Book Image

Hands-On Convolutional Neural Networks with TensorFlow

By : Iffat Zafar, Giounona Tzanidou, Richard Burton, Nimesh Patel, Leonardo Araujo
Book Image

Hands-On Convolutional Neural Networks with TensorFlow

By: Iffat Zafar, Giounona Tzanidou, Richard Burton, Nimesh Patel, Leonardo Araujo

Overview of this book

Convolutional Neural Networks (CNN) are one of the most popular architectures used in computer vision apps. This book is an introduction to CNNs through solving real-world problems in deep learning while teaching you their implementation in popular Python library - TensorFlow. By the end of the book, you will be training CNNs in no time! We start with an overview of popular machine learning and deep learning models, and then get you set up with a TensorFlow development environment. This environment is the basis for implementing and training deep learning models in later chapters. Then, you will use Convolutional Neural Networks to work on problems such as image classification, object detection, and semantic segmentation. After that, you will use transfer learning to see how these models can solve other deep learning problems. You will also get a taste of implementing generative models such as autoencoders and generative adversarial networks. Later on, you will see useful tips on machine learning best practices and troubleshooting. Finally, you will learn how to apply your models on large datasets of millions of images.
Table of Contents (17 chapters)
Title Page
Copyright and Credits
Packt Upsell
Contributors
Preface
Index

Evaluating a trained model


We have put together all the pieces we need in order to train our model. The last thing before we start training is that we want to create some nodes in our graph that will allow us to test how good our model has done after we have finished training it.

We will create a node that calculates the accuracy of our model.

Tf.equal will return a Boolean list indicating where the two supplied lists are equal. Our two lists, in this case, will be the label and the output of our model, after finding the indices of the max values:

correct_prediction = tf.equal(tf.argmax(model_out,1), tf.argmax(y,1)) 

We can then use reduce_mean again to get the average number of correct predictions. Don't forget to cast our boolean correct_prediction list back to float32:

accuracy = tf.reduce_mean(tf.cast(correct_prediction, tf.float32))