Why does my CIFAR 100 CNN model mainly predict two classes?

Question

I am currently trying to get a decent score (> 40% accuracy) with Keras on CIFAR 100. However, I\'m experiencing a weird behaviour of a CNN model: It tends to predict some c

Answer 1

If you get good accuracy during training and validation, but not when testing, make sure you do exactly the same preprocessing on your dataset in both cases. Here you have when training:

X_train /= 255
X_val /= 255
X_test /= 255

But no such code when predicting for your confusion matrix. Adding to testing:

X_val /=  255.

Gives the following nice looking confusion matrix: