Create SRMNet.py

model_arch/SRMNet.py

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+import torch
+import torch.nn as nn
+
+##---------- Basic Layers ----------
+def conv3x3(in_chn, out_chn, bias=True):
+    layer = nn.Conv2d(in_chn, out_chn, kernel_size=3, stride=1, padding=1, bias=bias)
+    return layer
+
+def conv(in_channels, out_channels, kernel_size, bias=False, stride=1):
+    return nn.Conv2d(
+        in_channels, out_channels, kernel_size,
+        padding=(kernel_size // 2), bias=bias, stride=stride)
+
+def bili_resize(factor):
+    return nn.Upsample(scale_factor=factor, mode='bilinear', align_corners=False)
+
+##---------- Basic Blocks ----------
+
+class UNetConvBlock(nn.Module):
+    def __init__(self, in_size, out_size, downsample):
+        super(UNetConvBlock, self).__init__()
+        self.downsample = downsample
+        self.block = SK_RDB(in_channels=in_size, growth_rate=out_size, num_layers=3)
+        if downsample:
+            self.downsample = PS_down(out_size, out_size, downscale=2)
+
+    def forward(self, x):
+        out = self.block(x)
+        if self.downsample:
+            out_down = self.downsample(out)
+            return out_down, out
+        else:
+            return out
+
+class UNetUpBlock(nn.Module):
+    def __init__(self, in_size, out_size):
+        super(UNetUpBlock, self).__init__()
+        # self.up = nn.ConvTranspose2d(in_size, out_size, kernel_size=2, stride=2, bias=True)
+        self.up = PS_up(in_size, out_size, upscale=2)
+        self.conv_block = UNetConvBlock(in_size, out_size, False)
+
+    def forward(self, x, bridge):
+        up = self.up(x)
+        out = torch.cat([up, bridge], dim=1)
+        out = self.conv_block(out)
+        return out
+
+##---------- Resizing Modules (Pixel(Un)Shuffle) ----------
+class PS_down(nn.Module):
+    def __init__(self, in_size, out_size, downscale):
+        super(PS_down, self).__init__()
+        self.UnPS = nn.PixelUnshuffle(downscale)
+        self.conv1 = nn.Conv2d((downscale**2) * in_size, out_size, 1, 1, 0)
+
+    def forward(self, x):
+        x = self.UnPS(x)  # h/2, w/2, 4*c
+        x = self.conv1(x)
+        return x
+
+class PS_up(nn.Module):
+    def __init__(self, in_size, out_size, upscale):
+        super(PS_up, self).__init__()
+
+        self.PS = nn.PixelShuffle(upscale)
+        self.conv1 = nn.Conv2d(in_size//(upscale**2), out_size, 1, 1, 0)
+
+    def forward(self, x):
+        x = self.PS(x)  # h/2, w/2, 4*c
+        x = self.conv1(x)
+        return x
+
+##---------- Selective Kernel Feature Fusion (SKFF) ----------
+class SKFF(nn.Module):
+    def __init__(self, in_channels, height=3, reduction=8, bias=False):
+        super(SKFF, self).__init__()
+
+        self.height = height
+        d = max(int(in_channels / reduction), 4)
+
+        self.avg_pool = nn.AdaptiveAvgPool2d(1)
+        self.conv_du = nn.Sequential(nn.Conv2d(in_channels, d, 1, padding=0, bias=bias), nn.PReLU())
+
+        self.fcs = nn.ModuleList([])
+        for i in range(self.height):
+            self.fcs.append(nn.Conv2d(d, in_channels, kernel_size=1, stride=1, bias=bias))
+
+        self.softmax = nn.Softmax(dim=1)
+
+    def forward(self, inp_feats):
+        batch_size, n_feats, H, W = inp_feats[1].shape
+
+        inp_feats = torch.cat(inp_feats, dim=1)
+        inp_feats = inp_feats.view(batch_size, self.height, n_feats, inp_feats.shape[2], inp_feats.shape[3])
+
+        feats_U = torch.sum(inp_feats, dim=1)
+        feats_S = self.avg_pool(feats_U)
+        feats_Z = self.conv_du(feats_S)
+
+        attention_vectors = [fc(feats_Z) for fc in self.fcs]
+        attention_vectors = torch.cat(attention_vectors, dim=1)
+        attention_vectors = attention_vectors.view(batch_size, self.height, n_feats, 1, 1)
+
+        attention_vectors = self.softmax(attention_vectors)
+        feats_V = torch.sum(inp_feats * attention_vectors, dim=1)
+
+        return feats_V
+
+##---------- Dense Block ----------
+class DenseLayer(nn.Module):
+    def __init__(self, in_channels, out_channels, I):
+        super(DenseLayer, self).__init__()
+        self.conv = nn.Conv2d(in_channels, out_channels, kernel_size=3, padding=3 // 2)
+        self.relu = nn.ReLU(inplace=True)
+        self.sk = SKFF(out_channels, height=2, reduction=8, bias=False)
+
+    def forward(self, x):
+        x1 = self.relu(self.conv(x))
+        # output = torch.cat([x, x1], 1) # -> RDB
+        output = self.sk((x, x1))
+        return output
+
+##---------- Selective Kernel Residual Dense Block (SK-RDB) ----------
+class SK_RDB(nn.Module):
+    def __init__(self, in_channels, growth_rate, num_layers):
+        super(SK_RDB, self).__init__()
+        self.identity = nn.Conv2d(in_channels, growth_rate, 1, 1, 0)
+        self.layers = nn.Sequential(
+            *[DenseLayer(in_channels, in_channels, I=i) for i in range(num_layers)]
+        )
+        self.lff = nn.Conv2d(in_channels, growth_rate, kernel_size=1)
+
+    def forward(self, x):
+        res = self.identity(x)
+        x = self.layers(x)
+        x = self.lff(x)
+        return res + x
+
+##---------- testNet ----------
+class SRMNet(nn.Module):
+    def __init__(self, in_chn=3, wf=96, depth=4):
+        super(SRMNet, self).__init__()
+        self.depth = depth
+        self.down_path = nn.ModuleList()
+        self.bili_down = bili_resize(0.5)
+        self.conv_01 = nn.Conv2d(in_chn, wf, 3, 1, 1)
+
+        # encoder of UNet-64
+        prev_channels = 0
+        for i in range(depth):  # 0,1,2,3
+            downsample = True if (i + 1) < depth else False
+            self.down_path.append(UNetConvBlock(prev_channels + wf, (2 ** i) * wf, downsample))
+            prev_channels = (2 ** i) * wf
+
+        # decoder of UNet-64
+        self.up_path = nn.ModuleList()
+        self.skip_conv = nn.ModuleList()
+        self.conv_up = nn.ModuleList()
+        self.bottom_conv = nn.Conv2d(prev_channels, wf, 3, 1, 1)
+        self.bottom_up = bili_resize(2 ** (depth-1))
+
+        for i in reversed(range(depth - 1)):
+            self.up_path.append(UNetUpBlock(prev_channels, (2 ** i) * wf))
+            self.skip_conv.append(nn.Conv2d((2 ** i) * wf, (2 ** i) * wf, 3, 1, 1))
+            self.conv_up.append(nn.Sequential(*[bili_resize(2 ** i), nn.Conv2d((2 ** i) * wf, wf, 3, 1, 1)]))
+            # *[nn.Conv2d((2 ** i) * wf, wf, 3, 1, 1), bili_resize(2 ** i)])
+            prev_channels = (2 ** i) * wf
+
+        self.final_ff = SKFF(in_channels=wf, height=depth)
+        self.last = conv3x3(prev_channels, in_chn, bias=True)
+
+    def forward(self, x):
+        img = x
+        scale_img = img
+
+        ##### shallow conv #####
+        x1 = self.conv_01(img)
+        encs = []
+        ######## UNet-64 ########
+        # Down-path (Encoder)
+        for i, down in enumerate(self.down_path):
+            if i == 0: # top layer
+                x1, x1_up = down(x1)
+                encs.append(x1_up)
+            elif (i + 1) < self.depth: # middle layer
+                scale_img = self.bili_down(scale_img)
+                left_bar = self.conv_01(scale_img)
+                x1 = torch.cat([x1, left_bar], dim=1)
+                x1, x1_up = down(x1)
+                encs.append(x1_up)
+            else: # lowest layer
+                scale_img = self.bili_down(scale_img)
+                left_bar = self.conv_01(scale_img)
+                x1 = torch.cat([x1, left_bar], dim=1)
+                x1 = down(x1)
+
+        # Up-path (Decoder)
+        ms_result = [self.bottom_up(self.bottom_conv(x1))]
+        for i, up in enumerate(self.up_path):
+            x1 = up(x1, self.skip_conv[i](encs[-i - 1]))
+            ms_result.append(self.conv_up[i](x1))
+
+        # Multi-scale selective feature fusion
+        msff_result = self.final_ff(ms_result)
+
+        ##### Reconstruct #####
+        out_1 = self.last(msff_result) + img
+
+        return out_1
+
+if __name__ == "__main__":
+    from thop import profile
+    input = torch.ones(1, 3, 256, 256, dtype=torch.float, requires_grad=False)
+
+    model = SRMNet(in_chn=3, wf=96, depth=4)
+    out = model(input)
+    flops, params = profile(model, inputs=(input,))
+
+    # RDBlayer = SK_RDB(in_channels=64, growth_rate=64, num_layers=3)
+    # print(RDBlayer)
+    # out = RDBlayer(input)
+    # flops, params = profile(RDBlayer, inputs=(input,))
+    print('input shape:', input.shape)
+    print('parameters:', params/1e6)
+    print('flops', flops/1e9)
+    print('output shape', out.shape)