Lightweight fresh tea leaf recognition method based on improved YOLOv5s

The classification and recognition of tea buds represents a crucial aspect of renowned tea production. In view of the problems of large model size，large computational complexity and inability to distinguish the picking morphology of the current tea bud recognition algorithm，this study proposes an enhanced fresh tea leaf recognition model（YOLOv5s-SPCS）based on YOLOv5s as the foundational model. Firstly，images of fresh tea leaves were collected in both laboratory and natural environments to create a dataset of fresh tea leaves. This was done through offline and online collection of images in multiple scenarios，with the resulting images divided into a training set and a test set. Secondly，the Shuffle Block module was constructed based on the ShuffleNetV2 idea for replacing the convolution module in YOLOv5s backbone network，which reduced the number of model parameters and the amount of computation while increasing the speed of feature extraction. Subsequently，the Partial Convolution structure，PConv and SimAM were incorporated into the neck network to construct the C3-PCS module，replacing the original C3 structure which further reduced the model computational redundancy and memory access，while improving the recognition accuracy with a minimal increase in the number of parameters. Finally，the SIoU bounding box loss function was employed to enhance the convergence velocity and precision of the prediction frame. In addition to accelerating the convergence of the model prediction frame regression，the use of this loss function also generates more accurately positioned prediction frames. The experimental results demonstrate that the enhanced YOLOv5s-SPCS model exhibits 14%，14% and 16% of the YOLOv5s model in terms of the number of parameters，computational volume and weight file. The size of the model is，respectively，with an accuracy of 81.8% and a mean average precision（mAP）of 82.4% for the fresh tea image recognition，which is 2.7% more accurate than the original model. The accuracy was enhanced by 2.7 percentage points，while the mean average precision of mAP remained unaltered. Furthermore，the overall performance of the enhanced YOLOv5s-SPCS model is superior to that of the prevailing target detection models，including Faster R-CNN，SSD，YOLOv3，and YOLOv4. This study offers a valuable technical foundation for fresh tea leaves recognition classification and subsequent mobile deployment.