Dual-Phase Severity Grading of Strawberry Angular Leaf Spot Based on Improved YOLOv11 and OpenCV

<i>Phyllosticta fragaricola</i>-induced angular leaf spot causes substantial economic losses in global strawberry production, necessitating advanced severity assessment methods. This study proposed a dual-phase grading framework integrating deep learning and computer vision. The enhanced...

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Main Authors: Yi-Xiao Xu, Xin-Hao Yu, Qing Yi, Qi-Yuan Zhang, Wen-Hao Su
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Plants
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Online Access:https://www.mdpi.com/2223-7747/14/11/1656
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author Yi-Xiao Xu
Xin-Hao Yu
Qing Yi
Qi-Yuan Zhang
Wen-Hao Su
author_facet Yi-Xiao Xu
Xin-Hao Yu
Qing Yi
Qi-Yuan Zhang
Wen-Hao Su
author_sort Yi-Xiao Xu
collection DOAJ
description <i>Phyllosticta fragaricola</i>-induced angular leaf spot causes substantial economic losses in global strawberry production, necessitating advanced severity assessment methods. This study proposed a dual-phase grading framework integrating deep learning and computer vision. The enhanced You Only Look Once version 11 (YOLOv11) architecture incorporated a Content-Aware ReAssembly of FEatures (CARAFE) module for improved feature upsampling and a squeeze-and-excitation (SE) attention mechanism for channel-wise feature recalibration, resulting in the YOLOv11-CARAFE-SE for the severity assessment of strawberry angular leaf spot. Furthermore, an OpenCV-based threshold segmentation algorithm based on H-channel thresholds in the HSV color space achieved accurate lesion segmentation. A disease severity grading standard for strawberry angular leaf spot was established based on the ratio of lesion area to leaf area. In addition, specialized software for the assessment of disease severity was developed based on the improved YOLOv11-CARAFE-SE model and OpenCV-based algorithms. Experimental results show that compared with the baseline YOLOv11, the performance is significantly improved: the box mAP@0.5 is increased by 1.4% to 93.2%, the mask mAP@0.5 is increased by 0.9% to 93.0%, the inference time is shortened by 0.4 ms to 0.9 ms, and the computational load is reduced by 1.94% to 10.1 GFLOPS. In addition, this two-stage grading framework achieves an average accuracy of 94.2% in detecting selected strawberry horn leaf spot disease samples, providing real-time field diagnostics and a high-throughput phenotypic analysis for resistance breeding programs. This work demonstrates the feasibility of rapidly estimating the severity of strawberry horn leaf spot, which will establish a robust technical framework for strawberry disease management under field conditions.
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series Plants
spelling doaj-art-d18b84762e084f1da3f392f45cc84b6a2025-08-20T03:11:19ZengMDPI AGPlants2223-77472025-05-011411165610.3390/plants14111656Dual-Phase Severity Grading of Strawberry Angular Leaf Spot Based on Improved YOLOv11 and OpenCVYi-Xiao Xu0Xin-Hao Yu1Qing Yi2Qi-Yuan Zhang3Wen-Hao Su4College of Engineering, China Agricultural University, 17 Qinghua East Road, Haidian District, Beijing 100083, ChinaCollege of Engineering, China Agricultural University, 17 Qinghua East Road, Haidian District, Beijing 100083, ChinaCollege of Engineering, China Agricultural University, 17 Qinghua East Road, Haidian District, Beijing 100083, ChinaCollege of Engineering, China Agricultural University, 17 Qinghua East Road, Haidian District, Beijing 100083, ChinaCollege of Engineering, China Agricultural University, 17 Qinghua East Road, Haidian District, Beijing 100083, China<i>Phyllosticta fragaricola</i>-induced angular leaf spot causes substantial economic losses in global strawberry production, necessitating advanced severity assessment methods. This study proposed a dual-phase grading framework integrating deep learning and computer vision. The enhanced You Only Look Once version 11 (YOLOv11) architecture incorporated a Content-Aware ReAssembly of FEatures (CARAFE) module for improved feature upsampling and a squeeze-and-excitation (SE) attention mechanism for channel-wise feature recalibration, resulting in the YOLOv11-CARAFE-SE for the severity assessment of strawberry angular leaf spot. Furthermore, an OpenCV-based threshold segmentation algorithm based on H-channel thresholds in the HSV color space achieved accurate lesion segmentation. A disease severity grading standard for strawberry angular leaf spot was established based on the ratio of lesion area to leaf area. In addition, specialized software for the assessment of disease severity was developed based on the improved YOLOv11-CARAFE-SE model and OpenCV-based algorithms. Experimental results show that compared with the baseline YOLOv11, the performance is significantly improved: the box mAP@0.5 is increased by 1.4% to 93.2%, the mask mAP@0.5 is increased by 0.9% to 93.0%, the inference time is shortened by 0.4 ms to 0.9 ms, and the computational load is reduced by 1.94% to 10.1 GFLOPS. In addition, this two-stage grading framework achieves an average accuracy of 94.2% in detecting selected strawberry horn leaf spot disease samples, providing real-time field diagnostics and a high-throughput phenotypic analysis for resistance breeding programs. This work demonstrates the feasibility of rapidly estimating the severity of strawberry horn leaf spot, which will establish a robust technical framework for strawberry disease management under field conditions.https://www.mdpi.com/2223-7747/14/11/1656deep learningstrawberry angular leafspot diseasecomputer visionseverity classificationsmart agriculture
spellingShingle Yi-Xiao Xu
Xin-Hao Yu
Qing Yi
Qi-Yuan Zhang
Wen-Hao Su
Dual-Phase Severity Grading of Strawberry Angular Leaf Spot Based on Improved YOLOv11 and OpenCV
Plants
deep learning
strawberry angular leafspot disease
computer vision
severity classification
smart agriculture
title Dual-Phase Severity Grading of Strawberry Angular Leaf Spot Based on Improved YOLOv11 and OpenCV
title_full Dual-Phase Severity Grading of Strawberry Angular Leaf Spot Based on Improved YOLOv11 and OpenCV
title_fullStr Dual-Phase Severity Grading of Strawberry Angular Leaf Spot Based on Improved YOLOv11 and OpenCV
title_full_unstemmed Dual-Phase Severity Grading of Strawberry Angular Leaf Spot Based on Improved YOLOv11 and OpenCV
title_short Dual-Phase Severity Grading of Strawberry Angular Leaf Spot Based on Improved YOLOv11 and OpenCV
title_sort dual phase severity grading of strawberry angular leaf spot based on improved yolov11 and opencv
topic deep learning
strawberry angular leafspot disease
computer vision
severity classification
smart agriculture
url https://www.mdpi.com/2223-7747/14/11/1656
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