Dear @ptrblck,
For data augmentation I’m only consider: flip Horizontal/Vertical et Rotation 90deg, 180deg, 270 deg, that is to say no pixel value scaling neither shifting. The batch_size is 128 for both test and train phases.
The Test set and Train set 100k each are originating from the same larger data set   600k and I have checked the statistics of both sets.
I do not know what I can do now. The problem comes from the last layer of the resnet model…