Mastering OpenCV Android Application Programming

Salil Kapur, Nisarg Thakkar

• Éditeur: Packt Publishing
• Année: 2015
• ISBN:
  9781783988204
• Édition: 1
• Sujet: Informatica
• Sous-sujet: Informatica generale

If you are a Java and Android developer looking to enhance your skills by learning the latest features of OpenCV Android application programming, then this book is for you.

Mastering OpenCV Android Application Programming

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Table of Contents

Mastering OpenCV Android Application Programming

Credits

About the Authors

About the Reviewers

www.PacktPub.com

Support files, eBooks, discount offers, and more

Why subscribe?

Free access for Packt account holders

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. Applying Effects to Images

Getting started

Setting up OpenCV

Storing images in OpenCV

Linear filters in OpenCV

The mean blur method

The Gaussian blur method

The median blur method

Creating custom kernels

Morphological operations

Dilation

Erosion

Thresholding

Adaptive thresholding

Summary

2. Detecting Basic Features in Images

Creating our application

Edge and Corner detection

The Difference of Gaussian technique

The Canny Edge detector

The Sobel operator

Harris Corner detection

Hough transformations

Hough lines

Hough circles

Contours

Project – detecting a Sudoku puzzle in an image

Summary

3. Detecting Objects

What are features?

Scale Invariant Feature Transform

Understanding how SIFT works

Scale-space extrema detection

Keypoint localization

Orientation assignment

Keypoint descriptor

SIFT in OpenCV

Matching features and detecting objects

Brute-force matcher

FLANN based matcher

Matching the points

Detecting objects

Speeded Up Robust Features

SURF detector

SURF descriptor

Orientation assignment

Descriptor based on Haar wavelet responses

SURF in OpenCV

Oriented FAST and Rotated BRIEF

oFAST – FAST keypoint orientation

FAST detector

Orientation by intensity centroid

rBRIEF – Rotation-aware BRIEF

Steered BRIEF

Variance and correlation

ORB in OpenCV

Binary Robust Invariant Scalable Keypoints

Scale-space keypoint detection

Keypoint description

Sampling pattern and rotation estimation

Building the descriptor

BRISK In OpenCV

Fast Retina Keypoint

A retinal sampling pattern

A coarse-to-fine descriptor

Saccadic search

Orientation

FREAK in OpenCV

Summary

4. Drilling Deeper into Object Detection – Using Cascade Classifiers

An introduction to cascade classifiers

Haar cascades

LBP cascades

Face detection using the cascade classifier

HOG descriptors

Project – Happy Camera

Summary

5. Tracking Objects in Videos

Optical flow

The Horn and Schunck method

The Lucas and Kanade method

Checking out the optical flow on Android

Image pyramids

Gaussian pyramids

Laplacian pyramids

Gaussian and Laplacian pyramids in OpenCV

Basic 2D transformations

Global motion estimation

The Kanade-Lucas-Tomasi tracker

Checking out the KLT tracker on OpenCV

Summary

6. Working with Image Alignment and Stitching

Image stitching

Feature detection and matching

Image matching

Homography estimation using RANSAC

Verification of image matches using a probabilistic model

Bundle adjustment

Automatic panoramic straightening

Gain compensation

Multi-band blending

Image stitching using OpenCV

Setting up Android NDK

The layout and Java code

The C++ code

Summary

7. Bringing Your Apps to Life with OpenCV Machine Learning

Optical Character Recognition

OCR using k-nearest neighbors

Making a camera application

Handling the training data

Recognizing digits

OCR using Support Vector Machines

Solving a Sudoku puzzle

Recognizing digits in the puzzle

Summary

8. Troubleshooting and Best Practices

Troubleshooting errors

Permission errors

Some common permissions

Debugging code using Logcat

Best practices

Handling images in Android

Loading images

Processing images

Handling data between multiple activities

Transferring data via Intent

Using static fields

Using a database or a file

Summary

9. Developing a Document Scanning App

Let's begin

The algorithm

Implementing on Android

Summary

Index

Mastering OpenCV Android Application Programming

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 authors, 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.

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First published: July 2015

Production reference: 1230715

Published by Packt Publishing Ltd.

Livery Place

35 Livery Street

Birmingham B3 2PB, UK.

ISBN 978-1-78398-820-4

www.packtpub.com

Credits

Authors

Salil Kapur

Nisarg Thakkar

Reviewers

Radhakrishna Dasari

Noritsuna Imamura

Ashwin Kachhara

André Moreira de Souza

Commissioning Editor

Kartikey Pandey

Acquisition Editors

Harsha Bharwani

Aditya Nair

Content Development Editors

Ruchita Bhansali

Kirti Patil

Technical Editor

Ankur Ghiye

Copy Editor

Rashmi Sawant

Project Coordinator

Nidhi Joshi

Proofreader

Safis Editing

Indexer

Hemangini Bari

Graphics

Sheetal Aute

Production Coordinator

Nitesh Thakur

Cover Work

Nitesh Thakur

About the Authors

Salil Kapur is a software engineer at Microsoft. He earned his bachelor's degree in computer science from Birla Institute of Technology and Science, Pilani.

He has a passion for programming and is always excited to try out new technologies. His interests lie in computer vision, networks, and developing scalable systems. He is an open source enthusiast and...