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

Single Shot Detectors – You Only Look Once


In this section we will move on to a slightly different kind of object detector called a single shot detectors. Single shot detectors try posing object detection as a regression problem. One of the main architectures under this category is the YOLO architecture (You Only Look Once) which we will explore in more detail now.

The main idea of the YOLO network is to optimise the computation of  predictions at various locations in the input image without using any sliding windows.In order to achieve this, the network outputs feature map in form of a  grid of size

 cells.

Each cell has B*5+C entries. Where "B" is the number of bounding boxes per cell, C is the number of class probabilities and 5 is the elements for each bounding box (x, y :center point coordinates of bounding box with respect to the cell in which it is located , w-width of the bounding box with respect to original image, h-height of the bounding box with respect to original image, confidence...