init

lib/models/heads/uper_head.py

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+# coding: utf-8
+# Copyright (c) Ant Group. All rights reserved.
+import torch
+import torch.nn as nn
+import torch.nn.functional as F
+from mmcv.cnn import ConvModule
+
+from mmseg.ops import resize
+from mmseg.models.decode_heads.decode_head import BaseDecodeHead
+from .psp_head import PPM
+
+
+class UPerHead(BaseDecodeHead):
+    """Unified Perceptual Parsing for Scene Understanding.
+
+    This head is the implementation of `UPerNet
+    <https://arxiv.org/abs/1807.10221>`_.
+
+    Args:
+        pool_scales (tuple[int]): Pooling scales used in Pooling Pyramid
+            Module applied on the last feature. Default: (1, 2, 3, 6).
+    """
+
+    def __init__(self, pool_scales=(1, 2, 3, 6), **kwargs):
+        super(UPerHead, self).__init__(
+            input_transform='multiple_select', **kwargs)
+        # PSP Module
+        self.psp_modules = PPM(
+            pool_scales,
+            self.in_channels[-1],
+            self.channels,
+            conv_cfg=self.conv_cfg,
+            norm_cfg=self.norm_cfg,
+            act_cfg=self.act_cfg,
+            align_corners=self.align_corners)
+        self.bottleneck = ConvModule(
+            self.in_channels[-1] + len(pool_scales) * self.channels,
+            self.channels,
+            3,
+            padding=1,
+            conv_cfg=self.conv_cfg,
+            norm_cfg=self.norm_cfg,
+            act_cfg=self.act_cfg)
+        # FPN Module
+        self.lateral_convs = nn.ModuleList()
+        self.fpn_convs = nn.ModuleList()
+        for in_channels in self.in_channels[:-1]:  # skip the top layer
+            l_conv = ConvModule(
+                in_channels,
+                self.channels,
+                1,
+                conv_cfg=self.conv_cfg,
+                norm_cfg=self.norm_cfg,
+                act_cfg=self.act_cfg,
+                inplace=False)
+            fpn_conv = ConvModule(
+                self.channels,
+                self.channels,
+                3,
+                padding=1,
+                conv_cfg=self.conv_cfg,
+                norm_cfg=self.norm_cfg,
+                act_cfg=self.act_cfg,
+                inplace=False)
+            self.lateral_convs.append(l_conv)
+            self.fpn_convs.append(fpn_conv)
+
+        self.fpn_bottleneck = ConvModule(
+            len(self.in_channels) * self.channels,
+            self.channels,
+            3,
+            padding=1,
+            conv_cfg=self.conv_cfg,
+            norm_cfg=self.norm_cfg,
+            act_cfg=self.act_cfg)
+
+    def psp_forward(self, inputs):
+        """Forward function of PSP module."""
+        x = inputs[-1]
+        psp_outs = [x]
+        # breakpoint()
+        psp_outs.extend(self.psp_modules(x))
+        psp_outs = torch.cat(psp_outs, dim=1)
+        output = self.bottleneck(psp_outs)
+
+        return output
+
+    def forward(self, inputs):
+        """Forward function."""
+        # breakpoint()
+        inputs = self._transform_inputs(inputs)
+
+        # build laterals
+        laterals = [
+            lateral_conv(inputs[i])
+            for i, lateral_conv in enumerate(self.lateral_convs)
+        ]
+
+        laterals.append(self.psp_forward(inputs))
+
+        # build top-down path
+        used_backbone_levels = len(laterals)
+        for i in range(used_backbone_levels - 1, 0, -1):
+            prev_shape = laterals[i - 1].shape[2:]
+            laterals[i] = laterals[i].type(torch.float32)
+            laterals[i - 1] = laterals[i - 1] + resize(
+                laterals[i],
+                size=prev_shape,
+                mode='bilinear',
+                align_corners=self.align_corners)
+
+        # build outputs
+        fpn_outs = [
+            self.fpn_convs[i](laterals[i])
+            for i in range(used_backbone_levels - 1)
+        ]
+        # append psp feature
+        fpn_outs.append(laterals[-1])
+
+        for i in range(used_backbone_levels - 1, 0, -1):
+            fpn_outs[i] = fpn_outs[i].type(torch.float32)
+            fpn_outs[i] = resize(
+                fpn_outs[i],
+                size=fpn_outs[0].shape[2:],
+                mode='bilinear',
+                align_corners=self.align_corners)
+        fpn_outs = torch.cat(fpn_outs, dim=1)
+        output = self.fpn_bottleneck(fpn_outs)
+        output = self.cls_seg(output)
+        return output