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

Chapter 5. Image Derivatives and Edge Detection

In the very first chapter, we made a distinction between the terms image processing and computer vision. We made it clear that the outputs of the operations that fall under the umbrella of image processing are images themselves. So, an image-processing operation will take an image as input and produce yet another image as its output. Essentially, all the techniques that we have covered so far are image-processing operations: grayscale transformations, image filtering, and image thresholding. Computer vision tasks are slightly more interesting. The inputs for computer vision algorithms are again, images. But, the outputs are what we call symbols. These symbols represent some form of semantic information that the algorithm has derived from the image. The kind of semantic inference that is done by vision algorithms is quite close to what human beings would do. An example of a computer vision task in an image would be to separate the foreground...