A Resource-Efficient Hybrid CNN-LSTM network for image-based bean leaf disease classification

arXiv cs.CV / 4/16/2026

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Key Points

  • The paper introduces a lightweight hybrid CNN–LSTM architecture for bean leaf disease image classification aimed at improving diagnostic accuracy while reducing memory requirements for deployment on portable devices.
  • It reports 94.38% classification accuracy with a very small model footprint of 1.86 MB, representing about a 70% size reduction versus conventional CNN-based systems.
  • The authors evaluate image augmentation strategies and find that tailored augmentation transformations better preserve diagnostic patterns than generic augmentation combinations.
  • Experiments on the iBean dataset show state-of-the-art performance, including an F1 score of 99.22% with an EfficientNet-B7+LSTM variant, supporting real-time agricultural decision support in resource-constrained settings.
  • The study provides publicly available code and augmented datasets via a GitHub repository to facilitate reuse and further research.

Abstract

Accurate and resource-efficient automated diagnosis is a cornerstone of modern agricultural expert systems. While Convolutional Neural Networks (CNNs) have established benchmarks in plant pathology, their ability to capture long-range spatial dependencies is often limited by standard pooling layers, and their high memory footprint hinders deployment on portable devices. This paper proposes a lightweight hybrid CNN-LSTM system for bean leaf disease classification. By integrating an LSTM layer to model the spatial-sequential relationships within feature maps, our hybrid architecture achieves a 94.38% accuracy while maintaining an exceptionally small footprint of 1.86 MB; a 70% reduction in size compared to traditional CNN-based systems. Furthermore, we provide a systematic evaluation of image augmentation strategies, demonstrating that tailored transformations are superior to generic combinations for maintaining the integrity of diagnostic patterns. Results on the \textit{ibean} dataset confirm that the proposed system achieves state-of-the-art F1 scores of 99.22% with EfficientNet-B7+LSTM, providing a robust and scalable framework for real-time agricultural decision support in resource-constrained environments. The code and augmented datasets used in this study are publicly available on this \href{https://github.com/HJin-R/bean_disease}{Github} repo.