Book Image

OpenCV 4 Computer Vision Application Programming Cookbook - Fourth Edition

By : David Millán Escrivá, Robert Laganiere
Book Image

OpenCV 4 Computer Vision Application Programming Cookbook - Fourth Edition

By: David Millán Escrivá, Robert Laganiere

Overview of this book

OpenCV is an image and video processing library used for all types of image and video analysis. Throughout the book, you'll work with recipes to implement a variety of tasks. With 70 self-contained tutorials, this book examines common pain points and best practices for computer vision (CV) developers. Each recipe addresses a specific problem and offers a proven, best-practice solution with insights into how it works, so that you can copy the code and configuration files and modify them to suit your needs. This book begins by guiding you through setting up OpenCV, and explaining how to manipulate pixels. You'll understand how you can process images with classes and count pixels with histograms. You'll also learn detecting, describing, and matching interest points. As you advance through the chapters, you'll get to grips with estimating projective relations in images, reconstructing 3D scenes, processing video sequences, and tracking visual motion. In the final chapters, you'll cover deep learning concepts such as face and object detection. By the end of this book, you'll have the skills you need to confidently implement a range of computer vision algorithms to meet the technical requirements of your complex CV projects.
Table of Contents (17 chapters)

Estimating the optical flow

When a scene is observed by a camera, the observed brightness pattern is projected on the image sensor and thus forms an image. In a video sequence, we are often interested in capturing the motion pattern, that is, the projection of the 3D motion of the different scene elements on an image plane. This image of projected 3D motion vectors is called the motion field. However, it is not possible to directly measure the 3D motion of scene points from a camera sensor. All we observe is a brightness pattern that is in motion from frame to frame. This apparent motion of the brightness pattern is called the optical flow. You might think that the motion field and optical flow should be equal, but this is not always true. An obvious case can be the observation of a uniform object; for example, if a camera moves in front of a white wall, then no optical flow is...