结果和讨论] 采用迁移学习方式在油茶炭疽病感染严重程度分级数据集上进行实验验证。消融实验结果表明,本研究提出的Camellia-YOLACT模型的mAP75为86.8%,较改进前提升5.7%;mAPall为78.3%,较改进前提升2.5%;mAR为91.6%,较改进前提升7.9%。对比实验结果表明,Camellia-YOLACT在精度和速度方面表现均好于SOLO(Segmenting Objects by Locations),与Mask R-CNN算法相比,其检测速度提升了2倍。在室外的36组分级实验中进一步验证了Camellia-YOLACT模型的性能,其对油茶炭疽病严重程度的分级正确率达到了94.4%,K值平均绝对误差为1.09%。 [结论] 本研究提出的Camellia-YOLACT模型在油茶叶片和炭疽病病斑分割上具有较高的精度,能够实现对油茶炭疽病严重程度的自动分级,为油茶病害的精准防治提供技术支持,进一步推动油茶炭疽病诊断的自动化和智能化。

关键词: 油茶, 叶部病害, 炭疽病, BiFPN, YOLACT, Transformer, 深度学习

Abstract:

[Objective] Camellia oleifera is one of the four major woody oil plants in the world. Diseases is a significant factor leading to the decline in quality of Camellia oleifera and the financial loss of farmers. Among these diseases, anthracnose is a common and severe disease in Camellia oleifera forests, directly impacting yields and production rates. Accurate disease assessment can improve the prevention and control efficiency and safeguarding the farmers' profit. In this study, an improved You Only Look at CoefficienTs (YOLACT) based method was proposed to realize automatic and efficient grading of the severity of Camellia oleifera leaf anthracnose. [Methods] High-resolution images of Camellia oleifera anthracnose leaves were collected using a smartphone at the National Camellia oleifera Seed Base of Jiangxi Academy of Forestry, and finally 975 valid images were retained after a rigorous screening process. Five data enhancement means were applied, and a data set of 5 850 images was constructed finally, which was divided into training, validation, and test sets in a ratio of 7:2:1. For model selection, the Camellia-YOLACT model was proposed based on the YOLACT instance segmentation model, and by introducing improvements such as Swin-Transformer, weighted bi-directional feature pyramid network, and HardSwish activation function. The Swin Transformer was utilized for feature extraction in the backbone network part of YOLACT, leveraging the global receptive field and shift window properties of the self-attention mechanism in the Transformer architecture to enhance feature extraction capabilities. Additionally, a weighted bidirectional feature pyramid network was introduced to fuse feature information from different scales to improve the detection ability of the model for objects at different scales, thereby improving the detection accuracy. Furthermore, to increase the the model's robustness against the noise in the input data, the HardSwish activation function with stronger nonlinear capability was adopted to replace the ReLu activation function of the original model. Since images in natural environments usually have complex background and foreground information, the robustness of HardSwish helped the model better handling these situations and further improving the detection accuracy. With the above improvements, the Camellia-YOLACT model was constructed and experimentally validated by testing the Camellia oleifera anthracnose leaf image dataset. [Results and Discussions] A transfer learning approach was used for experimental validation on the Camellia oleifera anthracnose severity grading dataset, and the results of the ablation experiments showed that the mAP75 of Camellia-YOLACT proposed in this study was 86.8%, mAPall was 78.3%, mAR was 91.6% which were 5.7%, 2.5% and 7.9% higher than YOLACT model. In the comparison experiments, Camellia-YOLACT performed better than Segmenting Objects by Locations (SOLO) in terms of both accuracy and speed, and its detection speed was doubled compared to Mask R-CNN algorithm. Therefore, the Camellia-YOLACT algorithm was suitable in Camellia oleifera gardens for anthracnose real-time segmentation. In order to verify the outdoors detection performance of Camellia-YOLACT model, 36 groups of Camellia oleifera anthracnose grading experiments were conducted. Experimental results showed that the grading correctness of Camellia oleifera anthracnose injection severity reached 94.4%, and the average absolute error of K-value was 1.09%. Therefore, the Camellia-YOLACT model proposed in this study has a better performance on the grading of the severity of Camellia oleifera anthracnose. [Conclusions] The Camellia-YOLACT model proposed got high accuracy in leaf and anthracnose segmentation of Camellia oleifera, on the basis of which it can realize automatic grading of the severity of Camellia oleifera anthracnose. This research could provide technical support for the precise control of Camellia oleifera diseases.

Key words: Camellia oleifera, leaf disease, anthracnose, BiFPN, YOLACT, Transformer, deep learning