Mixed Reality (MR) telecollaboration aims to enable users to share local objects as real-time synchronized virtual replicas to remote partners and collaborate on physical tasks as if they were co-located. However, in everyday scenarios with mobile and easy-to-setup MR devices, visualizing shared objects in a single modality, ranging from 2D images to 3D reconstruction, struggles to simultaneously optimize all the aspects of Spatiality, Fidelity, and Real-time performance. To overcome this issue, existing methods explore integrating multiple visualization modalities to leverage their respective advantages in subsets of the three aspects. However, they focus on fixed modality combinations without considering user-centered task contexts and workflow, where users may prioritize different aspects of the visualization across task phases. Moreover, they lack support for switching or require manual switching across modalities, which could become disruptive and tiring. In this paper, we propose adapting object visualization based on spatiotemporal contexts in telecollaboration. Specifically, we first couple task type with the user's relative viewing distance as the spatial context, and examine its impact on users' prioritized visualization aspects, and the corresponding switching thresholds. With differing generation speeds of modalities, we then explore temporal switching schemes when the preferred modality is not immediately available. With the obtained design choices, we implement CollabVisAdapt, a proof-of-concept prototype that supports automatic adaptation of object visualization based on spatiotemporal contexts in MR telecollaboration. A user study in remote maintenance verifies the effectiveness of the proposed workflow with adaptive visualization and the usability of the system.

The irregular and chaotically interwoven distributions of vegetation and rock mass in natural environments pose significant challenges for vegetation filtering of rock point clouds, as existing methods struggle with inefficient contextual modeling and insufficient feature discriminability. To address these limitations, we propose a robust vegetation filtering method for rock mass scene point clouds featuring two key innovations: (1) Bidirectional Point Cloud Mamba module that adopts an alternating allocation strategy to divide the sampled superpoints into two complementary groups, and constructs optimized sequences from edge to center for each group via the Traveling Salesman Problem (TSP) algorithm to enable spatially continuous context capture while eliminating dependency on regular geometric priors; (2) Structure-based adaptive Tri-Plane feature representation includes Principal Component Analysis (PCA)-based support plane selection, projective 2D feature mapping, and learnable multi-scale aggregation. By exploiting the distribution differences of rock mass and vegetation structure information in 2D projections while emulating human visual perception mechanisms that rely on optimal viewing perspectives and different scales, this module enables more discriminative feature extraction in complex natural rock-mass scenarios. Extensive comparative and ablation experiments on real-world datasets demonstrate that our method achieves superior accuracy, robustness, and generalization, and excels in preserving intricate details compared to existing methods.