With the growing demand of industrial automation, 3D point cloud anomaly detection has played an increasingly important role in product quality control. However, the existing methods often rely on a single feature, leading to information loss and accuracy reduction. To address these issues, an unsupervised point cloud anomaly detection method based on multi-representation fusion was proposed, called MRF (Multi-Representation Fusion). MRF used multi-angle rotation and various coloring schemes to render point clouds into multi-modal images, and employed pre-trained 2D convolutional neural networks to extract rich semantic features. Simultaneously, pre-trained Point Transformer was adopted to extract 3D structural features. After the above, by fusing 2D image semantic features and 3D structural features, MRF was able to capture point cloud information more comprehensively. In the anomaly detection stage, abnormal point clouds were identified effectively by using a method based on positive sample memory banks and nearest neighbor search. Experimental results on MVTec 3D AD dataset show that MRF achieves a point cloud-level AUROC (Area Under the Receiver Operating Characteristic curve) of 0.972 and a point-level AUPRO (Area Under the Per-Region Overlap) of 0.948, significantly outperforming existing methods. It can be seen that the effectiveness and robustness of MRF makes it a highly promising solution for industrial applications.
When multiple feature modalities are fused, there is a superposition of noise, and the cascaded structure used to reduce the differences between modalities does not fully utilize the feature information between modalities. To address these issues, a cross-modal Dual-stream Alternating Interactive Network (DAINet) method was proposed. Firstly, a Dual-stream Alternating Enhancement (DAE) module was constructed to fuse modal features in interactive dual-branch way. And by learning mapping relationships between modalities and employing bidirectional feedback adjustments of InFrared-VISible-InFrared (IR-VIS-IR) and VISible-InfRared-VISible (VIS-IR-VIS), the cross suppression of inter-modal noise was realized. Secondly, a Cross-Modal Feature Interaction (CMFI) module was constructed, and the residual structure was introduced to integrate low-level and high-level features within and between infrared-visible modalities, thereby minimizing differences and maximizing inter-modal feature utilization. Finally, on a self-constructed infrared-visible multi-modal typhoon dataset and a publicly available RGB-NIR multi-modal dataset, the effectiveness of DAE module and CMFI module was verified. Experimental results demonstrate that compared to the simple cascading fusion method on the self-constructed typhoon dataset, the proposed DAINet-based feature fusion method improves the overall classification accuracy by 6.61 and 3.93 percentage points for the infrared and visible modalities, respectively, with G-mean values increased by 6.24 and 2.48 percentage points, respectively. These results highlight the generalizability of the proposed method for class-imbalanced classification tasks. On the RGB-NIR dataset, the proposed method achieves the overall classification accuracy improvements of 13.47 and 13.90 percentage points, respectively, for the two test modalities. At the same time, experimental results of comparing with IFCNN (general Image Fusion framework based on Convolutional Neural Network) and DenseFuse methods demonstrate that the proposed method improves the overall classification accuracy by 9.82, 6.02, and 17.38, 1.68 percentage points for the two test modalities on the self-constructed typhoon dataset.
The trend of green logistics pushes the use of electric vehicles into cold chain logistics. Concerning the problem that maintaining a low temperature environment requires a lot of energy in electric vehicle cold chain distribution, as well as the phenomena that the limited driving range and long charging time of electric vehicles make high operation cost, the Refrigerated Electric Vehicle Routing Problem (REVRP) in electric vehicle distribution was thought deeply. Considering the characteristics of electric vehicle energy consumption and the charging requirements of social recharging stations, a linear programming model was developed with the objective of minizing total distribution cost, and the objective function was composed of fixed cost and variable cost, in the variable cost, transportation cost and cooling cost were included. The capacity constraints and power constraints were considered in the model, and a Hybrid Ant Colony Optimization (HACO) algorithm was designed to solve this model. Especially, more attention was paid to designing transfer rules suitable for social recharging stations and four local optimization operators. Based on improving the Solomon benchmark examples, the small-scale and large-scale example sets were formed, and the performance of ACO algorithm and the optimization operators were through experiments. The experiment results show that ACO algorithm and CPLEX (WebSphere ILOG CPLEX) solver can find the exact solution in the small-scale example set, and ACO algorithm can save the operation time by 99.6% . In the large-scale example set, compared with ACO algorithm, HACO algorithm combing the four optimization operators has the average optimization efficiency increased by 4.45%. The proposed algorithm can obtain a feasible solution for REVRP in a limited time.