import torch
import torch.nn as nn
import torch.nn.functional as F
from nnutils import make_conv_2d, make_upscale_2d, make_downscale_2d, ResBlock2d, Identity
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):
x = self.relu(self.conv1(x))
return self.conv2(x), x
class ConvGRU(nn.Module):
def __init__(self, hidden_dim=128, input_dim=192+128):
super(ConvGRU, self).__init__()
self.convz = nn.Conv2d(hidden_dim+input_dim, hidden_dim, 3, padding=1)
self.convr = nn.Conv2d(hidden_dim+input_dim, hidden_dim, 3, padding=1)
self.convq = nn.Conv2d(hidden_dim+input_dim, hidden_dim, 3, padding=1)
def forward(self, h, x):
hx = torch.cat([h, x], dim=1)
z = torch.sigmoid(self.convz(hx))
r = torch.sigmoid(self.convr(hx))
q = torch.tanh(self.convq(torch.cat([r*h, x], dim=1)))
h = (1-z) * h + z * q
return h
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 SmallMotionEncoder(nn.Module):
def __init__(self, args):
super(SmallMotionEncoder, self).__init__()
cor_planes = args.corr_levels * (2*args.corr_radius + 1)**2
self.convc1 = nn.Conv2d(cor_planes, 96, 1, padding=0)
self.convf1 = nn.Conv2d(2, 64, 7, padding=3)
self.convf2 = nn.Conv2d(64, 32, 3, padding=1)
self.conv = nn.Conv2d(128, 80, 3, padding=1)
def forward(self, flow, corr):
cor = F.relu(self.convc1(corr))
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 BasicMotionEncoder(nn.Module):
def __init__(self, args):
super(BasicMotionEncoder, self).__init__()
cor_planes = args.corr_levels * (2*args.corr_radius + 1)**2
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 SmallUpdateBlock(nn.Module):
def __init__(self, args, hidden_dim=96):
super(SmallUpdateBlock, self).__init__()
self.encoder = SmallMotionEncoder(args)
self.gru = ConvGRU(hidden_dim=hidden_dim, input_dim=82+64)
self.flow_head = FlowHead(hidden_dim, hidden_dim=128)
def forward(self, net, inp, corr, flow):
motion_features = self.encoder(flow, corr)
inp = torch.cat([inp, motion_features], dim=1)
net = self.gru(net, inp)
delta_flow, feature = self.flow_head(net)
return net, None, delta_flow, feature
class BasicUpdateBlock(nn.Module):
def __init__(self, args, hidden_dim=128, input_dim=128):
super(BasicUpdateBlock, self).__init__()
self.args = args
self.encoder = BasicMotionEncoder(args)
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, 64*9, 1, padding=0))
def forward(self, net, inp, corr, flow, upsample=True):
motion_features = self.encoder(flow, corr)
inp = torch.cat([inp, motion_features], dim=1)
net = self.gru(net, inp)
delta_flow, feature = self.flow_head(net)
# scale mask to balence gradients
mask = .25 * self.mask(net)
return net, mask, delta_flow, feature
class BasicWeightsNet(nn.Module):
def __init__(self, opt):
super(BasicUpdateBlock, self).__init__()
if opt.small:
in_dim = 128
else:
in_dim = 256
fn_0 = 16
self.input_fn = fn_0 + 2
fn_1 = 16
self.conv1 = torch.nn.Conv2d(in_channels=in_dim, out_channels=fn_0, kernel_size=3, stride=1, padding=1)
if opt.use_batch_norm:
custom_batch_norm = torch.nn.BatchNorm2d
else:
custom_batch_norm = Identity
self.model = nn.Sequential(
make_conv_2d(self.input_fn, fn_1, n_blocks=1, normalization=custom_batch_norm),
ResBlock2d(fn_1, normalization=custom_batch_norm),
ResBlock2d(fn_1, normalization=custom_batch_norm),
ResBlock2d(fn_1, normalization=custom_batch_norm),
nn.Conv2d(fn_1, 1, kernel_size=3, padding=1),
torch.nn.Sigmoid()
)
def forward(self, flow, feature):
features = self.conv1(features)
x = torch.cat([features, flow], 1)
return self.model(x)