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

What does LBP capture?


We have described how the LBP operator is applied to images, and we have also discussed some variants of it. Now obviously, if we are studying LBP in such great detail, we would definitely be applying it somewhere! We are going to use the LBP operator on the (cropped and aligned) facial images that we obtained in the last chapter. But before we jump in and start running the LBP code on our face images, let's take a step back and ponder upon a very important question, "What does the LBP capture?"

We have already gone through the mechanics of calculating the LBP code for a pixel, and we have seen that the end result is a 256 (or a 58) dimensional histogram. But, what does that histogram tell us about the image? Well, you can say that histograms give us frequency counts and you would be right. It was easy to visualize this in the case of the image histograms from Chapter 4, Image Histograms where the histogram bins were the grayscale values. Hence, it was easy to intuitively...