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Perceiving grape harvest scene to locate picking point using 3D point clouds
Transactions of the Chinese Society of Agricultural Engineering 2026, 42(2): 195-204
Published: 30 January 2026
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Accurate recognition of the grape picking point is essential for the intelligent, efficient, and non-destructive harvesting in grape-picking robots. However, the robustness of the 3D localization is often confined to the various influencing factors, such as the occlusions, irregular lighting, and the complex spatial distribution of the grape clusters under unstructured orchard environments. Therefore, it is highly required to enhance the overall reliability of the harvesting decisions. In this study, a dual-modal visual perception and cognition framework was proposed to integrate both 3D point clouds and 2D RGB images for the robust and precise picking point localization under diverse orchard conditions. Firstly, the 3D semantic scene was selected. Point Transformer V2 (PTV2), a point-cloud processing model was incorporated the grouped vector attention and relative positional encoding, in order to capture both local geometric structures and long-range contextual dependencies. Point clouds were acquired from a depth camera, and then semantically segmented into the classes, such as the grapes, stems, and branches. The structural foundation was formed for the subsequent geometric analysis. The PTV2 model was achieved in the high accuracy of the segmentation, with a mean Intersection over Union (mIoU) of 89.83%, and the IoU values for the peduncle and branche were 78.55% and 84.20% respectively. The strong recognition was realized in the real orchard scenarios. A 3D grape picking point localization algorithm (3D GPPLA) was proposed to determine the picking points within the complex arrangements of the grape cluster. A two-stage clustering was introduced using DBSCAN and K-Means. Multi-cluster grapes were semantically segmented into the independent candidate cluster point clouds. After that, the morphology validation was implemented to determine whether each cluster was corresponded to an individual grape bunch. The recursive depth was also restricted to prevent the over-segmentation for the computational efficiency. Once the invalid partition was obtained within the allowed depth, the system was rolled back into a previous clustering state for the stability. Once a single grape bunch was identified, 3D GPPLA was used to estimate the picking point, according to the spatial relationship between the grape centroid and the peduncle region. Specifically, the minimum bounding box around the grape-peduncle subset was computed to determine the optimal picking direction. The peduncle proximity and accessibility were evaluated for the minimal damage during separation, and the consistent harvesting performance. A 2D fallback strategy was also introduced to further enhance the robustness, in cases where the 3D approach failed, due to the severe occlusion, missing depth data, or segmentation noise. Once one failure was detected, the 2D RGB image was extracted to switch into the image inference. By leveraging SegFormer, a state-of-the-art transformer-based semantic segmentation network, two-dimensional images are partitioned into high-fidelity semantic representations, including grape and peduncle, among others. The 2D GPPLA algorithm was then computed the picking points in the image space, according to the shape heuristics and spatial priors. Subsequently, the 3D point cloud was projected after depth-aligned pixel mapping. The fallback mechanism was enhanced the resilience in the cluttered and partially observable environments. While the richer texture and color cues available in RGB images were also compensated for the limitations in the point-cloud resolution and sensor noise. A custom dataset was comprised 1 847 grape clusters that collected under natural orchard conditions. The 3D GPPLA was achieved in a picking-point localization success rate of 89.11%. Particularly, there were the success rates of 98.81% in the single-cluster scenarios and 80.95% in the multi-cluster arrangements, highlighting its adaptability to the varying levels of the structural complexity. When combined with the 2D fallback strategy, the high overall reliability was significantly reduced the failure cases under the cluttered and occluded scenarios. As such, the framework was integrated with the advanced 3D semantic segmentation, adaptive multi-stage clustering, and cross-modal compensation. The accurate, stable, and efficient picking-point localization was achieved in the unstructured vineyard environments. This finding can also provide a solid technical contribution to the practical deployment of the grape-harvesting robots in smart agriculture.

Open Access Article Issue
An Optimized Unsupervised Defect Detection Approach via Federated Learning and Adaptive Embeddings Knowledge Distillation
Computers, Materials & Continua 2025, 84(1): 1839-1861
Published: 09 June 2025
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Downloads:44

Defect detection based on computer vision is a critical component in ensuring the quality of industrial products. However, existing detection methods encounter several challenges in practical applications, including the scarcity of labeled samples, limited adaptability of pre-trained models, and the data heterogeneity in distributed environments. To address these issues, this research proposes an unsupervised defect detection method, FLAME (Federated Learning with Adaptive Multi-Model Embeddings). The method comprises three stages: (1) Feature learning stage: this work proposes FADE (Feature-Adaptive Domain-Specific Embeddings), a framework employs Gaussian noise injection to simulate defective patterns and implements a feature discriminator for defect detection, thereby enhancing the pre-trained model’s industrial imagery representation capabilities. (2) Knowledge distillation co-training stage: a multi-model feature knowledge distillation mechanism is introduced. Through feature-level knowledge transfer between the global model and historical local models, the current local model is guided to learn better feature representations from the global model. The approach prevents local models from converging to local optima and mitigates performance degradation caused by data heterogeneity. (3) Model parameter aggregation stage: participating clients utilize weighted averaging aggregation to synthesize an updated global model, facilitating efficient knowledge consolidation. Experimental results demonstrate that FADE improves the average image-level Area under the Receiver Operating Characteristic Curve (AUROC) by 7.34% compared to methods directly utilizing pre-trained models. In federated learning environments, FLAME’s multi-model feature knowledge distillation mechanism outperforms the classic FedAvg algorithm by 2.34% in average image-level AUROC, while exhibiting superior convergence properties.

Issue
Orchard-Wide Visual Perception and Autonomous Operation of Fruit Picking Robots: A Review
Smart Agriculture 2024, 6(5): 20-39
Published: 30 September 2024
Abstract PDF (1.3 MB) Collect
Downloads:161
Significance

Fruit-picking robot stands as a crucial solution for achieving intelligent fruit harvesting. Significant progress has been made in developing foundational methods for picking robots, such as fruit recognition, orchard navigation, path planning for picking, and robotic arm control, the practical implementation of a seamless picking system that integrates sensing, movement, and picking capabilities still encounters substantial technical hurdles. In contrast to current picking systems, the next generation of fruit-picking robots aims to replicate the autonomous skills exhibited by human fruit pickers. This involves effectively performing ongoing tasks of perception, movement, and picking without human intervention. To tackle this challenge, this review delves into the latest research methodologies and real-world applications in this field, critically assesses the strengths and limitations of existing methods and categorizes the essential components of continuous operation into three sub-modules: local target recognition, global mapping, and operation planning.

Progress

Initially, the review explores methods for recognizing nearby fruit and obstacle targets. These methods encompass four main approaches: low-level feature fusion, high-level feature learning, RGB-D information fusion, and multi-view information fusion, respectively. Each of these approaches incorporates advanced algorithms and sensor technologies for cluttered orchard environments.For example, low-level feature fusion utilizes basic attributes such as color, shapes and texture to distinguish fruits from backgrounds, while high-level feature learning employs more complex models like convolutional neural networks to interpret the contextual relationships within the data. RGB-D information fusion brings depth perception into the mix, allowing robots to gauge the distance to each fruit accurately. Multi-view information fusion tackles the issue of occlusions by combining data from multiple cameras and sensors around the robot, providing a more comprehensive view of the environment and enabling more reliable sensing. Subsequently, the review shifts focus to orchard mapping and scene comprehension on a broader scale. It points out that current mapping methods, while effective, still struggle with dynamic changes in the orchard, such as variations of fruits and light conditions. Improved adaptation techniques, possibly through machine learning models that can learn and adjust to different environmental conditions, are suggested as a way forward. Building upon the foundation of local and global perception, the review investigates strategies for planning and controlling autonomous behaviors. This includes not only the latest advancements in devising movement paths for robot mobility but also adaptive strategies that allow robots to react to unexpected obstacles or changes within the whole environment. Enhanced strategies for effective fruit picking using the Eye-in-Hand system involve the development of more dexterous robotic hands and improved algorithms for precisely predicting the optimal picking point of each fruit. The review also identifies a crucial need for further advancements in the dynamic behavior and autonomy of these technologies, emphasizing the importance of continuous learning and adaptive control systems to improve operational efficiency in diverse orchard environments.

Conclusions and Prospects

The review underscores the critical importance of coordinating perception, movement, and picking modules to facilitate the transition from a basic functional prototype to a practical machine. Moreover, it emphasizes the necessity of enhancing the robustness and stability of core algorithms governing perception, planning, and control, while ensuring their seamless coordination which is a central challenge that emerges. Additionally, the review raises unresolved questions regarding the application of picking robots and outlines future trends, include deeper integration of stereo vision and deep learning, enhanced global vision sampling, and the establishment of standardized evaluation criteria for overall operational performance. The paper can provide references for the eventual development of robust, autonomous, and commercially viable picking robots in the future.

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