Book Image

Learning OpenCV 3 Application Development

By : Samyak Datta
Book Image

Learning OpenCV 3 Application Development

By: Samyak Datta

Overview of this book

Computer vision and machine learning concepts are frequently used in practical computer vision based projects. If you’re a novice, this book provides the steps to build and deploy an end-to-end application in the domain of computer vision using OpenCV/C++. At the outset, we explain how to install OpenCV and demonstrate how to run some simple programs. You will start with images (the building blocks of image processing applications), and see how they are stored and processed by OpenCV. You’ll get comfortable with OpenCV-specific jargon (Mat Point, Scalar, and more), and get to know how to traverse images and perform basic pixel-wise operations. Building upon this, we introduce slightly more advanced image processing concepts such as filtering, thresholding, and edge detection. In the latter parts, the book touches upon more complex and ubiquitous concepts such as face detection (using Haar cascade classifiers), interest point detection algorithms, and feature descriptors. You will now begin to appreciate the true power of the library in how it reduces mathematically non-trivial algorithms to a single line of code! The concluding sections touch upon OpenCV’s Machine Learning module. You will witness not only how OpenCV helps you pre-process and extract features from images that are relevant to the problems you are trying to solve, but also how to use Machine Learning algorithms that work on these features to make intelligent predictions from visual data!
Table of Contents (16 chapters)
Learning OpenCV 3 Application Development
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface

The Canny edge detector


Having learned about and also implemented the Sobel edge detector in the previous section, we now turn our attention to yet another edge detection algorithm, namely the Canny edge detector. It's named after its inventor John F. Canny who came up with the algorithm in 1986. The algorithm is much more involved than the Sobel edge detector and is considered to be superior to the latter.

The basic guiding principles powering the Canny detector remain the same. This means that we will still use the gradient values as indicators of whether the pixel belongs to a potential edge region or not. However, there are certain additional steps that are performed by the detector to improve the quality of detected edges. We provide a brief explanation of the same. Note that we won't be getting into the intricate mathematical details behind Canny. Rather, we would only be sharing the intuitions that motivate the additional steps that the algorithm performs. In addition to improving...