Smart manufacturing has been transforming toward industrial digitalization integrated with various advanced technologies. Metaverse has been evolving as a next-generation paradigm of a digital space extended and augmented by reality. In the metaverse, users are interconnected for various virtual activities. In consideration of advanced possibilities that may be brought by the metaverse, it is envisioned that industrial metaverse should be integrated into smart manufacturing to upgrade industry for more visible, intelligent and efficient production in the future. Therefore, a conceptual model, named IMverse Model, and novel characteristics of the industrial metaverse for smart manufacturing are proposed in this article. Besides, an industrial metaverse architecture, named IMverse Architecture, is proposed involving several key enabling technologies. Typical innovative applications of the industrial metaverse throughout the whole product life cycle for smart manufacturing are presented with insights. Nonetheless, in prospect of future, the industrial metaverse still faces limitations and is far from implementation. Thus, challenges and open issues of the industrial metaverse for smart manufacturing are discussed, then outlook is provided for further research and application.

Micro-expression (ME) is an instinctive reaction that is not controlled by thoughts. It reveals one's inner feelings, which is significant in sentiment analysis and lie detection. Since micro-expression is expressed as subtle facial changes within particular facial action units, learning discriminative and generalized features for Micro-expression Recognition (MER) is challenging. To achieve the purpose, this paper proposes a novel MER framework that simultaneously integrates supervised Prototype-based Memory Contrastive Learning (PMCL) for discriminative feature mining and adds Self-expression Reconstruction (SER) as an auxiliary task and regularization for better generalization. In particular, the proposed SER module is forced as a regularization by reconstructing input ME from the randomly dropped patch- wise features in the bottleneck. And, the PMCL module globally compares historical and current cluster agents learned from training instances to enhance intra-class compactness and inter-class separability. Extensive experiments are conducted on three benchmarks, e.g., SMIC, CASME II, and SAMM, under evaluation criteria of both Composite Database Evaluation (CDE) and Single Database Evaluation (SDE) protocols. The results show our method surpasses other state-of-the-art approaches under various evaluation metrics, achieving overall 86.30% unweighed F1-score and 88.30% unweighed average recall on the composite dataset. Furthermore, the ablation studies verify the effectiveness of our SER for better generalization and PMCL for better discrimination in learning feature representation from limited micro-expression samples.

Since the discovery of the giant magnetoresistive (GMR) effect, GMR sensors have gained much attention in last decades due to their high sensitivity, small size, and low cost. The full Wheatstone-bridge-based GMR sensor is most useful in terms of the application point of view. However, its manufacturing process is usually complex. In this paper, we present an efficient and concise approach to fabricate a full Wheatstone-bridge-based angular GMR sensor by depositing one GMR film stack, utilizing simple patterned processes, and a concise post-annealing procedure based on a special layout. The angular GMR sensor is of good linear performance and achieves a sensitivity of 0.112 mV/V/Oe at the annealing temperature of 260 °C in the magnetic field range from −50 to +50 Oe. This work provides a design and method for GMR-sensor manufacturing that is easy for implementation and suitable for mass production.

Augmented reality (AR) applications are increasingly being used in various fields (e.g., design, maintenance, assembly, repair, training, etc.), as AR techniques help improve efficiency and reduce costs. Moreover, collaborative AR systems extend applicability, allowing for collaborative environments for different roles. In this paper, we propose a multi-user collaborative AR system (aptly called the “multi-user collaborative system”, or MUCSys); it is composed of three ends—MUCStudio, MUCView, and MUCServer. MUCStudio aims to construct industrial content with CAD model transformation, simplification, database update, marker design, scene editing, and exportation, while MUCView contains sensor data analysis, real-time localization, scene loading, annotation editing, and virtual–real rendering. MUCServer—as the bridge between MUCStudio and MUCView—presents collaborative and database services. To achieve this, we implemented the algorithms of local map establishment, global map registration, optimization, and network synchronization. The system provides AR services for diverse industrial processes via three collaborative ways—remote support, collaborative annotation, and editing. According to the system, applications for cutting machines were presented to improve efficiency and reduce costs, covering cutting head designs, production line sales, and cutting machine inspections. Finally, a user study was performed to prove the usage experience of the system.

Photos taken in unconstrained tourist environments often present challenges for accurate 3D scene reconstruction due to variable appearances and transient occlusions, which can introduce artifacts in novel view synthesis. Recently, in-the-wild 3D scene reconstruction has been achieved realistic rendering with Neural Radiance Fields (NeRFs). With the advancement of 3D Gaussian Splatting (3DGS), some methods also attempt to reconstruct 3D scenes from unconstrained photo collections and achieve real-time rendering. However, the rapid convergence of 3DGS is misaligned with the slower convergence of neural network-based appearance encoder and transient mask predictor, hindering the reconstruction efficiency. To address this, we propose a novel sky-aware framework for scene reconstruction from unconstrained photo collection using 3DGS. Firstly, we observe that the learnable per-image transient mask predictor in previous work is unnecessary. By introducing a simple yet efficient greedy supervision strategy, we directly utilize the pseudo mask generated by a pretrained semantic segmentation network as the transient mask, thereby achieving more efficient and higher quality in-the-wild 3D scene reconstruction. Secondly, we find that separately estimating appearance embeddings for the sky and building significantly improves reconstruction efficiency and accuracy. We analyze the underlying reasons and introduce a neural sky module to generate diverse skies from latent sky embeddings extract from unconstrained images. Finally, we propose a mutual distillation learning strategy to constrain sky and building appearance embeddings within the same latent space, further enhancing reconstruction efficiency and quality. Extensive experiments on multiple datasets demonstrate that the proposed framework outperforms existing methods in novel view and appearance synthesis, offering superior rendering quality with faster convergence and rendering speed.