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

Early stopping

When should we stop training? That's a good question! Ideally, you want to stop at the minimum validation error. While you cannot know this in advance, you can check the losses and get an idea of how many epochs you need. However, when you train your network, sometimes you need more epochs depending on how you tune your model, and it is not simple to know in advance when to stop.

We already know that we can use ModelCheckpoint, a callback of Keras, to save the model with the best validation error seen during training.

But there is also another very useful callback, EarlyStopping, which stops the training when a predefined set of conditions happen:

stop = EarlyStopping(min_delta=0.0005, patience=7, verbose=1)

The most important parameters to configure early stopping are the following:

  • monitor: This decides which parameter to monitor, by default: validation loss.
  • min_delta: If the difference in validation loss between epochs is below this value...