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


class REBNCONV(nn.Module):
    def __init__(self, in_ch=3, out_ch=3, dirate=1):
        super(REBNCONV, self).__init__()

        self.conv_s1 = nn.Conv2d(in_ch, out_ch, 3, padding=1 * dirate, dilation=1 * dirate)
        self.bn_s1 = nn.BatchNorm2d(out_ch)
        self.relu_s1 = nn.ReLU(inplace=True)

    def forward(self, x):
        hx = x
        xout = self.relu_s1(self.bn_s1(self.conv_s1(hx)))

        return xout

# Border Network
class RRB(nn.Module):
    def __init__(self, in_ch, out_ch):
        super(RRB, self).__init__()
        self.conv1 = nn.Conv2d(in_ch, out_ch, kernel_size=1, stride=1, padding=0)
        self.conv2 = nn.Conv2d(out_ch, out_ch, kernel_size=3, stride=1, padding=1)
        self.relu = nn.ReLU()
        self.bn = nn.BatchNorm2d(out_ch)
        self.conv3 = nn.Conv2d(out_ch, out_ch, kernel_size=3, stride=1, padding=1)

    def forward(self, x):
        x = self.conv1(x)
        res = self.conv2(x)
        res = self.bn(res)
        res = self.relu(res)
        res = self.conv3(res)
        return self.relu(x + res)

# CBAM attention
class CBAMLayer(nn.Module):
    def __init__(self, channel, reduction=16, spatial_kernel=7):
        super(CBAMLayer, self).__init__()
        # channel attention 压缩H,W为1
        self.max_pool = nn.AdaptiveMaxPool2d(1)
        self.avg_pool = nn.AdaptiveAvgPool2d(1)
        # shared MLP
        self.mlp = nn.Sequential(
            # Conv2d比Linear方便操作
            # nn.Linear(channel, channel // reduction, bias=False)
            nn.Conv2d(channel, channel // reduction, 1, bias=False),
            # inplace=True直接替换，节省内存
            nn.ReLU(inplace=True),
            # nn.Linear(channel // reduction, channel,bias=False)
            nn.Conv2d(channel // reduction, channel, 1, bias=False)
        )
        # spatial attention
        self.conv = nn.Conv2d(2, 1, kernel_size=spatial_kernel,
                              padding=spatial_kernel // 2, bias=False)
        self.sigmoid = nn.Sigmoid()
    def forward(self, x):
        max_out = self.mlp(self.max_pool(x))
        avg_out = self.mlp(self.avg_pool(x))
        channel_out = self.sigmoid(max_out + avg_out)
        x = channel_out * x
        max_out, _ = torch.max(x, dim=1, keepdim=True)
        avg_out = torch.mean(x, dim=1, keepdim=True)
        spatial_out = self.sigmoid(self.conv(torch.cat([max_out, avg_out], dim=1)))
        x = spatial_out * x
        return x

## upsample tensor 'src' to have the same spatial size with tensor 'tar'
def _upsample_like(src, tar):
    # src = F.upsample(src, size=tar.shape[2:], mode='bilinear') # old version torch
    src = F.upsample(src, size=tar.shape[2:], mode='bilinear', align_corners=True)

    return src


### RSU-7 ###
class RSU7(nn.Module):  # UNet07DRES(nn.Module):

    def __init__(self, in_ch=3, mid_ch=12, out_ch=3):
        super(RSU7, self).__init__()

        self.rebnconvin = REBNCONV(in_ch, out_ch, dirate=1)

        self.rebnconv1 = REBNCONV(out_ch, mid_ch, dirate=1)
        self.pool1 = nn.MaxPool2d(2, stride=2, ceil_mode=True)

        self.rebnconv2 = REBNCONV(mid_ch, mid_ch, dirate=1)
        self.pool2 = nn.MaxPool2d(2, stride=2, ceil_mode=True)

        self.rebnconv3 = REBNCONV(mid_ch, mid_ch, dirate=1)
        self.pool3 = nn.MaxPool2d(2, stride=2, ceil_mode=True)

        self.rebnconv4 = REBNCONV(mid_ch, mid_ch, dirate=1)
        self.pool4 = nn.MaxPool2d(2, stride=2, ceil_mode=True)

        self.rebnconv5 = REBNCONV(mid_ch, mid_ch, dirate=1)
        self.pool5 = nn.MaxPool2d(2, stride=2, ceil_mode=True)

        self.rebnconv6 = REBNCONV(mid_ch, mid_ch, dirate=1)

        self.rebnconv7 = REBNCONV(mid_ch, mid_ch, dirate=2)

        self.rebnconv6d = REBNCONV(mid_ch * 2, mid_ch, dirate=1)
        self.rebnconv5d = REBNCONV(mid_ch * 2, mid_ch, dirate=1)
        self.rebnconv4d = REBNCONV(mid_ch * 2, mid_ch, dirate=1)
        self.rebnconv3d = REBNCONV(mid_ch * 2, mid_ch, dirate=1)
        self.rebnconv2d = REBNCONV(mid_ch * 2, mid_ch, dirate=1)
        self.rebnconv1d = REBNCONV(mid_ch * 2, out_ch, dirate=1)

    def forward(self, x):
        hx = x
        hxin = self.rebnconvin(hx)

        hx1 = self.rebnconv1(hxin)
        hx = self.pool1(hx1)

        hx2 = self.rebnconv2(hx)
        hx = self.pool2(hx2)

        hx3 = self.rebnconv3(hx)
        hx = self.pool3(hx3)

        hx4 = self.rebnconv4(hx)
        hx = self.pool4(hx4)

        hx5 = self.rebnconv5(hx)
        hx = self.pool5(hx5)

        hx6 = self.rebnconv6(hx)

        hx7 = self.rebnconv7(hx6)

        hx6d = self.rebnconv6d(torch.cat((hx7, hx6), 1))
        hx6dup = _upsample_like(hx6d, hx5)

        hx5d = self.rebnconv5d(torch.cat((hx6dup, hx5), 1))
        hx5dup = _upsample_like(hx5d, hx4)

        hx4d = self.rebnconv4d(torch.cat((hx5dup, hx4), 1))
        hx4dup = _upsample_like(hx4d, hx3)

        hx3d = self.rebnconv3d(torch.cat((hx4dup, hx3), 1))
        hx3dup = _upsample_like(hx3d, hx2)

        hx2d = self.rebnconv2d(torch.cat((hx3dup, hx2), 1))
        hx2dup = _upsample_like(hx2d, hx1)

        hx1d = self.rebnconv1d(torch.cat((hx2dup, hx1), 1))

        return hx1d + hxin


### RSU-6 ###
class RSU6(nn.Module):  # UNet06DRES(nn.Module):

    def __init__(self, in_ch=3, mid_ch=12, out_ch=3):
        super(RSU6, self).__init__()

        self.rebnconvin = REBNCONV(in_ch, out_ch, dirate=1)

        self.rebnconv1 = REBNCONV(out_ch, mid_ch, dirate=1)
        self.pool1 = nn.MaxPool2d(2, stride=2, ceil_mode=True)

        self.rebnconv2 = REBNCONV(mid_ch, mid_ch, dirate=1)
        self.pool2 = nn.MaxPool2d(2, stride=2, ceil_mode=True)

        self.rebnconv3 = REBNCONV(mid_ch, mid_ch, dirate=1)
        self.pool3 = nn.MaxPool2d(2, stride=2, ceil_mode=True)

        self.rebnconv4 = REBNCONV(mid_ch, mid_ch, dirate=1)
        self.pool4 = nn.MaxPool2d(2, stride=2, ceil_mode=True)

        self.rebnconv5 = REBNCONV(mid_ch, mid_ch, dirate=1)

        self.rebnconv6 = REBNCONV(mid_ch, mid_ch, dirate=2)

        self.rebnconv5d = REBNCONV(mid_ch * 2, mid_ch, dirate=1)
        self.rebnconv4d = REBNCONV(mid_ch * 2, mid_ch, dirate=1)
        self.rebnconv3d = REBNCONV(mid_ch * 2, mid_ch, dirate=1)
        self.rebnconv2d = REBNCONV(mid_ch * 2, mid_ch, dirate=1)
        self.rebnconv1d = REBNCONV(mid_ch * 2, out_ch, dirate=1)

    def forward(self, x):
        hx = x

        hxin = self.rebnconvin(hx)

        hx1 = self.rebnconv1(hxin)
        hx = self.pool1(hx1)

        hx2 = self.rebnconv2(hx)
        hx = self.pool2(hx2)

        hx3 = self.rebnconv3(hx)
        hx = self.pool3(hx3)

        hx4 = self.rebnconv4(hx)
        hx = self.pool4(hx4)

        hx5 = self.rebnconv5(hx)

        hx6 = self.rebnconv6(hx5)

        hx5d = self.rebnconv5d(torch.cat((hx6, hx5), 1))
        hx5dup = _upsample_like(hx5d, hx4)

        hx4d = self.rebnconv4d(torch.cat((hx5dup, hx4), 1))
        hx4dup = _upsample_like(hx4d, hx3)

        hx3d = self.rebnconv3d(torch.cat((hx4dup, hx3), 1))
        hx3dup = _upsample_like(hx3d, hx2)

        hx2d = self.rebnconv2d(torch.cat((hx3dup, hx2), 1))
        hx2dup = _upsample_like(hx2d, hx1)

        hx1d = self.rebnconv1d(torch.cat((hx2dup, hx1), 1))

        return hx1d + hxin


### RSU-5 ###
class RSU5(nn.Module):  # UNet05DRES(nn.Module):

    def __init__(self, in_ch=3, mid_ch=12, out_ch=3):
        super(RSU5, self).__init__()

        self.rebnconvin = REBNCONV(in_ch, out_ch, dirate=1)

        self.rebnconv1 = REBNCONV(out_ch, mid_ch, dirate=1)
        self.pool1 = nn.MaxPool2d(2, stride=2, ceil_mode=True)

        self.rebnconv2 = REBNCONV(mid_ch, mid_ch, dirate=1)
        self.pool2 = nn.MaxPool2d(2, stride=2, ceil_mode=True)

        self.rebnconv3 = REBNCONV(mid_ch, mid_ch, dirate=1)
        self.pool3 = nn.MaxPool2d(2, stride=2, ceil_mode=True)

        self.rebnconv4 = REBNCONV(mid_ch, mid_ch, dirate=1)

        self.rebnconv5 = REBNCONV(mid_ch, mid_ch, dirate=2)

        self.rebnconv4d = REBNCONV(mid_ch * 2, mid_ch, dirate=1)
        self.rebnconv3d = REBNCONV(mid_ch * 2, mid_ch, dirate=1)
        self.rebnconv2d = REBNCONV(mid_ch * 2, mid_ch, dirate=1)
        self.rebnconv1d = REBNCONV(mid_ch * 2, out_ch, dirate=1)

    def forward(self, x):
        hx = x

        hxin = self.rebnconvin(hx)

        hx1 = self.rebnconv1(hxin)
        hx = self.pool1(hx1)

        hx2 = self.rebnconv2(hx)
        hx = self.pool2(hx2)

        hx3 = self.rebnconv3(hx)
        hx = self.pool3(hx3)

        hx4 = self.rebnconv4(hx)

        hx5 = self.rebnconv5(hx4)

        hx4d = self.rebnconv4d(torch.cat((hx5, hx4), 1))
        hx4dup = _upsample_like(hx4d, hx3)

        hx3d = self.rebnconv3d(torch.cat((hx4dup, hx3), 1))
        hx3dup = _upsample_like(hx3d, hx2)

        hx2d = self.rebnconv2d(torch.cat((hx3dup, hx2), 1))
        hx2dup = _upsample_like(hx2d, hx1)

        hx1d = self.rebnconv1d(torch.cat((hx2dup, hx1), 1))

        return hx1d + hxin


### RSU-4 ###
class RSU4(nn.Module):  # UNet04DRES(nn.Module):

    def __init__(self, in_ch=3, mid_ch=12, out_ch=3):
        super(RSU4, self).__init__()

        self.rebnconvin = REBNCONV(in_ch, out_ch, dirate=1)

        self.rebnconv1 = REBNCONV(out_ch, mid_ch, dirate=1)
        self.pool1 = nn.MaxPool2d(2, stride=2, ceil_mode=True)

        self.rebnconv2 = REBNCONV(mid_ch, mid_ch, dirate=1)
        self.pool2 = nn.MaxPool2d(2, stride=2, ceil_mode=True)

        self.rebnconv3 = REBNCONV(mid_ch, mid_ch, dirate=1)

        self.rebnconv4 = REBNCONV(mid_ch, mid_ch, dirate=2)

        self.rebnconv3d = REBNCONV(mid_ch * 2, mid_ch, dirate=1)
        self.rebnconv2d = REBNCONV(mid_ch * 2, mid_ch, dirate=1)
        self.rebnconv1d = REBNCONV(mid_ch * 2, out_ch, dirate=1)

    def forward(self, x):
        hx = x

        hxin = self.rebnconvin(hx)

        hx1 = self.rebnconv1(hxin)
        hx = self.pool1(hx1)

        hx2 = self.rebnconv2(hx)
        hx = self.pool2(hx2)

        hx3 = self.rebnconv3(hx)

        hx4 = self.rebnconv4(hx3)

        hx3d = self.rebnconv3d(torch.cat((hx4, hx3), 1))
        hx3dup = _upsample_like(hx3d, hx2)

        hx2d = self.rebnconv2d(torch.cat((hx3dup, hx2), 1))
        hx2dup = _upsample_like(hx2d, hx1)

        hx1d = self.rebnconv1d(torch.cat((hx2dup, hx1), 1))

        return hx1d + hxin


### RSU-4F ###
class RSU4F(nn.Module):  # UNet04FRES(nn.Module):

    def __init__(self, in_ch=3, mid_ch=12, out_ch=3):
        super(RSU4F, self).__init__()

        self.rebnconvin = REBNCONV(in_ch, out_ch, dirate=1)

        self.rebnconv1 = REBNCONV(out_ch, mid_ch, dirate=1)
        self.rebnconv2 = REBNCONV(mid_ch, mid_ch, dirate=2)
        self.rebnconv3 = REBNCONV(mid_ch, mid_ch, dirate=4)

        self.rebnconv4 = REBNCONV(mid_ch, mid_ch, dirate=8)

        self.rebnconv3d = REBNCONV(mid_ch * 2, mid_ch, dirate=4)
        self.rebnconv2d = REBNCONV(mid_ch * 2, mid_ch, dirate=2)
        self.rebnconv1d = REBNCONV(mid_ch * 2, out_ch, dirate=1)

    def forward(self, x):
        hx = x

        hxin = self.rebnconvin(hx)

        hx1 = self.rebnconv1(hxin)
        hx2 = self.rebnconv2(hx1)
        hx3 = self.rebnconv3(hx2)

        hx4 = self.rebnconv4(hx3)

        hx3d = self.rebnconv3d(torch.cat((hx4, hx3), 1))
        hx2d = self.rebnconv2d(torch.cat((hx3d, hx2), 1))
        hx1d = self.rebnconv1d(torch.cat((hx2d, hx1), 1))

        return hx1d + hxin


##### U^2-Net ####
class U2NET(nn.Module):

    def __init__(self, in_ch=3, out_ch=1):
        super(U2NET, self).__init__()

        self.stage1 = RSU7(in_ch, 32, 64)
        self.pool12 = nn.MaxPool2d(2, stride=2, ceil_mode=True)

        self.stage2 = RSU6(64, 32, 128)
        self.pool23 = nn.MaxPool2d(2, stride=2, ceil_mode=True)

        self.stage3 = RSU5(128, 64, 256)
        self.pool34 = nn.MaxPool2d(2, stride=2, ceil_mode=True)

        self.stage4 = RSU4(256, 128, 512)
        self.pool45 = nn.MaxPool2d(2, stride=2, ceil_mode=True)

        self.stage5 = RSU4F(512, 256, 512)
        self.pool56 = nn.MaxPool2d(2, stride=2, ceil_mode=True)

        self.stage6 = RSU4F(512, 256, 512)

        ##################
        self.upsample = nn.Upsample(scale_factor=2, mode="bilinear")
        self.upsample_4 = nn.Upsample(scale_factor=4, mode="bilinear")
        self.upsample_8 = nn.Upsample(scale_factor=8, mode="bilinear")
        self.upsample_16 = nn.Upsample(scale_factor=16, mode="bilinear")
        self.upsample_32 = nn.Upsample(scale_factor=32, mode="bilinear")

        self.rrb_db_1 = RRB(64, 1)
        self.rrb_db_2 = RRB(128, 1)
        self.rrb_db_3 = RRB(256, 1)
        self.rrb_db_4 = RRB(512, 1)
        self.rrb_db_5 = RRB(512, 1)
        self.rrb_db_6 = RRB(512, 1)

        self.rrb_trans_1 = RRB(1,1)
        self.rrb_trans_2 = RRB(1,1)
        self.rrb_trans_3 = RRB(1,1)
        self.rrb_trans_4 = RRB(1,1)
        self.rrb_trans_5 = RRB(1,1)

        #################################################

        # CBAM attention
        self.sa1 = CBAMLayer(64)
        self.sa2 = CBAMLayer(128)
        self.sa3 = CBAMLayer(256)
        self.sa4 = CBAMLayer(512)
        self.sa5 = CBAMLayer(512)

        ############################################################

        # decoder
        self.stage5d = RSU4F(1024, 256, 512)
        self.stage4d = RSU4(1024, 128, 256)
        self.stage3d = RSU5(512, 64, 128)
        self.stage2d = RSU6(256, 32, 64)
        self.stage1d = RSU7(128, 16, 64)

        self.side1 = nn.Conv2d(64, out_ch, 3, padding=1)
        self.side2 = nn.Conv2d(64, out_ch, 3, padding=1)
        self.side3 = nn.Conv2d(128, out_ch, 3, padding=1)
        self.side4 = nn.Conv2d(256, out_ch, 3, padding=1)
        self.side5 = nn.Conv2d(512, out_ch, 3, padding=1)
        self.side6 = nn.Conv2d(512, out_ch, 3, padding=1)
        self.side7 = nn.Conv2d(1, out_ch, 3, padding=1)

        self.outconv = nn.Conv2d(7 * out_ch, out_ch, 1)

    def forward(self, x):
        hx = x

        # stage 1
        hx1 = self.stage1(hx)
        hx = self.pool12(hx1)

        # stage 2
        hx2 = self.stage2(hx)
        hx = self.pool23(hx2)

        # stage 3
        hx3 = self.stage3(hx)
        hx = self.pool34(hx3)

        # stage 4
        hx4 = self.stage4(hx)
        hx = self.pool45(hx4)

        # stage 5
        hx5 = self.stage5(hx)
        hx = self.pool56(hx5)

        # stage 6
        hx6 = self.stage6(hx)
        hx6up = _upsample_like(hx6, hx5)

        res1 = self.rrb_db_1(hx1)
        res1 = self.rrb_trans_1(res1 + self.upsample(self.rrb_db_2(hx2)))
        res1 = self.rrb_trans_2(res1 + self.upsample_4(self.rrb_db_3(hx3)))
        res1 = self.rrb_trans_3(res1 + self.upsample_8(self.rrb_db_4(hx4)))
        res1 = self.rrb_trans_4(res1 + self.upsample_16(self.rrb_db_5(hx5)))
        res1 = self.rrb_trans_5(res1 + self.upsample_32(self.rrb_db_6(hx6)))

        # -------------------- decoder --------------------
        sa5 = self.sa5(hx5)
        hx5d = self.stage5d(torch.cat((hx6up, sa5), 1))
        hx5dup = _upsample_like(hx5d, hx4)

        sa4 = self.sa4(hx4)
        hx4d = self.stage4d(torch.cat((hx5dup, sa4), 1))
        hx4dup = _upsample_like(hx4d, hx3)

        sa3 = self.sa3(hx3)
        hx3d = self.stage3d(torch.cat((hx4dup, sa3), 1))
        hx3dup = _upsample_like(hx3d, hx2)

        sa2 = self.sa2(hx2)
        hx2d = self.stage2d(torch.cat((hx3dup, sa2), 1))
        hx2dup = _upsample_like(hx2d, hx1)

        sa1 = self.sa1(hx1)
        hx1d = self.stage1d(torch.cat((hx2dup, sa1), 1))

        # side output
        d1 = self.side1(hx1d)

        d2 = self.side2(hx2d)
        d2 = _upsample_like(d2, d1)

        d3 = self.side3(hx3d)
        d3 = _upsample_like(d3, d1)

        d4 = self.side4(hx4d)
        d4 = _upsample_like(d4, d1)

        d5 = self.side5(hx5d)
        d5 = _upsample_like(d5, d1)

        d6 = self.side6(hx6)
        d6 = _upsample_like(d6, d1)

        d7 = self.side7(res1)
        d7 = _upsample_like(d7, d1)

        d0 = self.outconv(torch.cat((d1, d2, d3, d4, d5, d6, d7), 1))

        # return F.sigmoid(d0), F.sigmoid(d1), F.sigmoid(d2), F.sigmoid(d3), F.sigmoid(d4), F.sigmoid(d5), F.sigmoid(d6), F.sigmoid(d7)

        return torch.sigmoid(d0), torch.sigmoid(d1), torch.sigmoid(d2), torch.sigmoid(d3), torch.sigmoid(d4), torch.sigmoid(d5), torch.sigmoid(d6), torch.sigmoid(d7)


### U^2-Net small ###
class U2NETP(nn.Module):

    def __init__(self, in_ch=3, out_ch=1):
        super(U2NETP, self).__init__()

        self.stage1 = RSU7(in_ch, 16, 64)
        self.pool12 = nn.MaxPool2d(2, stride=2, ceil_mode=True)

        self.stage2 = RSU6(64, 16, 64)
        self.pool23 = nn.MaxPool2d(2, stride=2, ceil_mode=True)

        self.stage3 = RSU5(64, 16, 64)
        self.pool34 = nn.MaxPool2d(2, stride=2, ceil_mode=True)

        self.stage4 = RSU4(64, 16, 64)
        self.pool45 = nn.MaxPool2d(2, stride=2, ceil_mode=True)

        self.stage5 = RSU4F(64, 16, 64)
        self.pool56 = nn.MaxPool2d(2, stride=2, ceil_mode=True)

        self.stage6 = RSU4F(64, 16, 64)


        ##################
        self.upsample = nn.Upsample(scale_factor=2, mode="bilinear")
        self.upsample_4 = nn.Upsample(scale_factor=4, mode="bilinear")
        self.upsample_8 = nn.Upsample(scale_factor=8, mode="bilinear")
        self.upsample_16 = nn.Upsample(scale_factor=16, mode="bilinear")
        self.upsample_32 = nn.Upsample(scale_factor=32, mode="bilinear")

        self.rrb_db_1 = RRB(64, 1)
        self.rrb_db_2 = RRB(64, 1)
        self.rrb_db_3 = RRB(64, 1)
        self.rrb_db_4 = RRB(64, 1)
        self.rrb_db_5 = RRB(64, 1)
        self.rrb_db_6 = RRB(64, 1)

        self.rrb_trans_1 = RRB(1,1)
        self.rrb_trans_2 = RRB(1,1)
        self.rrb_trans_3 = RRB(1,1)
        self.rrb_trans_4 = RRB(1,1)
        self.rrb_trans_5 = RRB(1,1)

        #################################################

        # CBAM attention
        self.sa1 = CBAMLayer(64)
        self.sa2 = CBAMLayer(64)
        self.sa3 = CBAMLayer(64)
        self.sa4 = CBAMLayer(64)
        self.sa5 = CBAMLayer(64)
        #####################################################

        # decoder
        self.stage5d = RSU4F(128, 16, 64)
        self.stage4d = RSU4(128, 16, 64)
        self.stage3d = RSU5(128, 16, 64)
        self.stage2d = RSU6(128, 16, 64)
        self.stage1d = RSU7(128, 16, 64)

        self.side1 = nn.Conv2d(64, out_ch, 3, padding=1)
        self.side2 = nn.Conv2d(64, out_ch, 3, padding=1)
        self.side3 = nn.Conv2d(64, out_ch, 3, padding=1)
        self.side4 = nn.Conv2d(64, out_ch, 3, padding=1)
        self.side5 = nn.Conv2d(64, out_ch, 3, padding=1)
        self.side6 = nn.Conv2d(64, out_ch, 3, padding=1)
        self.side7 = nn.Conv2d(1, out_ch, 3, padding=1)

        self.outconv = nn.Conv2d(7 * out_ch, out_ch, 1)

    def forward(self, x):
        hx = x

        # stage 1
        hx1 = self.stage1(hx)
        hx = self.pool12(hx1)

        # stage 2
        hx2 = self.stage2(hx)
        hx = self.pool23(hx2)

        # stage 3
        hx3 = self.stage3(hx)
        hx = self.pool34(hx3)

        # stage 4
        hx4 = self.stage4(hx)
        hx = self.pool45(hx4)

        # stage 5
        hx5 = self.stage5(hx)
        hx = self.pool56(hx5)

        # stage 6
        hx6 = self.stage6(hx)
        hx6up = _upsample_like(hx6, hx5)

        res1 = self.rrb_db_1(hx1)
        res1 = self.rrb_trans_1(res1 + self.upsample(self.rrb_db_2(hx2)))
        res1 = self.rrb_trans_2(res1 + self.upsample_4(self.rrb_db_3(hx3)))
        res1 = self.rrb_trans_3(res1 + self.upsample_8(self.rrb_db_4(hx4)))
        res1 = self.rrb_trans_4(res1 + self.upsample_16(self.rrb_db_5(hx5)))
        res1 = self.rrb_trans_5(res1 + self.upsample_32(self.rrb_db_6(hx6)))

        # decoder
        sa5 = self.sa5(hx5)
        hx5d = self.stage5d(torch.cat((hx6up, sa5), 1))
        hx5dup = _upsample_like(hx5d, hx4)

        sa4 = self.sa4(hx4)
        hx4d = self.stage4d(torch.cat((hx5dup, sa4), 1))
        hx4dup = _upsample_like(hx4d, hx3)

        sa3 = self.sa3(hx3)
        hx3d = self.stage3d(torch.cat((hx4dup, sa3), 1))
        hx3dup = _upsample_like(hx3d, hx2)

        sa2 = self.sa2(hx2)
        hx2d = self.stage2d(torch.cat((hx3dup, sa2), 1))
        hx2dup = _upsample_like(hx2d, hx1)

        sa1 = self.sa1(hx1)
        hx1d = self.stage1d(torch.cat((hx2dup, sa1), 1))

        # side output
        d1 = self.side1(hx1d)

        d2 = self.side2(hx2d)
        d2 = _upsample_like(d2, d1)

        d3 = self.side3(hx3d)
        d3 = _upsample_like(d3, d1)

        d4 = self.side4(hx4d)
        d4 = _upsample_like(d4, d1)

        d5 = self.side5(hx5d)
        d5 = _upsample_like(d5, d1)

        d6 = self.side6(hx6)
        d6 = _upsample_like(d6, d1)

        d7 = self.side7(res1)
        d7 = _upsample_like(d7, d1)

        d0 = self.outconv(torch.cat((d1, d2, d3, d4, d5, d6, d7), 1))

        # return F.sigmoid(d0), F.sigmoid(d1), F.sigmoid(d2), F.sigmoid(d3), F.sigmoid(d4), F.sigmoid(d5), F.sigmoid(d6), F.sigmoid(d7)
        return torch.sigmoid(d0), torch.sigmoid(d1), torch.sigmoid(d2), torch.sigmoid(d3), torch.sigmoid(d4), torch.sigmoid(d5), torch.sigmoid(d6), torch.sigmoid(d7)