  Interpreting how does deep neural networks (DNNs) make predictions is a vital
field in artificial intelligence, which hinders wide applications of DNNs.
Visualization of learned representations helps we humans understand the vision
of DNNs. In this work, visualized images that can activate the neural network
to the target classes are generated by back-propagation method. Here, rotation
and scaling operations are applied to introduce the transformation invariance
in the image generating process, which we find a significant improvement on
visualization effect. Finally, we show some cases that such method can help us
to gain insight into neural networks.
