In the collective imagination, touch holograms represent the Holy Grail of human-computer interaction. Today, thanks to a team of Spanish engineers, this technology has finally left the realm of imagination to become tangible reality. Researchers atPublic University of Navarra (UPNA) have developed volumetric displays that not only project 3D images into the air that can be viewed from any angle without the need for a headset, but also allow users to touch and manipulate them. “We are used to interacting directly 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,” explains the lead researcher Asier March.
What are touch holograms really?
I need to make a necessary clarification: what we commonly call “holograms” in science fiction films (think Star Wars or Iron Man) are not technically holograms in the strict sense. “What we see in films and call holograms are typically volumetric displays,” he clarifies. Elodie Bouzbib, first author of the studyPublic University of Navarra. These are graphics that appear in mid-air and can be viewed from various angles without wearing virtual reality glasses. The technical term for touch holograms is “true-3D graphics.”
The real revolution here is not so much the three-dimensional visualization (there are already commercial prototypes developed by companies such as Voxon Photonics in Australia and Japan Brightvox Inc), as well as the ability to physically interact with these virtual objects. Until now, volumetric displays were “look but don’t touch.” Now, thanks to this technological breakthrough, we can finally directly manipulate three-dimensional images as we would with real objects.
Technology is bridging the gap between what we imagine and what we can actually achieve. Just a few years ago, this would have been pure science fiction.
The technical solution
The basic operation of traditional volumetric displays is fascinating: project images onto a rapidly oscillating sheet called a “diffuser”. The magic happens when approximately 2.880 images are projected every second. Because of this high speed, the image appears as a three-dimensional object floating in the air.
But the fundamental problem was that the diffuser used is usually rigid. This means that a hand touching the volumetric display could hurt itself or damage the device. This is where the Spanish team's crucial innovation comes in: the use of elastic materials for the diffuser.
Elastic materials deform and require image correction.
This was the main obstacle to overcome. The solution? A system that predicts what the image would look like if the diffuser were not elastic, and adjusts the future oscillations of the elastic diffuser to accommodate the manipulation. The result is surprising: a virtual object that can be manipulated naturally.
Natural and intuitive manipulation
Imagine holding a virtual cube between your index finger and thumb, rotating and moving it as you wish, or simulating legs walking on a surface using your index and ring fingers. These are the interactions made possible by this revolutionary technology, and what makes it truly special is the naturalness of the experience.
It makes me wonder how transformative this technology could be in areas like education. As the research team explains: “Displays such as screens and mobile devices are present in our lives for work, learning, or entertainment. Having three-dimensional graphics that can be directly manipulated has applications in education: for example, visualizing and assembling the parts of an engine.”
Another significant advantage is the possibility of collaborative interaction: multiple users can interact simultaneously with the same holographic content without the need for virtual reality viewers. This opens up particularly interesting scenarios for museums and exhibitions, where visitors can simply approach and interact with the exhibited content thanks to touch holograms.
Touch Holograms, Future Implications and (Obvious) Limitations
Touch holograms are a decisive step towards a more natural interaction with the digital world. We are at a turning point where this technology begins to adapt to our natural ways of interacting, rather than forcing us to adapt to artificial interfaces.
However, there are still issues to be resolved. The resolution and brightness of current prototypes probably do not yet match cinematic representations. There is also the question of scalability: how large can these touch holograms become? For now, we are probably limited to relatively small objects.
I also wonder how this technology will integrate with other emerging innovations such as artificial intelligence. Could we imagine AI assistants that not only answer our questions, but physically appear before us and can be “touched”? Despite these open questions, the importance of this technological breakthrough cannot be underestimated. The research team atUPNA, composed of Inigo Ezcurdia, Iosune Sarasate, Unai Fernandez, Elodie Bouzbib, Asier March e Iván Fernández, has taken a fundamental step towards a future where the line between digital and physical will become increasingly blurred.
The window between imagination and reality is closing rapidly, and perhaps the future we imagined in the movies is closer than we think. This time, however, we can actually touch it with our hands.
