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

Summary


In this chapter, we learnt how to convert our image into a feature vector, or a sequence of values. Specifically, we looked at one particular feature descriptor: the local binary pattern (or, LBP) operator. Apart from the traditional LBP formulation, we also saw some common variants that are used. An important takeaway from this chapter is that the LBP captures the "texture" of the input image. We also looked at how such texture information can help us capture the subtle variations present in facial images.

Local binary pattern is just one of the many possible feature descriptors that have been proposed in Computer Vision literature. Some other examples include Histogram of Oriented Gradients (HoG), SIFT and SURF. HoG uses the concept of image derivatives whereas SIFT and SURF are much more sophisticated feature descriptors (they are patented algorithms as well). In fact, similar in spirit to LBP, we have yet another feature descriptor called local ternary patterns (LTP). Instead...