Abstract:Sandalwood seedlings rely on companion plants during their growth, which are often interplanted with other crops, resulting in a complex growth environment that makes accurate detection challenging, thereby affecting the effective assessment of sandalwood productivity. To address this issue, a lightweight detection algorithm, (YOLO v8n improved for sandalwood plant seedlings detection,YOLO?SPS), was proposed based on multispectral image fusion and an improved YOLO v8n. The SwinFusion model was utilized to fuse near?infrared and visible light remote sensing images of sandalwood seedlings, enhancing their texture and color features. The cross stage partial network fusion_spatial and channel reconstruction convolution module, which combined spatial and channel reconstruction, was introduced into the backbone network of the YOLO v8n model to improve feature extraction capabilities. The partial self?attention (PSA) mechanism was incorporated into the neck network to optimize global perception and reduce computational costs. Finally, Shape?IoU was adopted as the bounding box loss function to further enhance detection accuracy. Experimental results demonstrated that the YOLO?SPS model achieved precision, recall, and mean average precision of 92.8%, 93.2%, and 95.9%, respectively, significantly outperforming the original YOLO v8n model and surpassing five mainstream detection models, including YOLO v5s, YOLO v6n, YOLO v7?tiny, YOLO v9?t, and YOLO v10n. The research result can provide effective technical support for the precise monitoring of sandalwood seedlings during their early growth stages.