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Running
on
Zero
File size: 3,441 Bytes
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import torch
import torch.nn as nn
import torch.nn.functional as F
#Ref: https://github.com/princeton-vl/RAFT/blob/master/core/update.py
class FlowHead(nn.Module):
def __init__(self, input_dim=128, hidden_dim=256):
super(FlowHead, self).__init__()
self.conv1 = nn.Conv2d(input_dim, hidden_dim, 3, padding=1)
self.conv2 = nn.Conv2d(hidden_dim, 2, 3, padding=1)
self.relu = nn.ReLU(inplace=True)
def forward(self, x):
return self.conv2(self.relu(self.conv1(x)))
class SepConvGRU(nn.Module):
def __init__(self, hidden_dim=128, input_dim=192+128):
super(SepConvGRU, self).__init__()
self.convz1 = nn.Conv2d(hidden_dim+input_dim, hidden_dim, (1,5), padding=(0,2))
self.convr1 = nn.Conv2d(hidden_dim+input_dim, hidden_dim, (1,5), padding=(0,2))
self.convq1 = nn.Conv2d(hidden_dim+input_dim, hidden_dim, (1,5), padding=(0,2))
self.convz2 = nn.Conv2d(hidden_dim+input_dim, hidden_dim, (5,1), padding=(2,0))
self.convr2 = nn.Conv2d(hidden_dim+input_dim, hidden_dim, (5,1), padding=(2,0))
self.convq2 = nn.Conv2d(hidden_dim+input_dim, hidden_dim, (5,1), padding=(2,0))
def forward(self, h, x):
# horizontal
hx = torch.cat([h, x], dim=1)
z = torch.sigmoid(self.convz1(hx))
r = torch.sigmoid(self.convr1(hx))
q = torch.tanh(self.convq1(torch.cat([r*h, x], dim=1)))
h = (1-z) * h + z * q
# vertical
hx = torch.cat([h, x], dim=1)
z = torch.sigmoid(self.convz2(hx))
r = torch.sigmoid(self.convr2(hx))
q = torch.tanh(self.convq2(torch.cat([r*h, x], dim=1)))
h = (1-z) * h + z * q
return h
class BasicMotionEncoder(nn.Module):
def __init__(self, cor_planes):
super(BasicMotionEncoder, self).__init__()
self.convc1 = nn.Conv2d(cor_planes, 256, 1, padding=0)
self.convc2 = nn.Conv2d(256, 192, 3, padding=1)
self.convf1 = nn.Conv2d(2, 128, 7, padding=3)
self.convf2 = nn.Conv2d(128, 64, 3, padding=1)
self.conv = nn.Conv2d(64+192, 128-2, 3, padding=1)
def forward(self, flow, corr):
cor = F.relu(self.convc1(corr))
cor = F.relu(self.convc2(cor))
flo = F.relu(self.convf1(flow))
flo = F.relu(self.convf2(flo))
cor_flo = torch.cat([cor, flo], dim=1)
out = F.relu(self.conv(cor_flo))
return torch.cat([out, flow], dim=1)
class BasicUpdateBlock(nn.Module):
def __init__(self, hidden_dim, cor_planes, mask_size=8):
super(BasicUpdateBlock, self).__init__()
self.encoder = BasicMotionEncoder(cor_planes)
self.gru = SepConvGRU(hidden_dim=hidden_dim, input_dim=128+hidden_dim)
self.flow_head = FlowHead(hidden_dim, hidden_dim=256)
self.mask = nn.Sequential(
nn.Conv2d(128, 256, 3, padding=1),
nn.ReLU(inplace=True),
nn.Conv2d(256, mask_size**2 *9, 1, padding=0))
def forward(self, net, inp, corr, flow, upsample=True):
# print(inp.shape, corr.shape, flow.shape)
motion_features = self.encoder(flow, corr)
# print(motion_features.shape, inp.shape)
inp = torch.cat((inp, motion_features), dim=1)
net = self.gru(net, inp)
delta_flow = self.flow_head(net)
# scale mask to balence gradients
mask = .25 * self.mask(net)
return net, mask, delta_flow
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