Hello, I am trying to add an extra layer to the backbone of the Faster RCNN model (ResNet 50) but I am having trouble with the tensor shapes if anyone can help me. The code is as below, and I am trying to determine the meta_array_shape and backbone_output_shape variables. The first one is regarding the 2nd input which is a tensor of 3 columns, while the second is trying to match the output of the backbone so that they can be concatenated together.
        meta_array_shape = 3 
        backbone_output_shape = (512,3)
        
        self.meta_model = nn.Sequential(
            nn.Linear(meta_array_shape, backbone_output_shape),
            nn.BatchNorm1d(backbone_output_shape),
            nn.ReLU(),
            nn.Dropout(p=0.5)
        )

        X = self.faster_rcnn.backbone(X)

        # Metadata Net
        Y = self.meta_model(meta_in)
        
        # Concat Feature Maps
        X = torch.cat(X, Y)