Book Image

Hands-On Vision and Behavior for Self-Driving Cars

By : Luca Venturi, Krishtof Korda
Book Image

Hands-On Vision and Behavior for Self-Driving Cars

By: Luca Venturi, Krishtof Korda

Overview of this book

The visual perception capabilities of a self-driving car are powered by computer vision. The work relating to self-driving cars can be broadly classified into three components - robotics, computer vision, and machine learning. This book provides existing computer vision engineers and developers with the unique opportunity to be associated with this booming field. You will learn about computer vision, deep learning, and depth perception applied to driverless cars. The book provides a structured and thorough introduction, as making a real self-driving car is a huge cross-functional effort. As you progress, you will cover relevant cases with working code, before going on to understand how to use OpenCV, TensorFlow and Keras to analyze video streaming from car cameras. Later, you will learn how to interpret and make the most of lidars (light detection and ranging) to identify obstacles and localize your position. You’ll even be able to tackle core challenges in self-driving cars such as finding lanes, detecting pedestrian and crossing lights, performing semantic segmentation, and writing a PID controller. By the end of this book, you’ll be equipped with the skills you need to write code for a self-driving car running in a driverless car simulator, and be able to tackle various challenges faced by autonomous car engineers.
Table of Contents (17 chapters)
1
Section 1: OpenCV and Sensors and Signals
5
Section 2: Improving How the Self-Driving Car Works with Deep Learning and Neural Networks
12
Section 3: Mapping and Controls

Improving the validation accuracy with dropout

A source of overfitting is the fact that the neural network relies more on some neurons to draw its conclusions, and if those neurons are wrong, the network is wrong. One way to reduce this problem is simply to randomly shut down some neurons during training while keeping them working normally during inference. In this way, the neural network learns to be more resistant to errors and to generalize better. This mechanism is called dropout, and obviously, Keras supports it. Dropout increases the training time, as the network needs more epochs to converge. It might also require a bigger network, as some neurons are randomly deactivated during training. It is also more useful when the dataset is not very big for the network, as it is more likely to overfit. In practice, as dropout is meant to reduce overfitting, it brings little benefit if your network is not overfitting.

A typical value of dropout for dense layers is 0.5, though we might...