Volumetric 3D display based on a DLP projection prototyped

Jason Geng, Vice President for the IEEE ITS Society, reveals a prototype of a true 3D monochrome volumetric display prototype based on projection technology.

According to Geng, nearly 50% of the human brain's capability is devoted to processing visual information and that "flat images and 2D displays do not harness the brain's power effectively". According to Geng, there are four depth cues which the brain uses to process stereoscopic information; a) the focus: where the eyes focus on a specific object in a 3D scene, b) convergence: where the eyes converge so each eye sees the 3D object simultaneously, c) motion parallax: where speed indicates distance from the eyes (for example, when you look at the landscape when travelling in a car) and d) binocular disparity: the differences between the left and right images.

To address each cue, IEEE Intelligent Transportation Systems (ITS) Society have created a volumetric display – a ‘true’ 3D display that uses voxels rather than pixels. Each voxel emits light from a physical space so the brain is not being deceived into processing an 'illusion'. It is more akin to looking at a real object, where the focussing and converging muscles can naturally focus on an object at the same time. The reason many people find watching 3D TV and 3D movies in the cinema is because the viewer's eyes are being forced to converge and focus on different points (the focus point will always be the screen but the eyes will be required to converge beyond the screen point for an object in positive space – not a natural experience).

For the scientific amongst you, the DLP/Helix volumetric system records 3D object information by projecting light out of source which is reflected by a polarizing beamsplitter cube towards a spatial light modulator (SLM), whose image patterns are generated by a host personal computer (PC). 

To re-create the 3D image, a helix screen is rotated in sync with the DLP which projects high speed images. When the helix screen intercepts each pixel (which, due to its shape, will constantly move along the z-axis), it shows up as a pixel (voxel) in space. This process happens so fast that, like the persistence of vision phenomena utilised in regular television, the brain adds the points together over time to see one volumetric 3D image without the need to wear glasses.

The unique features of the DLP/Helix 3D display design include an inherent parallel architecture for voxel-addressing, high-speed and high-spatial resolution, and no need for viewers to wear special glasses or a helmet.

The prototype volumetric display has a resolution of 150 million voxels and is currently only able to display a monochrome image. However, it can display transparent 3D video and viewers can walk around an object to see different angles.

Jason Geng says “Such a 3D display provides both physiological and psychological depth cues to human viewers for truthfully perceiving objects in 3D space.”

In the future, he and his team will develop a full-colour version of the display system with a sufficient 3D image refresh rate. i

For more information visit the official website.

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