Abstract:Aiming to address the issue of insufficient detection accuracy for wheat heads in complex field environments caused by plant occlusion and growth stage variations, a detection algorithm named GB YOLO v5su, was proposed which integrated lightweight design with multi-scale feature enhancement. Building upon the YOLO v5su model, the algorithm reconstructed the backbone network by incorporating Ghost modules to form a lightweight GhostNet structure, substantially reducing computational complexity and model parameters while maintaining representational capacity. The original PANet was replaced with a weighted bidirectional feature pyramid network (BiFPN), which enhanced multi-scale feature representation through efficient cross-scale connections and a learnable adaptive weighting mechanism. Subsequently, a P2 detection layer was introduced to construct a four-scale feature pyramid, effectively leveraging high-resolution shallow features to improve detection sensitivity for small-scale wheat heads. Furthermore, the MPDIoU loss function was adopted to replace CIoU, which optimized bounding box regression by directly minimizing the corner point distance, thereby improving localization accuracy. Experimental results on the public GWHD2021 dataset demonstrated that the proposed algorithm reduced the model parameter count to 5.38×10? while achieving an average precision (AP50) of 92.8%, striking an effective balance between accuracy and efficiency. Extensive ablation studies and cross-dataset tests further validated the contribution of each module and confirmed the strong robustness of the algorithm. The research result can provide an efficient, practical, and lightweight deployment solution for achieving realtime and accurate wheat head detection in resource-constrained field edge computing scenarios.