Book Image

OpenCV 3 Blueprints

By : Joseph Howse, Puttemans, Sinha
Book Image

OpenCV 3 Blueprints

By: Joseph Howse, Puttemans, Sinha

Overview of this book

Computer vision is becoming accessible to a large audience of software developers who can leverage mature libraries such as OpenCV. However, as they move beyond their first experiments in computer vision, developers may struggle to ensure that their solutions are sufficiently well optimized, well trained, robust, and adaptive in real-world conditions. With sufficient knowledge of OpenCV, these developers will have enough confidence to go about creating projects in the field of computer vision. This book will help you tackle increasingly challenging computer vision problems that you may face in your careers. It makes use of OpenCV 3 to work around some interesting projects. Inside these pages, you will find practical and innovative approaches that are battle-tested in the authors’ industry experience and research. Each chapter covers the theory and practice of multiple complementary approaches so that you will be able to choose wisely in your future projects. You will also gain insights into the architecture and algorithms that underpin OpenCV’s functionality. We begin by taking a critical look at inputs in order to decide which kinds of light, cameras, lenses, and image formats are best suited to a given purpose. We proceed to consider the finer aspects of computational photography as we build an automated camera to assist nature photographers. You will gain a deep understanding of some of the most widely applicable and reliable techniques in object detection, feature selection, tracking, and even biometric recognition. We will also build Android projects in which we explore the complexities of camera motion: first in panoramic image stitching and then in video stabilization. By the end of the book, you will have a much richer understanding of imaging, motion, machine learning, and the architecture of computer vision libraries and applications!
Table of Contents (9 chapters)
8
Index

Android specifics


In this section, we'll look at some Android-specific tasks: one is rendering an overlay on top of the camera view and the second is reading media files on Android.

The overlay is helpful for general information and debugging, and looks nice too! Think of it like the heads up display on a consumer camera.

The reading media files section is something we don't use in this chapter (we read media files using Python). However, if you decide to write an Android app that processes videos on the device itself, this section should get you started.

Threaded overlay

Now that we have the camera preview working, we want to render some additional information on top of it. We'll be drawing three things; first, a red circle to indicate whether recording is active, second, the current gyroscope values (angular velocity and estimated theta) just for information, and third, a safety rectangle. When stabilizing, we'll probably be cropping the image a bit. The rectangle will guide your video recording...