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arXiv 2103.00738cs.CVcs.AI
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FPS-Net:一种用于大规模LiDAR点云分割的卷积融合网络

FPS-Net: A Convolutional Fusion Network for Large-Scale LiDAR Point Cloud Segmentation

Nanyang Technological University(南洋理工大学);University of Macau(澳门大学)

Aoran Xiao, Xiaofei Yang, Shijian Lu, Dayan Guan, Jiaxing Huang

摘要:

基于LiDAR点云的场景理解是自动驾驶汽车安全行驶的关键,通常采用球面投影将三维点云映射为多通道二维图像进行语义分割。大多数现有方法简单地堆叠不同的点属性/模态(例如,坐标、强度、深度等)。作为图像通道,以增加信息容量,但忽略了点属性在不同图像通道中的明显特点。我们设计了FPS-Net,这是一种卷积融合网络,它利用投影图像通道之间的唯一性和差异来进行最佳点云分割。FPS-Net采用编解码器结构。我们不是简单地将多个通道图像堆叠为单个输入,而是将它们分组到不同的模态中,首先分别学习模态特定的特征,然后将学习到的特征映射到一个公共的高维特征空间中进行像素级融合和学习。具体来说,我们设计了一个具有多个感受野的残差密集块作为编码器中的构建块,该构建块保留了每个模态中的详细信息,并有效地学习了分层模态特定和融合特征。在FPS-Net解码器中,我们同样使用递归卷积块将融合特征分层解码到输出空间中,以进行像素级分类。在两个被广泛采用的点云数据集上进行的大量实验表明,与最先进的基于投影的方法相比,FPS-Net实现了优越的语义分割。此外,所提出的模态融合的想法是兼容的典型的基于投影的方法,并可以纳入他们一致的性能改进。

英文摘要:

Scene understanding based on LiDAR point cloud is an essential task for autonomous cars to drive safely, which often employs spherical projection to map 3D point cloud into multi-channel 2D images for semantic segmentation. Most existing methods simply stack different point attributes/modalities (e.g. coordinates, intensity, depth, etc.) as image channels to increase information capacity, but ignore distinct characteristics of point attributes in different image channels. We design FPS-Net, a convolutional fusion network that exploits the uniqueness and discrepancy among the projected image channels for optimal point cloud segmentation. FPS-Net adopts an encoder-decoder structure. Instead of simply stacking multiple channel images as a single input, we group them into different modalities to first learn modality-specific features separately and then map the learned features into a common high-dimensional feature space for pixel-level fusion and learning. Specifically, we design a residual dense block with multiple receptive fields as a building block in the encoder which preserves detailed information in each modality and learns hierarchical modality-specific and fused features effectively. In the FPS-Net decoder, we use a recurrent convolution block likewise to hierarchically decode fused features into output space for pixel-level classification. Extensive experiments conducted on two widely adopted point cloud datasets show that FPS-Net achieves superior semantic segmentation as compared with state-of-the-art projection-based methods. In addition, the proposed modality fusion idea is compatible with typical projection-based methods and can be incorporated into them with consistent performance improvements.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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