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Android Application Programming with OpenCV

Joseph Howse

For Java developers OpenCV is a fantastic opportunity to benefit from the popularity of image related mobile apps on Android. This book teaches you all you need to know about computer vision with practical projects.
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Book Details

ISBN 139781849695206
Paperback130 pages

About This Book

  • Set up OpenCV and an Android development environment on Windows, Mac, or Linux
  • Capture and display real-time videos and still images
  • Manipulate image data using OpenCV and Apache Commons Math
  • Track objects and render 2D and 3D graphics on top of them
  • Create a photo-capture and photo-sharing app that supports a variety of filters with a real-time preview feature

Who This Book Is For

This book is for Java developers who are new to computer vision and who would like to learn about how it is used in relation to application development. It is assumed that you have previous experience in Java, but not necessarily Android. A basic understanding of image data (for example pixels and color channels) would be helpful too. You are expected to have a mobile device running Android 2.2 (Froyo) or greater and it must have a camera.

Table of Contents

Chapter 1: Setting Up OpenCV
System requirements
Setting up a development environment
Building the OpenCV samples with Eclipse
Finding documentation and help
Chapter 2: Working with Camera Frames
Designing our app – Second Sight
Creating the Eclipse project
Enabling camera and disk access in the manifest
Creating menu and string resources
Previewing and saving photos in CameraActivity
Deleting, editing, and sharing photos in LabActivity
Chapter 3: Applying Image Effects
Adding files to the project
Mixing color channels
Making subtle color shifts with curves
Processing a neighborhood of pixels with convolution filters
Adding the filters to CameraActivity
Chapter 4: Recognizing and Tracking Images
Adding files to the project
Understanding image tracking
Writing an image tracking filter
Adding the tracker filters to CameraActivity
Chapter 5: Combining Image Tracking with 3D Rendering
Adding files to the project
Defining the ARFilter interface
Building projection matrices in CameraProjectionAdapter
Modifying ImageDetectionFilter for 3D tracking
Rendering the cube in ARCubeRenderer
Adding 3D tracking and rendering to CameraActivity
Learning more about 3D graphics on Android

What You Will Learn

  • Install OpenCV and an Android development environment on Windows, Mac, or Linux
  • Capture, display, and save images
  • Make images accessible to other apps via Android's MediaStore and Intent classes
  • Integrate OpenCV events and views with Android's standard activity lifecycle and view hierarchy
  • Learn how OpenCV uses matrices to store data about images, recognizable features in images, and camera characteristics
  • Apply curves and other color transformations to simulate the look of old photos, movies, or video games
  • Apply convolution filters that sharpen, blur, emboss, or darken edges and textures in an image
  • Track real-world objects, especially printed images, in 2D and 3D space
  • Extract camera data from Android SDK and use it to construct OpenCV and OpenGL projection matrices
  • Render basic 3D graphics in OpenGL

In Detail

Take a smartphone from your pocket, and within a few seconds, you can snap a photo, manipulate it, and share it with the world. You have just achieved mass production of image data. With a computer vision library such as OpenCV, you can analyze and transform copious amounts of image data in real time on a mobile device. The upshot to this is that you, as developers, can provide mobile users with many new kinds of images, constantly highlighting certain visual features that are of artistic or practical interest. Android is a convenient platform for such experiments because it uses a high-level language (Java), it provides standardized interfaces for sharing image data between applications, and it is mostly open source, so everyone can study its implementation.

Android Application Programming with OpenCV is a practical, hands-on guide that covers the fundamental tasks of computer vision—capturing, filtering, and analyzing images-with step-by-step instructions for writing both an application and reusable library classes.

Android Application Programming with OpenCV looks at OpenCV's Java bindings for Android and dispels mysteries such as which version of these bindings to use, how to integrate with standard Android functionality for layout, event handling, and data sharing, and how to integrate with OpenGL for rendering. By following the clear, concise, and modular examples provided in this book, you will develop an application that previews, captures, and shares photos with special effects based on color manipulation, edge detection, image tracking, and 3D rendering.
Beneath the application layer, you will develop a small but extensible library that you can reuse in your future projects. This library will include filters for selectively modifying an image based on edge detection, 2D and 3D image trackers, and adapters to convert the Android system's camera specifications into OpenCV and OpenGL projection matrices. If you want a quick start in computer vision for Android, then this is the book for you.

By the end of Android Application Programming with OpenCV, you will have developed a computer vision application that integrates OpenCV, Android SDK, and OpenGL.


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