Files
dgl/examples/pytorch/pointcloud/pointnet/pointnet2.py
Hongzhi (Steve), Chen 704bcaf6dd examples (#5323)
Co-authored-by: Ubuntu <ubuntu@ip-172-31-28-63.ap-northeast-1.compute.internal>
2023-02-19 08:35:15 +08:00

448 lines
13 KiB
Python

import dgl
import dgl.function as fn
import numpy as np
import torch
import torch.nn as nn
import torch.nn.functional as F
from dgl.geometry import (
farthest_point_sampler,
) # dgl.geometry.pytorch -> dgl.geometry
from torch.autograd import Variable
"""
Part of the code are adapted from
https://github.com/yanx27/Pointnet_Pointnet2_pytorch
"""
def square_distance(src, dst):
"""
Adapted from https://github.com/yanx27/Pointnet_Pointnet2_pytorch
"""
B, N, _ = src.shape
_, M, _ = dst.shape
dist = -2 * torch.matmul(src, dst.permute(0, 2, 1))
dist += torch.sum(src**2, -1).view(B, N, 1)
dist += torch.sum(dst**2, -1).view(B, 1, M)
return dist
def index_points(points, idx):
"""
Adapted from https://github.com/yanx27/Pointnet_Pointnet2_pytorch
"""
device = points.device
B = points.shape[0]
view_shape = list(idx.shape)
view_shape[1:] = [1] * (len(view_shape) - 1)
repeat_shape = list(idx.shape)
repeat_shape[0] = 1
batch_indices = (
torch.arange(B, dtype=torch.long)
.to(device)
.view(view_shape)
.repeat(repeat_shape)
)
new_points = points[batch_indices, idx, :]
return new_points
class FixedRadiusNearNeighbors(nn.Module):
"""
Ball Query - Find the neighbors with-in a fixed radius
"""
def __init__(self, radius, n_neighbor):
super(FixedRadiusNearNeighbors, self).__init__()
self.radius = radius
self.n_neighbor = n_neighbor
def forward(self, pos, centroids):
"""
Adapted from https://github.com/yanx27/Pointnet_Pointnet2_pytorch
"""
device = pos.device
B, N, _ = pos.shape
center_pos = index_points(pos, centroids)
_, S, _ = center_pos.shape
group_idx = (
torch.arange(N, dtype=torch.long)
.to(device)
.view(1, 1, N)
.repeat([B, S, 1])
)
sqrdists = square_distance(center_pos, pos)
group_idx[sqrdists > self.radius**2] = N
group_idx = group_idx.sort(dim=-1)[0][:, :, : self.n_neighbor]
group_first = (
group_idx[:, :, 0].view(B, S, 1).repeat([1, 1, self.n_neighbor])
)
mask = group_idx == N
group_idx[mask] = group_first[mask]
return group_idx
class FixedRadiusNNGraph(nn.Module):
"""
Build NN graph
"""
def __init__(self, radius, n_neighbor):
super(FixedRadiusNNGraph, self).__init__()
self.radius = radius
self.n_neighbor = n_neighbor
self.frnn = FixedRadiusNearNeighbors(radius, n_neighbor)
def forward(self, pos, centroids, feat=None):
dev = pos.device
group_idx = self.frnn(pos, centroids)
B, N, _ = pos.shape
glist = []
for i in range(B):
center = torch.zeros((N)).to(dev)
center[centroids[i]] = 1
src = group_idx[i].contiguous().view(-1)
dst = centroids[i].view(-1, 1).repeat(1, self.n_neighbor).view(-1)
unified = torch.cat([src, dst])
uniq, inv_idx = torch.unique(unified, return_inverse=True)
src_idx = inv_idx[: src.shape[0]]
dst_idx = inv_idx[src.shape[0] :]
g = dgl.graph((src_idx, dst_idx))
g.ndata["pos"] = pos[i][uniq]
g.ndata["center"] = center[uniq]
if feat is not None:
g.ndata["feat"] = feat[i][uniq]
glist.append(g)
bg = dgl.batch(glist)
return bg
class RelativePositionMessage(nn.Module):
"""
Compute the input feature from neighbors
"""
def __init__(self, n_neighbor):
super(RelativePositionMessage, self).__init__()
self.n_neighbor = n_neighbor
def forward(self, edges):
pos = edges.src["pos"] - edges.dst["pos"]
if "feat" in edges.src:
res = torch.cat([pos, edges.src["feat"]], 1)
else:
res = pos
return {"agg_feat": res}
class PointNetConv(nn.Module):
"""
Feature aggregation
"""
def __init__(self, sizes, batch_size):
super(PointNetConv, self).__init__()
self.batch_size = batch_size
self.conv = nn.ModuleList()
self.bn = nn.ModuleList()
for i in range(1, len(sizes)):
self.conv.append(nn.Conv2d(sizes[i - 1], sizes[i], 1))
self.bn.append(nn.BatchNorm2d(sizes[i]))
def forward(self, nodes):
shape = nodes.mailbox["agg_feat"].shape
h = (
nodes.mailbox["agg_feat"]
.view(self.batch_size, -1, shape[1], shape[2])
.permute(0, 3, 2, 1)
)
for conv, bn in zip(self.conv, self.bn):
h = conv(h)
h = bn(h)
h = F.relu(h)
h = torch.max(h, 2)[0]
feat_dim = h.shape[1]
h = h.permute(0, 2, 1).reshape(-1, feat_dim)
return {"new_feat": h}
def group_all(self, pos, feat):
"""
Feature aggregation and pooling for the non-sampling layer
"""
if feat is not None:
h = torch.cat([pos, feat], 2)
else:
h = pos
B, N, D = h.shape
_, _, C = pos.shape
new_pos = torch.zeros(B, 1, C)
h = h.permute(0, 2, 1).view(B, -1, N, 1)
for conv, bn in zip(self.conv, self.bn):
h = conv(h)
h = bn(h)
h = F.relu(h)
h = torch.max(h[:, :, :, 0], 2)[0] # [B,D]
return new_pos, h
class SAModule(nn.Module):
"""
The Set Abstraction Layer
"""
def __init__(
self,
npoints,
batch_size,
radius,
mlp_sizes,
n_neighbor=64,
group_all=False,
):
super(SAModule, self).__init__()
self.group_all = group_all
if not group_all:
self.npoints = npoints
self.frnn_graph = FixedRadiusNNGraph(radius, n_neighbor)
self.message = RelativePositionMessage(n_neighbor)
self.conv = PointNetConv(mlp_sizes, batch_size)
self.batch_size = batch_size
def forward(self, pos, feat):
if self.group_all:
return self.conv.group_all(pos, feat)
centroids = farthest_point_sampler(pos, self.npoints)
g = self.frnn_graph(pos, centroids, feat)
g.update_all(self.message, self.conv)
mask = g.ndata["center"] == 1
pos_dim = g.ndata["pos"].shape[-1]
feat_dim = g.ndata["new_feat"].shape[-1]
pos_res = g.ndata["pos"][mask].view(self.batch_size, -1, pos_dim)
feat_res = g.ndata["new_feat"][mask].view(self.batch_size, -1, feat_dim)
return pos_res, feat_res
class SAMSGModule(nn.Module):
"""
The Set Abstraction Multi-Scale grouping Layer
"""
def __init__(
self, npoints, batch_size, radius_list, n_neighbor_list, mlp_sizes_list
):
super(SAMSGModule, self).__init__()
self.batch_size = batch_size
self.group_size = len(radius_list)
self.npoints = npoints
self.frnn_graph_list = nn.ModuleList()
self.message_list = nn.ModuleList()
self.conv_list = nn.ModuleList()
for i in range(self.group_size):
self.frnn_graph_list.append(
FixedRadiusNNGraph(radius_list[i], n_neighbor_list[i])
)
self.message_list.append(
RelativePositionMessage(n_neighbor_list[i])
)
self.conv_list.append(PointNetConv(mlp_sizes_list[i], batch_size))
def forward(self, pos, feat):
centroids = farthest_point_sampler(pos, self.npoints)
feat_res_list = []
for i in range(self.group_size):
g = self.frnn_graph_list[i](pos, centroids, feat)
g.update_all(self.message_list[i], self.conv_list[i])
mask = g.ndata["center"] == 1
pos_dim = g.ndata["pos"].shape[-1]
feat_dim = g.ndata["new_feat"].shape[-1]
if i == 0:
pos_res = g.ndata["pos"][mask].view(
self.batch_size, -1, pos_dim
)
feat_res = g.ndata["new_feat"][mask].view(
self.batch_size, -1, feat_dim
)
feat_res_list.append(feat_res)
feat_res = torch.cat(feat_res_list, 2)
return pos_res, feat_res
class PointNet2FP(nn.Module):
"""
The Feature Propagation Layer
"""
def __init__(self, input_dims, sizes):
super(PointNet2FP, self).__init__()
self.convs = nn.ModuleList()
self.bns = nn.ModuleList()
sizes = [input_dims] + sizes
for i in range(1, len(sizes)):
self.convs.append(nn.Conv1d(sizes[i - 1], sizes[i], 1))
self.bns.append(nn.BatchNorm1d(sizes[i]))
def forward(self, x1, x2, feat1, feat2):
"""
Adapted from https://github.com/yanx27/Pointnet_Pointnet2_pytorch
Input:
x1: input points position data, [B, N, C]
x2: sampled input points position data, [B, S, C]
feat1: input points data, [B, N, D]
feat2: input points data, [B, S, D]
Return:
new_feat: upsampled points data, [B, D', N]
"""
B, N, C = x1.shape
_, S, _ = x2.shape
if S == 1:
interpolated_feat = feat2.repeat(1, N, 1)
else:
dists = square_distance(x1, x2)
dists, idx = dists.sort(dim=-1)
dists, idx = dists[:, :, :3], idx[:, :, :3] # [B, N, 3]
dist_recip = 1.0 / (dists + 1e-8)
norm = torch.sum(dist_recip, dim=2, keepdim=True)
weight = dist_recip / norm
interpolated_feat = torch.sum(
index_points(feat2, idx) * weight.view(B, N, 3, 1), dim=2
)
if feat1 is not None:
new_feat = torch.cat([feat1, interpolated_feat], dim=-1)
else:
new_feat = interpolated_feat
new_feat = new_feat.permute(0, 2, 1) # [B, D, S]
for i, conv in enumerate(self.convs):
bn = self.bns[i]
new_feat = F.relu(bn(conv(new_feat)))
return new_feat
class PointNet2SSGCls(nn.Module):
def __init__(
self, output_classes, batch_size, input_dims=3, dropout_prob=0.4
):
super(PointNet2SSGCls, self).__init__()
self.input_dims = input_dims
self.sa_module1 = SAModule(
512, batch_size, 0.2, [input_dims, 64, 64, 128]
)
self.sa_module2 = SAModule(
128, batch_size, 0.4, [128 + 3, 128, 128, 256]
)
self.sa_module3 = SAModule(
None, batch_size, None, [256 + 3, 256, 512, 1024], group_all=True
)
self.mlp1 = nn.Linear(1024, 512)
self.bn1 = nn.BatchNorm1d(512)
self.drop1 = nn.Dropout(dropout_prob)
self.mlp2 = nn.Linear(512, 256)
self.bn2 = nn.BatchNorm1d(256)
self.drop2 = nn.Dropout(dropout_prob)
self.mlp_out = nn.Linear(256, output_classes)
def forward(self, x):
if x.shape[-1] > 3:
pos = x[:, :, :3]
feat = x[:, :, 3:]
else:
pos = x
feat = None
pos, feat = self.sa_module1(pos, feat)
pos, feat = self.sa_module2(pos, feat)
_, h = self.sa_module3(pos, feat)
h = self.mlp1(h)
h = self.bn1(h)
h = F.relu(h)
h = self.drop1(h)
h = self.mlp2(h)
h = self.bn2(h)
h = F.relu(h)
h = self.drop2(h)
out = self.mlp_out(h)
return out
class PointNet2MSGCls(nn.Module):
def __init__(
self, output_classes, batch_size, input_dims=3, dropout_prob=0.4
):
super(PointNet2MSGCls, self).__init__()
self.input_dims = input_dims
self.sa_msg_module1 = SAMSGModule(
512,
batch_size,
[0.1, 0.2, 0.4],
[16, 32, 128],
[
[input_dims, 32, 32, 64],
[input_dims, 64, 64, 128],
[input_dims, 64, 96, 128],
],
)
self.sa_msg_module2 = SAMSGModule(
128,
batch_size,
[0.2, 0.4, 0.8],
[32, 64, 128],
[
[320 + 3, 64, 64, 128],
[320 + 3, 128, 128, 256],
[320 + 3, 128, 128, 256],
],
)
self.sa_module3 = SAModule(
None, batch_size, None, [640 + 3, 256, 512, 1024], group_all=True
)
self.mlp1 = nn.Linear(1024, 512)
self.bn1 = nn.BatchNorm1d(512)
self.drop1 = nn.Dropout(dropout_prob)
self.mlp2 = nn.Linear(512, 256)
self.bn2 = nn.BatchNorm1d(256)
self.drop2 = nn.Dropout(dropout_prob)
self.mlp_out = nn.Linear(256, output_classes)
def forward(self, x):
if x.shape[-1] > 3:
pos = x[:, :, :3]
feat = x[:, :, 3:]
else:
pos = x
feat = None
pos, feat = self.sa_msg_module1(pos, feat)
pos, feat = self.sa_msg_module2(pos, feat)
_, h = self.sa_module3(pos, feat)
h = self.mlp1(h)
h = self.bn1(h)
h = F.relu(h)
h = self.drop1(h)
h = self.mlp2(h)
h = self.bn2(h)
h = F.relu(h)
h = self.drop2(h)
out = self.mlp_out(h)
return out