If you want to create your own natural feature-tracking targets, it is important to design them in a way that they can be well recognized and tracked by the AR system. The basics of natural feature targets were explained in the Understanding natural feature tracking targets section of Chapter 5, Same as Hollywood – Virtual on Physical Objects. The basic requirement for well-traceable targets is that they possess a high number of local features. But how do you go along if your target is not well recognized? To a certain extent, you can improve the tracking by using the forthcoming tips.
First, you want to make sure that your images have enough local contrast. A good indicator for the overall contrast in your target is to have a look at the histogram of its greyscale representation in any photo editing software such as GIMP or Photoshop. You generally want a widely distributed histogram instead of one with few spikes, as shown in the following figure:
To increase...