透過LiDAR視角:一種特徵豐富且具不確定性感知的地面點雲分割註釋流程
Through the Perspective of LiDAR: A Feature-Enriched and Uncertainty-Aware Annotation Pipeline for Terrestrial Point Cloud Segmentation
October 8, 2025
作者: Fei Zhang, Rob Chancia, Josie Clapp, Amirhossein Hassanzadeh, Dimah Dera, Richard MacKenzie, Jan van Aardt
cs.AI
摘要
地面激光扫描(TLS)点云的精确语义分割受限于昂贵的手动标注成本。我们提出了一种半自动化、不确定性感知的流程,该流程整合了球面投影、特征增强、集成学习及针对性标注,以在保持高精度的同时减少标注工作量。我们的方法将三维点投影至二维球面网格,通过多源特征丰富像素信息,并训练一组分割网络以生成伪标签和不确定性图,后者用于指导模糊区域的标注。二维输出结果被反向投影至三维空间,产生密集标注的点云,并辅以三层可视化套件(二维特征图、三维着色点云及紧凑虚拟球体)以实现快速分类和审阅指导。利用此流程,我们构建了Mangrove3D,一个针对红树林的语义分割TLS数据集。我们进一步评估了数据效率和特征重要性,以解答两个关键问题:(1)需要多少标注数据,(2)哪些特征最为重要。结果表明,性能在约12次标注扫描后趋于饱和,几何特征贡献最大,且紧凑的九通道堆叠几乎捕捉了所有判别力,平均交并比(mIoU)稳定在约0.76。最后,通过在ForestSemantic和Semantic3D上的跨数据集测试,我们验证了特征增强策略的泛化能力。
我们的贡献包括:(i)一套稳健的、不确定性感知的TLS标注流程及可视化工具;(ii)Mangrove3D数据集;以及(iii)关于数据效率和特征重要性的实证指导,从而为生态监测及其他领域实现可扩展、高质量的TLS点云分割提供了支持。数据集及处理脚本已公开于https://fz-rit.github.io/through-the-lidars-eye/。
English
Accurate semantic segmentation of terrestrial laser scanning (TLS) point
clouds is limited by costly manual annotation. We propose a semi-automated,
uncertainty-aware pipeline that integrates spherical projection, feature
enrichment, ensemble learning, and targeted annotation to reduce labeling
effort, while sustaining high accuracy. Our approach projects 3D points to a 2D
spherical grid, enriches pixels with multi-source features, and trains an
ensemble of segmentation networks to produce pseudo-labels and uncertainty
maps, the latter guiding annotation of ambiguous regions. The 2D outputs are
back-projected to 3D, yielding densely annotated point clouds supported by a
three-tier visualization suite (2D feature maps, 3D colorized point clouds, and
compact virtual spheres) for rapid triage and reviewer guidance. Using this
pipeline, we build Mangrove3D, a semantic segmentation TLS dataset for mangrove
forests. We further evaluate data efficiency and feature importance to address
two key questions: (1) how much annotated data are needed and (2) which
features matter most. Results show that performance saturates after ~12
annotated scans, geometric features contribute the most, and compact
nine-channel stacks capture nearly all discriminative power, with the mean
Intersection over Union (mIoU) plateauing at around 0.76. Finally, we confirm
the generalization of our feature-enrichment strategy through cross-dataset
tests on ForestSemantic and Semantic3D.
Our contributions include: (i) a robust, uncertainty-aware TLS annotation
pipeline with visualization tools; (ii) the Mangrove3D dataset; and (iii)
empirical guidance on data efficiency and feature importance, thus enabling
scalable, high-quality segmentation of TLS point clouds for ecological
monitoring and beyond. The dataset and processing scripts are publicly
available at https://fz-rit.github.io/through-the-lidars-eye/.