models/vr_arch/layers.py

import torch
from torch import nn
import torch.nn.functional as F

from . import spec_utils


class Conv2DBNActiv(nn.Module):

    def __init__(self, nin, nout, ksize=3, stride=1, pad=1, dilation=1, activ=nn.ReLU):
        super(Conv2DBNActiv, self).__init__()

        self.conv = nn.Sequential(
            nn.Conv2d(
                nin,
                nout,
                kernel_size=ksize,
                stride=stride,
                padding=pad,
                dilation=dilation,
                bias=False,
            ),
            nn.BatchNorm2d(nout),
            activ(),
        )

    def __call__(self, input_tensor):
        return self.conv(input_tensor)


class SeperableConv2DBNActiv(nn.Module):

    def __init__(self, nin, nout, ksize=3, stride=1, pad=1, dilation=1, activ=nn.ReLU):
        super(SeperableConv2DBNActiv, self).__init__()

        self.conv = nn.Sequential(
            nn.Conv2d(
                nin,
                nin,
                kernel_size=ksize,
                stride=stride,
                padding=pad,
                dilation=dilation,
                groups=nin,
                bias=False,
            ),
            nn.Conv2d(
                nin,
                nout,
                kernel_size=1,
                bias=False,
            ),
            nn.BatchNorm2d(nout),
            activ(),
        )

    def __call__(self, input_tensor):
        return self.conv(input_tensor)


class Encoder(nn.Module):

    def __init__(self, nin, nout, ksize=3, stride=1, pad=1, activ=nn.LeakyReLU):
        super(Encoder, self).__init__()

        self.conv1 = Conv2DBNActiv(nin, nout, ksize, 1, pad, activ=activ)

        self.conv2 = Conv2DBNActiv(nout, nout, ksize, stride, pad, activ=activ)

    def __call__(self, input_tensor):
        skip = self.conv1(input_tensor)

        hidden = self.conv2(skip)

        return hidden, skip


class Decoder(nn.Module):

    def __init__(
        self, nin, nout, ksize=3, stride=1, pad=1, activ=nn.ReLU, dropout=False
    ):
        super(Decoder, self).__init__()

        self.conv = Conv2DBNActiv(nin, nout, ksize, 1, pad, activ=activ)

        self.dropout = nn.Dropout2d(0.1) if dropout else None

    def __call__(self, input_tensor, skip=None):
        input_tensor = F.interpolate(
            input_tensor, scale_factor=2, mode="bilinear", align_corners=True
        )
        if skip is not None:
            skip = spec_utils.crop_center(skip, input_tensor)
            input_tensor = torch.cat([input_tensor, skip], dim=1)

        output_tensor = self.conv(input_tensor)

        if self.dropout is not None:
            output_tensor = self.dropout(output_tensor)

        return output_tensor


class ASPPModule(nn.Module):

    def __init__(self, nn_architecture, nin, nout, dilations=(4, 8, 16), activ=nn.ReLU):
        super(ASPPModule, self).__init__()

        self.conv1 = nn.Sequential(
            nn.AdaptiveAvgPool2d((1, None)),
            Conv2DBNActiv(nin, nin, 1, 1, 0, activ=activ),
        )

        self.nn_architecture = nn_architecture
        self.six_layer = [129605]
        self.seven_layer = [537238, 537227, 33966]

        extra_conv = SeperableConv2DBNActiv(
            nin, nin, 3, 1, dilations[2], dilations[2], activ=activ
        )

        self.conv2 = Conv2DBNActiv(nin, nin, 1, 1, 0, activ=activ)

        self.conv3 = SeperableConv2DBNActiv(
            nin, nin, 3, 1, dilations[0], dilations[0], activ=activ
        )
        self.conv4 = SeperableConv2DBNActiv(
            nin, nin, 3, 1, dilations[1], dilations[1], activ=activ
        )
        self.conv5 = SeperableConv2DBNActiv(
            nin, nin, 3, 1, dilations[2], dilations[2], activ=activ
        )

        if self.nn_architecture in self.six_layer:
            self.conv6 = extra_conv
            nin_x = 6
        elif self.nn_architecture in self.seven_layer:
            self.conv6 = extra_conv
            self.conv7 = extra_conv
            nin_x = 7
        else:
            nin_x = 5

        self.bottleneck = nn.Sequential(
            Conv2DBNActiv(nin * nin_x, nout, 1, 1, 0, activ=activ), nn.Dropout2d(0.1)
        )

    def forward(self, input_tensor):
        _, _, h, w = input_tensor.size()

        feat1 = F.interpolate(
            self.conv1(input_tensor), size=(h, w), mode="bilinear", align_corners=True
        )

        feat2 = self.conv2(input_tensor)
        feat3 = self.conv3(input_tensor)
        feat4 = self.conv4(input_tensor)
        feat5 = self.conv5(input_tensor)

        if self.nn_architecture in self.six_layer:
            feat6 = self.conv6(input_tensor)
            out = torch.cat((feat1, feat2, feat3, feat4, feat5, feat6), dim=1)
        elif self.nn_architecture in self.seven_layer:
            feat6 = self.conv6(input_tensor)
            feat7 = self.conv7(input_tensor)
            out = torch.cat((feat1, feat2, feat3, feat4, feat5, feat6, feat7), dim=1)
        else:
            out = torch.cat((feat1, feat2, feat3, feat4, feat5), dim=1)

        bottleneck_output = self.bottleneck(out)
        return bottleneck_output