AI and Machine Learning for Coders

Chapter 18. Transfer Learning in JavaScript

In Chapter 17 you explored two methods for getting models into JavaScript: converting a Python-based model and using a preexisting model provided by the TensorFlow team. Aside from training from scratch, there’s one more option: transfer learning, where a model that was previously trained for one scenario has some of its layers reused for another. For example, a convolutional neural network for computer vision might have learned several layers of filters. If it was trained on a large dataset to recognize many classes, it may have very general filters that can be used for other scenarios.

To do transfer learning with TensorFlow.js, there are a number of options, depending on how the preexisting model is distributed. The possibilities fall into three main categories:

• If the model has a model.json file, created by using the TensorFlow.js converter to convert it into a layers-based model, you can explore the layers, choose one of them, and have that become the input to a new model that you train.

• If the model has been converted to a graph-based model, like those commonly found on TensorFlow Hub, you can connect feature vectors from it to another model to take advantage of its learned features.

• If the model has been wrapped in a JavaScript file for easy distribution, this file will give you some handy shortcuts for prediction or transfer learning by accessing embeddings or other feature vectors.

In this chapter, you’ll explore all ...