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计算机工程 ›› 2024, Vol. 50 ›› Issue (9): 255-265. doi: 10.19678/j.issn.1000-3428.0067589

• 图形图像处理 • 上一篇    下一篇

基于可变形三维图卷积的轻量级点云分类研究

蔡俊民1,*(), 梁正友1,2, 孙宇1, 陈子奥1   

  1. 1. 广西大学计算机与电子信息学院, 广西 南宁 530004
    2. 广西大学广西多媒体通信与网络技术重点实验室, 广西 南宁 530004
  • 收稿日期:2023-05-10 出版日期:2024-09-15 发布日期:2024-01-25
  • 通讯作者: 蔡俊民
  • 基金资助:
    国家自然科学基金面上项目(62171145)

Research on Lightweight Point Cloud Classification Based on Deformable 3D Graph Convolution

CAI Junmin1,*(), LIANG Zhengyou1,2, SUN Yu1, CHEN Ziao1   

  1. 1. School of Computer and Electronics Information, Guangxi University, Nanning 530004, Guangxi, China
    2. Guangxi Key Laboratory of Multimedia Communications and Network Technology, Guangxi University, Nanning 530004, Guangxi, China
  • Received:2023-05-10 Online:2024-09-15 Published:2024-01-25
  • Contact: CAI Junmin

摘要:

现有深度学习方法在处理点云分类任务时, 依赖于点的绝对坐标, 存在模型复杂度较大的问题。对此, 提出一种轻量级的点云分类网络DMGCN-3D。使用自适应空洞K近邻(KNN)算法构造图结构, 尽可能捕捉局部更广泛空间的几何结构信息, 并减少计算开支; 构造可变形三维图卷积, 引入可学习的点与点之间的方向向量来获取相对特性, 在特征提取过程中保证点云的置换不变性与尺度不变性; 构建多头自注意力模块, 通过残差结构将分组变换注意力(GSA)与多层感知机(MLP)相结合, MLP有助于保持原始点云信息的完整性, GSA使得网络能够学习特征内部的自相关性, 在提高特征表达能力的同时降低参数总量; 使用空间变换网络结合MLP来学习点云特征; 对所提取的特征进行融合以得到更综合的特征, 将其用于点云分类。实验结果表明, DMGCN-3D在ModelNet10、ModelNet40、ScanObjectNN数据集上的总体精度分别达到96.5%、94.7%、81.9%, 比DGCNN分别提高2.9、2.1、3.8个百分点, 参数总量相比DGCNN、LDGCNN、3DGCN模型分别降低52.9%、23.9%、3.3%, 且DMGCN-3D能够保持较高的鲁棒性。

关键词: 点云分类, 可变形三维图卷积, 自适应, 多头自注意力, 轻量级网络

Abstract:

Existing deep learning methods rely on absolute point coordinates when addressing point cloud classification tasks, which encounter the large model complexity problem. To address this challenge, a lightweight point cloud classification network called DMGCN-3D is proposed herein. The adaptive hollow K-Nearest Neighbor (KNN) algorithm is used to construct the graph structure, capture geometric structure information regarding the local wider space, and reduce calculation costs. A deformable 3-Dimensional (3D) graph convolution is constructed, and the learnable direction vector between points is introduced to obtain relative characteristics between points. The displacement and scale invariances of point clouds are guaranteed during the feature extraction process. A multi-head self-attention module is constructed, and the residual structure is combined with Group Shift Attention (GSA) and the Multi-Layer Perceptron (MLP) network. The MLP assists in maintaining the integrity of original point cloud information, and the GSA enables the network to learn the internal autocorrelation of features, which improves feature expression capability and reduces the total number of model parameters. A spatial transformation network combined with the MLP is used to learn point cloud features. Finally, the extracted features are fused to obtain more comprehensive point cloud classification features. The experimental results demonstrate that the overall accuracies of DMGCN-3D on ModelNet10, ModelNet40, and ScanObjectNN are 96.5%, 94.7%, and 81.9%, respectively, which is 2.9, 2.1, and 3.8 percentage points higher than those of the DGCNN. Compared with DGCNN, LDGCNN, and 3DGCN, the total number of parameters is reduced by 52.9%, 23.9%, and 3.3%, respectively. Additionally, high robustness is maintained, which demonstrates an improvement on that of existing advanced methods.

Key words: point cloud classification, deformable 3D graph convolution, self-adaption, multiple head self-attention, lightweight network