Book Image

Computer Vision for the Web

By : Foat Akhmadeev
Book Image

Computer Vision for the Web

By: Foat Akhmadeev

Overview of this book

This book will give you an insight into controlling your applications with gestures and head motion and readying them for the web. Packed with real-world tasks, it begins with a walkthrough of the basic concepts of Computer Vision that the JavaScript world offers us, and you’ll implement various powerful algorithms in your own online application. Then, we move on to a comprehensive analysis of JavaScript functions and their applications. Furthermore, the book will show you how to implement filters and image segmentation, and use tracking.js and jsfeat libraries to convert your browser into Photoshop. Subjects such as object and custom detection, feature extraction, and object matching are covered to help you find an object in a photo. You will see how a complex object such as a face can be recognized by a browser as you move toward the end of the book. Finally, you will focus on algorithms to create a human interface. By the end of this book, you will be familiarized with the application of complex Computer Vision algorithms to develop your own applications, without spending much time learning sophisticated theory.
Table of Contents (13 chapters)

Descriptors and object matching


Image features by themselves are a bit useless. Yes, we have found unique points on an image. But what did we get? Only pixels values and that's it. If we try to compare those values it will not give us much information. Moreover, if we change the overall image brightness, we will not find the same keypoints on the same image! Taking into account all of this, we need the information which surrounds our key points. Moreover, we need a method to efficiently compare this information. First, we need to describe the image features, which comes from image descriptors. In this part, we will see how those descriptors can be extracted and matched. The tracking.js and JSFeat libraries provide different methods for image descriptors. We will discuss both.

The BRIEF and ORB descriptors

The descriptors theory is focused on changes in an image pixels' intensities. The tracking.js library provides the Binary Robust Independent Elementary Features (BRIEF) descriptors and the...