File size: 1,283 Bytes
b13b124 |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 |
import torch
from ..builder import HEADS
from .fcn_head import FCNHead
try:
from mmcv.ops import CrissCrossAttention
except ModuleNotFoundError:
CrissCrossAttention = None
@HEADS.register_module()
class CCHead(FCNHead):
"""CCNet: Criss-Cross Attention for Semantic Segmentation.
This head is the implementation of `CCNet
<https://arxiv.org/abs/1811.11721>`_.
Args:
recurrence (int): Number of recurrence of Criss Cross Attention
module. Default: 2.
"""
def __init__(self, recurrence=2, **kwargs):
if CrissCrossAttention is None:
raise RuntimeError('Please install mmcv-full for '
'CrissCrossAttention ops')
super(CCHead, self).__init__(num_convs=2, **kwargs)
self.recurrence = recurrence
self.cca = CrissCrossAttention(self.channels)
def forward(self, inputs):
"""Forward function."""
x = self._transform_inputs(inputs)
output = self.convs[0](x)
for _ in range(self.recurrence):
output = self.cca(output)
output = self.convs[1](output)
if self.concat_input:
output = self.conv_cat(torch.cat([x, output], dim=1))
output = self.cls_seg(output)
return output
|