Computer Vision for the Web: Unleash the power of the Computer Vision algorithms in JavaScript to develop vision-enabled web content

Table of Contents

Computer Vision for the Web

Credits

About the Author

About the Reviewer

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Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the example code

Downloading the color images of this book

Errata

Piracy

Questions

1. Math Never Was So Simple!

Installation and core structure representation of JSFeat

Initializing the project

Understanding a digital image

Loading an image into a matrix

Basic matrix operations

Going deeper

Matrix displaying

Useful functions and where to use them

Sorting using JSFeat

Linear algebra

A perspective example

Summary

2. Turn Your Browser into Photoshop

Introducing the tracking.js library

Installation and image loading

Conversion between JSFeat and tracking.js image formats

What is filtering and how to use it?

Image convolution

The Gaussian filter and separate convolution

The box blur

The integral image

Basic edge detection

The Sobel filter

Other operators

Advanced image processing

The Canny edge detector

Histogram equalization

Summary

3. Easy Object Detection for Everyone

Detecting color objects

Using predefined colors with the tracking.js library

Using your own colors

Digging into the tracking.js API

Using the and

Building a custom tracker

Image features

Detecting key points

A practical example

Descriptors and object matching

The BRIEF and ORB descriptors

Descriptors implementation and their matching

Finding an object location

Summary

4. Smile and Wave, Your Face Has Been Tracked!

Face detection with JSFeat

Face detection using Haar-like features

Brightness binary features

Tagging people with tracking.js

Haar features with tracking.js

Tagging people in photos

Head tracking with Camshift

The idea behind head tracking

The head tracking application

Summary

5. May JS Be with You! Control Your Browser with Motion

Basic tracking with tracking.js

An example of an object tracking application

Controlling objects with the head motion

The Head-coupled perspective

Controlling a simple box

Optical flow for motion estimation

The Lucas-Kanade optical flow

Optical flow map with oflow

Track points with JSFeat

Zooming with gestures

Summary

6. What's Next?

Refresh your memory

Importance of client-side scripting

Other interesting libraries in Computer Vision

CCV library and its extensions

Face detection and more

Object detection with js-objectdetect

Summary

Index

Computer Vision for the Web

Computer Vision for the Web

Copyright © 2015 Packt Publishing

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.

Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author, nor Packt Publishing, and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.

Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.

First published: October 2015

Production reference: 1091015

Published by Packt Publishing Ltd.

Livery Place

35 Livery Street

Birmingham B3 2PB, UK.

ISBN 978-1-78588-617-1

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Credits

Author

Foat Akhmadeev

Reviewer

Noritsuna Imamura

Acquisition Editor

Tushar Gupta

Content Development Editor

Amey Varangaonkar

Technical Editor

Vivek Pala

Copy Editor

Pranjali Chury

Project Coordinator

Francina Pinto

Proofreader

Safis Editing

Indexer

Mariammal Chettiyar

Graphics

Disha Haria

Production Coordinator

Arvindkumar Gupta

Cover Work

Arvindkumar Gupta

About the Author

Foat Akhmadeev has 5 years of experience in software development and research. He completed his master's degree in the year 2014 from the Kazan Federal University, Russia. He has worked on different projects, including development of high-loaded websites written in Java and real-time object detection for mobile phones. He has an extensive background in the field of Computer Vision. He has also written a scientific paper on 3D reconstruction from a single image. For more information, you can visit his website at http://foat.me.

About the Reviewer

Noritsuna Imamura is a specialist in embedded Linux/Android-based Computer Vision, and is one of the main members of SIProp.org (http://siprop.org/). His main works are as follows:

ITRI Smart Glass, which is similar to Google Glass. He worked on this using Android 4.3 and OpenCV 2.4 in June 2014 (https://www.itri.org.tw/chi/Content/techTransfer/tech_tran_cont.aspx?&SiteID=1&MmmID=620622510147005345&Keyword=&MSid=4858).

The Treasure Hunting Robot, a brainwave controlling robot that he developed in February 2012 (http://www.siprop.org/en/2.0/index.php?product%2FTreasureHuntingRobot).

OpenCV for Android NDK. This has been included since Android 4.0.1 (http://tools.oesf.biz/android-4.0.1_r1.0/search?q=SIProp).

The Auto Chasing Turtle, a human face recognition robot with Kinect, which he developed in February 2011 (http://www.siprop.org/ja/2.0/index.php?product%2FAutoChasingTurtle).

Feel Sketch—an AR Authoring Tool and AR Browser as an Android application, which he developed in December 2009 (http://code.google.com/p/feelsketch/).

He can be contacted via e-mail at <[email protected]>.

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Preface

Computer Vision is one of the popular areas in computer science that have gained widespread importance lately. Besides, the power of personal computers has grown, thus opening the gate for developers to use Computer Vision algorithms directly on end user machines using client-side scripting. Nowadays, the most popular programming language for the web is JavaScript. It allows us to develop complex algorithms and run them directly in a web browser; this solves several major problems—the user needs nothing but a browser to run a web application, and as a developer, you get a lower load on your server. In this book, we will provide a comprehensive overview of the most popular JavaScript libraries and discuss the techniques they provide to help you in your initial steps in exciting fields, such as image processing and Computer Vision. This book covers Computer Vision methods by providing an intuitive overview of each algorithm and showing clear examples of the usage of libraries.

What this book covers

Chapter 1, Math Never Was So Simple! covers most of the necessary math operations that you need for using Computer Vision libraries and developing your own application.

Chapter 2, Turning Your Browser into Photoshop, introduces the most popular image processing techniques that are commonly used in the Computer Vision area.

Chapter 3, Easy Object Detection for Everyone, provides a detailed overview of object detection in photos and videos, starting from the basic examples, such as detecting objects by color, to the more complex examples such as feature detection.

Chapter 4, Smile and Wave, Your Face Has Been Tracked! covers detection of the face and face particles. In addition to this, it gives you an example of head tracking.

Chapter 5, May JS Be with You! Control Your Browser with Motion, extends the topic of object detection to object tracking and provides exhaustive examples. It also demonstrates how to create a human interface using gestures or head motion.

Chapter 6, What's Next? summarizes all that we will do throughout this book. Moreover, it provides references to several libraries that are not presented here.

What you need for this book

This book provides an