I am a beginner in deep_learning and my graduation thesis is about semantic segmentation. However I received a ValueError when using library "segmentation-models"

I don't understand it (Because of my limited English or lack of knowlege...), and the x_val and y_val both have 3 channels and they are numpy arrays:

Please help me!!! Thanks a lot!

Solve this error and train my model.

CodePudding user response：

It seems that you have 3 channels, but the shape of the output has only 1 channel.
The UNET initialization has a parameter called classes, which defines the output shape. You should probably set this to classes=3 when definining the model.
See documentation in https://segmentation-models.readthedocs.io/en/latest/api.html#unet
And more specifically, note the following snippet:

classes – a number of classes for output (output shape - (h, w, classes)).

Clarification: The number of input channels is of no real consequence here. The channel count changes multiple times througout the convolutional layers, the skip-connection concatenations, etc., so the number of output channels vs the number of label channels is the only thing that matters in this context. train_x could have 1 channel, 37 channels, or any other necessary number of channels, and the error you're getting is only related to comparing y_train (and y_val) to the logits/softmax/label_estimations, or whatever you want to call them. Which is set, as mentioned above, by explicitly using the classes parameter.