A depth camera measures the distance from its sensor to objects and provides us with information about the 3D scene it sees. Using this information, it is easy to analyze and recognize 3D objects in the scene, including humans and their body parts. So today, depth cameras are the most used sensors for providing touchless interactions in most of the interactive projects. In this chapter, we will learn how to use depth cameras in openFrameworks projects using the ofxOpenNI addon. Also, we will consider the example of using depth images for making a flat surface such as a wall, a table, or a floor interactive.
The topics covered are as follows: