When to tell if our CNN model is overfitting?

Question

i have this model that i trained with 100 epochs : Model with 100 Epoch

and then i save the model and train for another 100 epoch (total 200 epoch): Model with additional 100 epoch (200 epoch)

my question is, is my model not overfitting ? is it optimal ?

Answer 1

Over fitting is when your model scores very highly on your training set and poorly on a validation test set (or real life post-training predictions).

When you are training your model make sure that you have split your training dataset into two subsets. One for training and one for validation. If you see that your validation accuracy is decreasing as training goes on it means that your CNN has "overfitted" to the training set specifically and should not be generalized.

There are many ways to combat overfitting that should be used while training your model. Seeking more data and using harsh dropout are popular ways to ensure that a model is not overfitting. Check out this article for a good description of your problem and possible solutions.