AR applications need trusted markers to show their tricks, like a magician saying, "See that top hat? There will be a rabbit soon!", where the top hat is the reference point. There are several types of reference points and each of them has their own advantages and spheres of application.
The following figure shows most common forms of markers:
The following are the short descriptions of these markers:
Symbol-based : This is a basic method. It is the recognition and tracking of special graphic markers that are officially known as fiducial markers or fiducials (from the Latin fiducia, which means trust), but are sometimes referred to as AR tags, tracking marks, artificial landmarks, and so on. In some cases, slightly modified QR code markers can be used as well.
Image-based: Graphic images such as photos or illustrations are split into reference points (the simplest way is to find a contrast frame around a picture). For instance, some applications use the one...