Train CNN's / Rotation and Mirroring
I am currently doing a project with similar industrial image processing task. I am detecting defects in a rectangular product image and from my experience, horizontal and vertical flipping of images has helped me a lot to augment my dataset and increase F1 score. Since I am not sure regarding your picture orientation I am unable to answer regarding other rotations. But if it has equal height and width then rotation of dataset makes sense. Try incorporating residual units into your CNN which has helped me massively since I had to use deeper networks to extract intricate features.