Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Adaptive Hierarchical Down-Sampling for Point Cloud Classification   While several convolution-like operators have recently been proposed for
extracting features out of point clouds, down-sampling an unordered point cloud
in a deep neural network has not been rigorously studied. Existing methods
down-sample the points regardless of their importance for the output. As a
result, some important points in the point cloud may be removed, while less
valuable points may be passed to the next layers. In contrast, adaptive
down-sampling methods sample the points by taking into account the importance
of each point, which varies based on the application, task and training data.
In this paper, we propose a permutation-invariant learning-based adaptive
down-sampling layer, called Critical Points Layer (CPL), which reduces the
number of points in an unordered point cloud while retaining the important
points. Unlike most graph-based point cloud down-sampling methods that use
$k$-NN search algorithm to find the neighbouring points, CPL is a global
down-sampling method, rendering it computationally very efficient. The proposed
layer can be used along with any graph-based point cloud convolution layer to
form a convolutional neural network, dubbed CP-Net in this paper. We introduce
a CP-Net for $3$D object classification that achieves the best accuracy for the
ModelNet$40$ dataset among point cloud-based methods, which validates the
effectiveness of the CPL.

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The categories of this paper are: acc-phys
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-lat
0
The categories of this paper are: hep-ph
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
29
The categories of this paper are: funct-an
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The categories of this paper are: math-ph
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The categories of this paper are: solv-int
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The categories of this paper are: hep-th
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The categories of this paper are: cond-mat
30
The categories of this paper are: q-alg
3
The categories of this paper are: physics
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The categories of this paper are: stat