Trackers

Introduction  

We all know that the use of AR/VR technologies is increasing day by day among companies involved in mobile computing and business applications. So before we understand what trackers are and their uses in AR/VR, let us understand the meaning of augmented reality and virtual reality.

Augmented reality(AR)

Augmented reality is an interactive experience of a real-world environment that is achieved using sounds, digital elements, and sensory stimuli via technology. Many companies use AR to promote their product or service and collect unique user data. So AR basically adds to the real environment. Some examples of augmented reality daily are 

1. Snapchat: It is a popular social media application used for messaging. this app is full of trendy and catchy filters. Firstly user's face is detected using artificial intelligence and then imposed on the face of the user giving it a real look with the help of augmented reality and artificial intelligence.
    
2. Hololens: It is a technology in which the screen of the gadget is levitated in front of users. It is made user-friendly by adding gesture commands, voice commands head tracking, etc.
    
3. Some other examples are the Pokemon go game, interior decoration apps, Google Glass, etc.

Virtual reality(VR)

In contrast to AR, virtual reality creates an entirely different environment created and rendered using computers. It is widely used by companies in different fields. For example:

1. It is used in the sports industry. It is used by coaches and players to train more efficiently and improve their timing in particular situations.
    
2. It is also used in mental health for treating post-traumatic stress. It is also used to treat anxiety, depression, and phobias.
    
3. It is used in the fashion industry, in the education industry, and also being used by the military.

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Trackers

Trackers in augmented reality are specific patterns or images that an application can recognize. Once the application finds a pattern it keeps a track of the real-world space so that it can accurately place a virtual object using trackers.

For example, if we want to place a 3d object in a moving video, then trackers are used to track points of placement of an object in the video. After getting the full information, a 3d object is placed on those points. Trackers are also known as targets.

Basically, Trackers can be of two types:

• Fixed Target tracker
• Moving Target tracker

Fixed Target Tracker

In a fixed target tracker, the target will appear at the point where the image was first detected. To get the best results target should be placed in a fixed position. And even if the tracker leaves the image 3d object will be placed correctly.

Moving Target Tracker

In a moving target tracker, as the tracker moves the 3d object will also move. If the target moves out of the image then the object will disappear.

Properties of target tracker:

• Visible: Trackers are visible if the visible box is checked.
• Layer: We need to define which trackers are applied on which layers.
• Transformation: Position, rotation, orientation, and scale of trackers can be changed.

Some other types of trackers are :

• World tracking
• Object tracking
• Image tracking
• Wikitude Multiple trackers

World tracking

In world tracking, trackers track the flat horizontal surface and tell the devices about it.

Google calls it motion tracking. These are good for tracking large environments.

Object tracking

Object tracking is tracking 3d objects before placing them on trackers so that the software is capable of recognizing them.

Image Tracking

It is similar to Object tracking. In image tracking, a 2d image is used for reference. It works on both horizontal and vertical surfaces.

Wikitude multiple trackers

It is used in advanced AR experiences and usually mixes multiple trackers. Developers can track objects, images, and environments to build advanced AR experiences.