Grad-CAM implementation in Keras for saliency maps
[1] Ramprasaath R. Selvaraju, Michael Cogswell, Abhishek Das, Ramakrishna Vedantam, Devi Parikh, Dhruv Batra
"Grad-CAM: Visual Explanations from Deep Networks via Gradient-based Localization"
https://arxiv.org/abs/1610.02391
[2] http://www.hackevolve.com/where-cnn-is-looking-grad-cam/
[3] https://www.youtube.com/watch?v=YwjDRw0MELw
I added comments to make the code understandable to everyone