Book Image

Deep Learning with Theano

By : Christopher Bourez
Book Image

Deep Learning with Theano

By: Christopher Bourez

Overview of this book

This book offers a complete overview of Deep Learning with Theano, a Python-based library that makes optimizing numerical expressions and deep learning models easy on CPU or GPU. The book provides some practical code examples that help the beginner understand how easy it is to build complex neural networks, while more experimented data scientists will appreciate the reach of the book, addressing supervised and unsupervised learning, generative models, reinforcement learning in the fields of image recognition, natural language processing, or game strategy. The book also discusses image recognition tasks that range from simple digit recognition, image classification, object localization, image segmentation, to image captioning. Natural language processing examples include text generation, chatbots, machine translation, and question answering. The last example deals with generating random data that looks real and solving games such as in the Open-AI gym. At the end, this book sums up the best -performing nets for each task. While early research results were based on deep stacks of neural layers, in particular, convolutional layers, the book presents the principles that improved the efficiency of these architectures, in order to help the reader build new custom nets.
Table of Contents (22 chapters)
Deep Learning with Theano
Credits
About the Author
Acknowledgments
About the Reviewers
www.PacktPub.com
Customer Feedback
Preface
Index

Unsupervised learning with co-localization


The first layers of the digit classifier trained in Chapter 2, Classifying Handwritten Digits with a Feedforward Network as an encoding function to represent the image in an embedding space, as for words:

It is possible to train unsurprisingly the localization network of the spatial transformer network by minimizing the hinge loss objective function on random sets of two images supposed to contain the same digit:

Minimizing this sum leads to modifying the weights in the localization network, so that two localized digits become closer than two random crops.

Here are the results:

(Spatial transformer networks paper, Jaderberg et al., 2015)