Point-cloud data collected in real-world applications are often incomplete.
Data is typically missing due to objects being observed from partial
viewpoints, which only capture a specific perspective or angle. Additionally,
data can be incomplete due to occlusion and low-resolution sampling. Existing
completion approaches rely on datasets of predefined objects to guide the
completion of noisy and incomplete, point clouds. However, these approaches
perform poorly when tested on Out-Of-Distribution (OOD) objects, that are
poorly represented in the training dataset. Here we leverage recent advances in
text-guided image generation, which lead to major breakthroughs in text-guided
shape generation. We describe an approach called SDS-Complete that uses a
pre-trained text-to-image diffusion model and leverages the text semantics of a
given incomplete point cloud of an object, to obtain a complete surface
representation. SDS-Complete can complete a variety of objects using test-time
optimization without expensive collection of 3D information. We evaluate SDS
Complete on incomplete scanned objects, captured by real-world depth sensors
and LiDAR scanners. We find that it effectively reconstructs objects that are
absent from common datasets, reducing Chamfer loss by 50% on average compared
with current methods. Project page: this https URL

本文提出了一种名为 SDS-Complete 的方法，该方法利用预训练的文本到图像扩散模型，借助给定不完整点云对象的文本语义获取完整的表面表示，其可以有效地重建通过现实世界深度传感器和 LiDAR 扫描仪捕获的不完整扫描物体，相较于当前方法平均减少了 50％的 Chamfer 损失。

使用预训练文本到图像扩散模型完成点云

Point-Cloud Completion with Pretrained Text-to-image Diffusion Models

With the advancement of deep neural networks and computer vision-based Human
Activity Recognition, employment of Point-Cloud Data technologies (LiDAR,
mmWave) has seen a lot interests due to its privacy preserving nature. Given
the high promise of accurate PCD technologies, we develop, PALMAR, a
multiple-inhabitant activity recognition system by employing efficient signal
processing and novel machine learning techniques to track individual person
towards developing an adaptive multi-inhabitant tracking and HAR system. More
specifically, we propose (i) a voxelized feature representation-based real-time
PCD fine-tuning method, (ii) efficient clustering (DBSCAN and BIRCH), Adaptive
Order Hidden Markov Model based multi-person tracking and crossover ambiguity
reduction techniques and (iii) novel adaptive deep learning-based domain
adaptation technique to improve the accuracy of HAR in presence of data
scarcity and diversity (device, location and population diversity). We
experimentally evaluate our framework and systems using (i) a real-time PCD
collected by three devices (3D LiDAR and 79 GHz mmWave) from 6 participants,
(ii) one publicly available 3D LiDAR activity data (28 participants) and (iii)
an embedded hardware prototype system which provided promising HAR performances
in multi-inhabitants (96%) scenario with a 63% improvement of multi-person
tracking than state-of-art framework without losing significant system
performances in the edge computing device.

本文介绍了使用点云数据技术和机器学习技术实现的多居住者活动识别系统 PALMAR，该系统采用了分特征呈现的实时 PCD 微调方法、高效聚类技术、自适应多人追踪、区分多义歧义并提高识别准确性的领域自适应技术等多种创新技术，能够在多人场景中显著提高多人追踪准确率，且效果令人满意。