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dc.contributorDepartment of Computingen_US
dc.contributor.advisorZhang, Lei (COMP)en_US
dc.creatorHe, Chenhang-
dc.identifier.urihttps://theses.lib.polyu.edu.hk/handle/200/12714-
dc.languageEnglishen_US
dc.publisherHong Kong Polytechnic Universityen_US
dc.rightsAll rights reserveden_US
dc.titleEfficient feature learning for point cloud-based 3D object detectionen_US
dcterms.abstract3D object detection is one of the fundamental techniques for autonomous driving, which aims to locate and track objects such as vehicles, pedestrians, and cyclists in real-time. While image-based computer vision techniques have been successfully used in many scenarios, most autonomous driving systems still rely on high-end LiDAR sensors to provide 3D measurements for high-precision object detection. However, processing the unstructured and unordered data from LiDAR point clouds is challenging and requires efficient feature extraction models.en_US
dcterms.abstractIn this thesis, we explore different efficient feature learning algorithm for point cloud-based 3D object detection. We first explore the trade-offs between point-based and voxel-based representations for point cloud detection models. To combine the strengths of both approaches, we propose a novel structure-aware single-stage detector (SASSD) that enables voxel-based models to learn fine-grained details from point-based representation with an auxiliary network. This results in a significant improvement in detection accuracy without increasing computational cost.en_US
dcterms.abstractWe then investigate the use of transformer-based models for feature extraction on point cloud data. While transformers are well-suited for large receptive regions, they are challenging to apply to sparse and spatially imbalanced point cloud data. To overcome this issue, we propose a voxel set transformer (VoxSeT) model that performs attention modeling on multiple voxel sets with arbitrary number of points. Our VoxSeT model outperforms commonly used sparse convolutional models in both accuracy and efficiency and is straightforward to deploy.en_US
dcterms.abstractWe further explore how to enhance 3D object detection performance with sequential point cloud data. We introduce a motion-guided sequential fusion (MSF) method that efficiently fuses multi-frame features through a proposal propagation algorithm. This approach achieves leading performance on the Waymo dataset, while incurring similar costs to a single-frame detector.en_US
dcterms.abstractFinally, we present a novel-view synthesis-based augmentation framework, namely AugMono3D, for monocular 3D object detection. We leverage point clouds to re-construct the scene geometry of a camera image and generate the synthetic image data by augmenting camera views at multiple virtual depths. By training on a large number of synthetic images with virtual depth, our framework consistently improves the detection accuracy.en_US
dcterms.abstractOverall, the proposed four methods demonstrate their effectiveness in learning efficient point cloud features for high-quality 3D object detection. We evaluate our methods on benchmark datasets such as Waymo and KITTI and show significant improvements in accuracy and efficiency.en_US
dcterms.extentxix, 115 pages : color illustrationsen_US
dcterms.isPartOfPolyU Electronic Thesesen_US
dcterms.issued2023en_US
dcterms.educationalLevelPh.D.en_US
dcterms.educationalLevelAll Doctorateen_US
dcterms.LCSHComputer visionen_US
dcterms.LCSHImage analysis -- Data processingen_US
dcterms.LCSHMachine learningen_US
dcterms.LCSHHong Kong Polytechnic University -- Dissertationsen_US
dcterms.accessRightsopen accessen_US

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Please use this identifier to cite or link to this item: https://theses.lib.polyu.edu.hk/handle/200/12714