  Semantic segmentation of point clouds generates comprehensive understanding
of scenes through densely predicting the category for each point. Due to the
unicity of receptive field, semantic segmentation of point clouds remains
challenging for the expression of multi-receptive field features, which brings
about the misclassification of instances with similar spatial structures. In
this paper, we propose a graph convolutional network DGFA-Net rooted in dilated
graph feature aggregation (DGFA), guided by multi-basis aggregation loss
(MALoss) calculated through Pyramid Decoders. To configure multi-receptive
field features, DGFA which takes the proposed dilated graph convolution
(DGConv) as its basic building block, is designed to aggregate multi-scale
feature representation by capturing dilated graphs with various receptive
regions. By simultaneously considering penalizing the receptive field
information with point sets of different resolutions as calculation bases, we
introduce Pyramid Decoders driven by MALoss for the diversity of receptive
field bases. Combining these two aspects, DGFA-Net significantly improves the
segmentation performance of instances with similar spatial structures.
Experiments on S3DIS, ShapeNetPart and Toronto-3D show that DGFA-Net
outperforms the baseline approach, achieving a new state-of-the-art
segmentation performance.
