In the last chapter you learned how to overlay digital content on the view of the physical world. However, if you move around with your device, point it somewhere else, the virtual content will always stay at the same place on your screen. This is not exactly what happens in AR. The virtual content should stay at the same place relative to the physical world (and you can move around it), not remaining fixed on your screen.
In this chapter we will look at how to achieve dynamic registration between digital content and the physical space. If at every time step, we update the position of moving objects in our application, we will create the feeling that digital content sticks to the physical world. Following the position of moving elements in our scene can be defined as tracking, and this is what we will use and implement in this chapter. We will use sensor-based AR to update the registration between digital content and physical space. As some of these sensors...