In this chapter, we first gave a quick overview on what is transfer learning and why we can and should use it to retrain pretrained deep learning image classification models. Then we presented detailed information on how to retrain an Inception v3-based model and a MobileNet model so we can better understand and recognize our best friends. After that, we first showed how to use the retrained models in the TensorFlow sample iOS and Android apps, then gave step-by-step tutorials on how to add TensorFlow to your own iOS app, both Objective-C and Swift-based, and your own Android app.

Now that we have our best friends, with a few nice and clean tricks, covered, we know there are a lot of other guys out there, good or bad. In the next chapter, we'll learn how to be smarter, how to recognize all the interesting objects in a picture, and locate them, on your smart phone...