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Leveraging Graph Convolutional Networks for Point Cloud UpsamplingQian, Guocheng 16 November 2020 (has links)
Due to hardware limitations, 3D sensors like LiDAR often produce sparse and
noisy point clouds. Point cloud upsampling is the task of converting such point
clouds into dense and clean ones. This thesis tackles the problem of point cloud upsampling
using deep neural networks. The effectiveness of a point cloud upsampling
neural network heavily relies on the upsampling module and the feature extractor used
therein. In this thesis, I propose a novel point upsampling module, called NodeShuffle.
NodeShuffle leverages Graph Convolutional Networks (GCNs) to better encode
local point information from point neighborhoods. NodeShuffle is versatile and can
be incorporated into any point cloud upsampling pipeline. Extensive experiments
show how NodeShuffle consistently improves the performance of previous upsampling
methods. I also propose a new GCN-based multi-scale feature extractor, called Inception
DenseGCN. By aggregating features at multiple scales, Inception DenseGCN
learns a hierarchical feature representation and enables further performance gains. I
combine Inception DenseGCN with NodeShuffle into the proposed point cloud upsampling
network called PU-GCN. PU-GCN sets new state-of-art performance with
much fewer parameters and more efficient inference.
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Knowledge-based 3D point clouds processingTruong, Quoc Hung 15 November 2013 (has links) (PDF)
The modeling of real-world scenes through capturing 3D digital data has proven to be both useful andapplicable in a variety of industrial and surveying applications. Entire scenes are generally capturedby laser scanners and represented by large unorganized point clouds possibly along with additionalphotogrammetric data. A typical challenge in processing such point clouds and data lies in detectingand classifying objects that are present in the scene. In addition to the presence of noise, occlusionsand missing data, such tasks are often hindered by the irregularity of the capturing conditions bothwithin the same dataset and from one data set to another. Given the complexity of the underlyingproblems, recent processing approaches attempt to exploit semantic knowledge for identifying andclassifying objects. In the present thesis, we propose a novel approach that makes use of intelligentknowledge management strategies for processing of 3D point clouds as well as identifying andclassifying objects in digitized scenes. Our approach extends the use of semantic knowledge to allstages of the processing, including the guidance of the individual data-driven processing algorithms.The complete solution consists in a multi-stage iterative concept based on three factors: the modeledknowledge, the package of algorithms, and a classification engine. The goal of the present work isto select and guide algorithms following an adaptive and intelligent strategy for detecting objects inpoint clouds. Experiments with two case studies demonstrate the applicability of our approach. Thestudies were carried out on scans of the waiting area of an airport and along the tracks of a railway.In both cases the goal was to detect and identify objects within a defined area. Results show that ourapproach succeeded in identifying the objects of interest while using various data types
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Knowledge-based 3D point clouds processing / Traitement 3D de nuages de points basé sur la connaissanceTruong, Quoc Hung 15 November 2013 (has links)
La modélisation de scènes réelles à travers la capture de données numériques 3D a été prouvée à la fois utile et applicable dans une variété d’applications. Des scènes entières sont généralement numérisées par des scanners laser et représentées par des grands nuages de points non organisés souvent accompagnés de données photogrammétriques. Un problème typique dans le traitement de ces nuages et données réside dans la détection et la classification des objets présents dans la scène. Ces tâches sont souvent entravées par la variabilité des conditions de capture des données, la présence de bruit, les occlusions ainsi que les données manquantes. Compte tenu de la complexité des problèmes sous-jacents, les approches de traitement récentes tentent d’exploiter les connaissances sémantiques pour identifier et classer les objets. Dans cette thèse, nous proposons une nouvelle approche qui fait appel à des stratégies intelligentes de gestion des connaissances pour le traitement des nuages de points 3D ainsi que l’identification et la classification des objets dans les scènes numérisées. Notre approche étend l’utilisation des connaissances sémantiques à toutes les étapes du traitement, y compris le choix et le guidage des algorithmes de traitement axées sur les données individuelles. Notre solution constitue un concept multi-étape itératif sur la base de trois facteurs : la connaissance modélisée, un ensemble d’algorithmes de traitement, et un moteur de classification. L’objectif de ce travail est de sélectionner et d’orienter les algorithmes de manière adaptative et intelligente pour détecter des objets dans les nuages de points. Des expériences avec deux études de cas démontrent l’applicabilité de notre approche. Les études ont été réalisées sur des analyses de la salle d’attente d’un aéroport et le long des voies de chemin de fer. Dans les deux cas, l’objectif était de détecter et d’identifier des objets dans une zone définie. Les résultats montrent que notre approche a réussi à identifier les objets d’intérêt tout en utilisant différents types de données / The modeling of real-world scenes through capturing 3D digital data has proven to be both useful andapplicable in a variety of industrial and surveying applications. Entire scenes are generally capturedby laser scanners and represented by large unorganized point clouds possibly along with additionalphotogrammetric data. A typical challenge in processing such point clouds and data lies in detectingand classifying objects that are present in the scene. In addition to the presence of noise, occlusionsand missing data, such tasks are often hindered by the irregularity of the capturing conditions bothwithin the same dataset and from one data set to another. Given the complexity of the underlyingproblems, recent processing approaches attempt to exploit semantic knowledge for identifying andclassifying objects. In the present thesis, we propose a novel approach that makes use of intelligentknowledge management strategies for processing of 3D point clouds as well as identifying andclassifying objects in digitized scenes. Our approach extends the use of semantic knowledge to allstages of the processing, including the guidance of the individual data-driven processing algorithms.The complete solution consists in a multi-stage iterative concept based on three factors: the modeledknowledge, the package of algorithms, and a classification engine. The goal of the present work isto select and guide algorithms following an adaptive and intelligent strategy for detecting objects inpoint clouds. Experiments with two case studies demonstrate the applicability of our approach. Thestudies were carried out on scans of the waiting area of an airport and along the tracks of a railway.In both cases the goal was to detect and identify objects within a defined area. Results show that ourapproach succeeded in identifying the objects of interest while using various data types
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