Generales

By Carlos Olimpo Restrepo S, Journalist

The Optics and Photonics group was recognized by the 2023 Optica Foundation Challenge for its work on a project that goes beyond entertainment and telecommunications. This project aims to create more realistic holographic, virtual, and augmented reality experiences. The group is attached to UdeA's Faculty of Exact and Natural Sciences, and its laboratory is housed in the University Research Headquarters.

Since 2020, researcher and professor Alejandro Velez has collaborated with the Optics and Photonics group to develop a system that enhances the holographic experience. Photo: Communications Office / Alejandra Uribe

It's easy to trick the eye. It's easy to trick the eye. For centuries, audiences have been deceived by illusionists, magicians, and sorcerers. The entertainment industry has also tricked us into believing that we are witnessing things that are not real, such as a third dimension (3D), advertised in theaters, some televisions, or something more realistic, like holograms.

However, what you see in these systems are simply two-dimensional flat images that create the optical illusion that something is three-dimensional by showing slightly different views to each eye. These illusions are sometimes misidentified as holograms.

 "This is the case with holographic concerts, which feature deceased singers such as Michael Jackson. This works because those who organize the show can keep the audience in a specific location, giving them control over how each person perceives the scene; it is an optical illusion," said Alejandro Vélez Zea, professor at the Universidad de Antioquia's Institute of Physics.

Unlike these illusions, a real hologram is the complete record of all the information in a scene and requires optical systems that are difficult to find outside a laboratory. These holograms make it possible to reproduce a scene with all the real characteristics as perceived by our eyes, including 3D, according to the scientist.

Vélez holds a Ph.D. in physics and has been working since 2020 in the Optics and Photonics group, tied to UdeA’s Faculty of Exact and Natural Sciences, where he leads a project to make the holographic experience more lifelike and authentic by using a device different from the existing ones, for which he received the Reto Global Óptica award from the International Optica Foundation on October 10, and as a result, they will receive funds to continue with this initiative.

"This challenge is a call for young scientists and researchers from around the world, whose last academic degree was completed less than seven years ago, to propose innovative solutions to global challenges in three particular areas: information, medicine, and sustainability. The award is given to those who propose a novel, high-impact research initiative," said Vélez.

The scientist recalled that the screens of televisions, computers, mobile devices such as tablets and cell phones, and virtual reality helmets, which are used to watch movies, read books, or play games, among other things, are based on pixels, which are turned on and off to form still or moving images. These provide the appearance of depth.

"Another technology for modulating light is digital micro-mirror devices, which are systems of millions of micron-sized mirrors, one-tenth the size of a human hair, capable of rotating at very high speeds and, by doing so in an orderly fashion, allow light to take one shape or another," explained the researcher.

 "We've developed all the algorithms to take the virtual scenes, turn them into holographic scenes, project them onto the system, and see how they overlay in the real world." 

Alejandro Vélez Zea, Optics and Photonics Group. 

The research center

The research is being conducted on a large scale, but the goal is to create a portable device prototype in the near future. Photo: Communications Office/ Alejandra Uribe

Based on this, the Optics and Photonics group conducts research and experiments intending to develop a portable and individual device for real holographic visualization, rather than simulated, in the near future. 

"There are real holograms, such as those on ID cards, in other documents, and in some museums, which are plates of photosensitive materials that were exposed to laser light systems to record complete information about how the three-dimensional world can be perceived and therefore have the characteristic that, depending on the angle from which you look at it, you see one thing or another," recalled Alejandro Vélez Zea, who added that there are also holographic systems "based on the technology we use in cell phone screens, with modifications to be able to control the light much more precisely, and that is why they are much more expensive."

The researchers then focused on micro-mirror technology, which is used to project images on projectors and other equipment, because it is less expensive and can be used as a light modulator for holographic screens.

"We have already conducted laboratory tests, and the group has created several non-portable, lab bench prototypes in which we achieved augmented reality projection of holographic objects on real-world scenes. The limitation is that these devices are extremely bulky, and they are not optimized for portable devices. With the resources provided by this award of $100,000, we will be able to design a system to miniaturize, make it portable, and manufacture a prototype for an end user," said the researcher.

"The core of the proposal is to develop equipment that uses these devices to achieve holographic augmented reality at a much lower cost than what is available now. To do this, we have to implement the optical system, the computational algorithms that allow us to encode the scenes, convert them into content, and make all the necessary optimizations so that they can be used by people," he emphasized.

Simply put, the goal is to be able to create a helmet or glasses that superimpose a holographic, three-dimensional image transmitted from another location on the scene where the recipient is located, allowing him or her to deliver his or her image to the sender. In other words, augmented reality enables real-time telepresence in various parts of the world while remaining compatible with current telecommunications technology.

It would be similar to cell phone video calls: a user's equipment has a screen and cameras that capture the desired image (a person, an object), which is converted into information and sent through the Internet until it reaches another user who has a similar device.

"The difference is that in this system, the cameras must have the capacity to make a holographic record of information, a three-dimensional record of the scenes in which these devices are located, and instead of a conventional pixel screen, there is a holographic screen that reproduces the complete information of the scene captured by the camera," said the researcher Vélez Zea.

 The scientist pointed out that a blind person cannot enjoy this development, but thanks to the fact that this system requires total control of light, each holographic screen can be calibrated to correct visual impairments to instead deliver an unaltered image to people with certain visual problems, such as myopia.

 Beyond what has been achieved so far and what is projected for the foreseeable future, Alejandro Vélez Zea emphasized that "this research is completely autonomous, fully funded here, and it turned out to be something sufficiently novel for people to recognize and bet on it, as Optica Foundation did. This speaks highly of what is being done at the Universidad de Antioquia, as well as the ability of our research groups to conduct high-impact studies independently."