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

Rolling average

The main result of our detection is the three values of the polynomial fit, for each lane. Following the same principle of the previous section, we can deduce that they cannot change much between frames, so we could consider the average of some of the previous frames, to reduce noise.

There is a technique called the exponentially weighted moving average (or rolling average), which can be used to easily compute an approximate average on some of the last values of a stream of values.

Given beta, a parameter greater than zero and typically close to one, the moving average can be computed like this:

moving_average = beta * prev_average + (1-beta)*new_value

As an indication, the number of frames that most affect the average is given by the following:

1 / (1 - beta)

So, beta = 0.9 would average 10 frames, and beta = 0.95 would average 20 frames.

This concludes the chapter. I invite you to check the full code on GitHub and to play around with it. You can...