Parameters of model

1

Hello there! I am trying to train a model for segmentation for the first time. I found this way to load the model and the following loss function:

from torchvision.models.segmentation.deeplabv3 import DeepLabHead

def createDeepLabv3(outputchannels=2):
    """DeepLabv3 class with custom head
    Args:
        outputchannels (int, optional): The number of output channels
        in your dataset masks. Defaults to 1.
    Returns:
        model: Returns the DeepLabv3 model with the ResNet101 backbone.
    """
    model = models.segmentation.deeplabv3_resnet101(pretrained=True)
    model.classifier = DeepLabHead(2048, outputchannels)
    # Set the model in training mode
    model.train()
    return model

Loss function:

import torch.nn.functional as F

class DiceBCELoss(nn.Module):
    def __init__(self, weight=None, size_average=True):
        super(DiceBCELoss, self).__init__()

    def forward(self, inputs, targets, smooth=1):
        
        #comment out if your model contains a sigmoid or equivalent activation layer
        inputs = F.sigmoid(inputs)       
        
        #flatten label and prediction tensors
        print(inputs[0])
        print(targets[0])
        inputs = inputs.view(-1)
        targets = targets.view(-1)
        
        intersection = (inputs * targets).sum()                            
        dice_loss = 1 - (2.*intersection + smooth)/(inputs.sum() + targets.sum() + smooth)  
        BCE = F.binary_cross_entropy(inputs, targets, reduction='mean')
        Dice_BCE = BCE + dice_loss
        
        return Dice_BCE

I end up getting the following error:

AttributeError: ‘collections.OrderedDict’ object has no attribute ‘sigmoid’

AttributeError: ‘collections.OrderedDict’ object has no attribute ‘view’
I assume that I loaded the model incorrectly.

As I understand it, the classifier of the pre-trained model is simply replaced here with a classifier with random weights. I already tried transfer learning and there I replaced only the last layer. So, I have a question, how to change the classifier correctly and how many classes should I specify, one or two, given that I am segmenting stones. And ofcource explain me please, how to load model correctly?

2

Based on the error messages it seems the input to DiceBCELoss.forward is a dict while a tensor is expected.
Note that deeplabv3_resnet101 will indeed return a dict containing out and aux keys so you might want to index the out tensor before passing it to the loss function.

1 Like
3

Thank you a lot! Didn’t know this and when read about deeplabv3 did not pay attention to this detail. Sorry for my inattention