Book Image

Multimedia Programming with Pure Data

By : Bryan, Wai-ching CHUNG
Book Image

Multimedia Programming with Pure Data

By: Bryan, Wai-ching CHUNG

Overview of this book

Preparing interactive displays, creating computer games, and conducting audio-visual performance are now achievable without typing lines of code. With Pure Data, a graphical programming environment, creating interactive multimedia applications is just visually connecting graphical icons together. It is straightforward, intuitive, and effective. "Multimedia Programming with Pure Data" will show you how to create interactive multimedia applications. You will learn how to author various digital media, such as images, animations, audio, and videos together to form a coherent title. From simple to sophisticated interaction techniques, you will learn to apply these techniques in your practical multimedia projects. You start from making 2D and 3D computer graphics and proceed to animation, multimedia presentation, interface design, and more sophisticated computer vision applications with interactivity. With Pure Data and GEM, you will learn to produce animations with 2D digital imagery, 3D modelling, and particle systems. You can also design graphical interfaces, and use live video for motion tracking applications. Furthermore, you will learn Audio signal processing, which forms the key aspect to multimedia content creation. Last but not least, Network programming using Pure Data extension libraries explores applications to other portable devices.
Table of Contents (17 chapters)
Multimedia Programming with Pure Data
Credits
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Chapter 5. Motion Detection

In this chapter, we plan to extend the interactivity beyond the use of mouse and keyboard. Motion detection needs the computer webcam to capture and detect the body movement of users. In Chapter 3, Image Processing, we worked with the pix_video object to obtain the live video stream. So far, we only displayed the video or applied effects on it. We have no idea about what is happening within the video image. In the coming sections, we try to make sense of the image.

In a video frame, all we know is the width, height of the frame, the number of pixels, and the red, green, and blue color components of each pixel. We have no idea whether there is a bird or pig in the frame. And we do not know whether the subject in the video frame is moving or not. In order to identify movement, we have to compare a frame with another reference frame. The following sections will introduce a number of topics including:

  • Obtaining the frame difference

  • Detecting presence

  • Detecting motion

  • Creating...