def forward(self, fmap1, fmap2, coords):
self.corr_pyramid = []
corr = self.compute_cost_volume(fmap1, fmap2)
batch, h1, w1, dim, h2, w2 = corr.shape
corr = corr.view(batch*h1*w1, dim, h2, w2)
self.corr_pyramid.append(corr)
for i in range(self.num_levels):
corr = F.avg_pool2d(corr, 2, stride=2)
self.corr_pyramid.append(corr)
r = self.radius
coords = coords.permute(0, 2, 3, 1)
batch, h1, w1, _ = coords.shape
out_pyramid = []
for i in range(self.num_levels):
corr = self.corr_pyramid[i]
dx = torch.linspace(-r, r, 2*r+1)
dy = torch.linspace(-r, r, 2*r+1)
delta = torch.stack(torch.meshgrid(dy, dx), axis=-1).to(coords.device)
centroid_lvl = coords.reshape(batch*h1*w1, 1, 1, 2) / 2**i
delta_lvl = delta.view(1, 2*r+1, 2*r+1, 2)
coords_lvl = centroid_lvl + delta_lvl
corr = bilinear_sampler(corr, coords_lvl)
corr = corr.view(batch, h1, w1, -1)
out_pyramid.append(corr)
out = torch.cat(out_pyramid, dim=-1)
return out.permute(0, 3, 1, 2)
def __call__(self, coords):
r = self.radius
coords = coords.permute(0, 2, 3, 1)
batch, h1, w1, _ = coords.shape
out_pyramid = []
for i in range(self.num_levels):
corr = self.corr_pyramid[i]
dx = torch.linspace(-r, r, 2*r+1)
dy = torch.linspace(-r, r, 2*r+1)
delta = torch.stack(torch.meshgrid(dy, dx), axis=-1).to(coords.device)
centroid_lvl = coords.reshape(batch*h1*w1, 1, 1, 2) / 2**i
delta_lvl = delta.view(1, 2*r+1, 2*r+1, 2)
coords_lvl = centroid_lvl + delta_lvl
corr = bilinear_sampler(corr, coords_lvl)
corr = corr.view(batch, h1, w1, -1)
out_pyramid.append(corr)
out = torch.cat(out_pyramid, dim=-1)
return out.permute(0, 3, 1, 2).contiguous().float()