Abstract:Aiming to address the issues of low efficiency and poor consistency in manual grading of potted ornamental plants such as Ananas comosus var. bracteatus (‘White Snow Pineapple’), an intelligent grading method was proposed based on a lightweight segmentation model and multi-dimensional phenotypic feature extraction, and a corresponding automated grading equipment was developed. To enhance the real-time performance and accuracy of plant segmentation, the YOLO v8n-seg model was structurally optimized by introducing the lightweight reparameterized cross stage partial ( REPCSP) module to replace the original CSP bottleneck with 2 convolutions (C2f) module and adopting shared convolutional segmentation head (SCSHead) in place of the conventional segmentation head, resulting in the YOLO v8n-RS model. The improved model achieved a segmentation accuracy (mAP) of 98. 0%, with an inference speed of 1 121. 8 f/ s, and only 1. 7 ×106 parameters. Compared with YOLO v8n-seg, the inference speed was increased by 30. 8%, making it more suitable for real-time grading scenarios. To meet the requirements of intelligent grading for Snow Pineapple, key phenotypic traits, including plant height, flower diameter, inclination angle, and flower fullness were accurately extracted by combining the segmentation results with depth image processing techniques. Experimental results showed that the mean absolute errors for plant height, flower diameter and inclination angle were 0. 745 cm, 0. 410 cm and 1. 627°, respectively, with corresponding R2 values of 0. 933, 0. 915 and 0. 773. The flower fullness classification achieved an accuracy of 85. 3% and an F1-score of 84. 9%. Based on the proposed method and system, an automated grading device was developed, and a field test involving 100 Snow Pineapple plants was conducted. The system achieved a grading accuracy of 89. 0%, with an average processing time of 3. 54 s per plant, demonstrating its high efficiency and stability in real-world production environments.