Abstract:The detection and identification of rice leaf diseases hold significant importance in agricultural production. To address the challenges of diverse and complex field environments, difficulties in detecting small disease targets, and deployment constraints of intelligent devices for rice leaf disease detection, a lightweight object detection model named YOLO v8-PicoDet was proposed, which integrated the advantages of YOLO v8n and PicoDet, aiming to achieve efficient detection of rice leaf diseases. Firstly, the model took efficient symmetric network (ESNet) as its backbone and introduced the simple attention module (SimAM) to reduce the number of model parameters and the computational cost. As a result, the number of parameters was reduced by 1.6×10^6 and the FLOPs was decreased by 2.1×10^9. Secondly, the cross stage partial path aggregation network (CSP-PAN) feature fusion was constructed, which enhanced the detection ability for small target lesions. Again, the convolutional block attention module (CBAM) was introduced into the detection head, enhancing the model's ability to represent the characteristics of complex lesions. Finally, the GIoU Loss and Distribution Focal Loss functions were combined and optimized to optimize the model detection and classification performance from multiple dimensions such as classification, regression and confidence. The experiment was conducted based on the Raspberry Pi 4B platform, and the results showed that the optimized model can achieve an inference speed of 28.5 f/s, overcoming the deficiency that many models were difficult to run on portable devices. Meanwhile, the model achieved 93.8% mAP@0.5 and 76.9% mAP@0.5:0.95, which was 0.9 percentage points and 1.3 percentage points higher than that of the original YOLO v8n model, and its performance was superior to existing mainstream detection models.