Evrim Yazgin
Cosmos science journalist
Spanish engineers have made the world’s first holograms that you can touch and manipulate, bringing science fiction into reality.
The achievement is detailed in a paper posted on the HAL open research archive.
“What we see in films and call holograms are typically volumetric displays,” says first author Elodie Bouzbib from the Public University of Navarra (UPNA). “These are graphics that appear in mid-air and can be viewed from various angles without the need for wearing virtual reality glasses. They are called true-3D graphics.”
The team says that commercial prototypes of volumetric displays exist. Examples are those developed by Voxon Photonics, based in South Australia, and Japanese company Brightvox Inc.
But these displays cannot be touched.
“We are used to direct interaction with our phones, where we tap a button or drag a document directly with our finger on the screen – it is natural and intuitive for humans,” says lead researcher Asier Marzo, also from the UPNA. “This project enables us to use this natural interaction with 3D graphics to leverage our innate abilities of 3D vision and manipulation.”
Volumetric displays work by projecting images onto a fast-oscillating sheet called a diffuser. About 2,880 images are projected a second. Due to this high speed, the image appears as a 3D object.
The diffuser is usually rigid. This means that a hand touching the volumetric display would either be injured or break the device.
A solution would be to use materials that are not so rigid. The challenge with this is that “elastic materials deform and require image correction,” Bouzbib says.
The team showed that images can be corrected by predicting how an image should look if the diffuser were not elastic and adjusting future oscillations of the elastic diffuser to accommodate manipulation.
The result is a virtual object which can be handled naturally.
“For example, grasping a cube between the index finger and thumb to move and rotate it, or simulating walking legs on a surface using the index and ring fingers,” the team says.
“Displays such as screens and mobile devices are present in our lives for working, learning, or entertainment. Having 3-dimensional graphics that can be directly manipulated has applications in education – for instance, visualising and assembling the parts of an engine. Moreover, multiple users can interact collaboratively without the need for virtual reality headsets. These displays could be particularly useful in museums, for example, where visitors can simply approach and interact with the content.”
