Holography and Volumetric displays
Holography is a method used to make three dimensional images which are known as holograms.
Holographic projection involves certain factors.
These factors include a laser, diffraction, interference, light intensity recording and a proper illumination for the recording to be done.
When the position and orientation of the viewing system changes the image changes as well, the same way as if the object were present therefore making the image look three-dimensional.
How to project 3D images in the air
The experiment to project 3D images in the air was first carried out by National Institute of Advanced Industrial science in Japan. The experiment was able to project optical illusions in the air that looked 3 dimensional because of the parallax variance between the eyes of the person viewing, a side effect was that it caused discomfort over prolonged viewing. This device have been modified but until now the distance to project 3D images is limited to a distance of two to three meters.
Difference between holographic and volumetric displays
Holographic displays - these kind of displays use a technology that is able to give the viewer the four eye mechanism which are motion parallax, accommodation, convergence and binocular disparity without wearing special glasses. This method is also free from any kind of visual fatigue to the human eye.
Volumetric displays - these displays use physical instruments to show points of light within a volume, they make use of voxels in the place of pixels.
Factors limiting 3D displays
Although there have been improved research on 3D displays it have become very difficult to realize any tangible development or any commercial gain of the 3D displays. This is because the equipments used to make these displays are specialized, the technology requires larger amounts of bandwidth over normal 2 dimensional displays and the costs involved are very high.
How volumetric displays are being used in the world today
Volumetric displays have been used in the entertainment industry to create movies and make them more interesting for audiences.