Holograms, although they may seem like something too abstract and far from our traditional understanding, are actually closer than we’re used to think.
We all have a wallet in our pocket or purse and a credit card or identity card in it. Here, these cards are full of holograms, although many of you do not expect it.
Holograms are the tool through which we can break down the barrier between what is virtual and what is real.
Hologram technology is closely linked to augmented reality. Let’s take a look at some examples.
AUGMENTED REALITY AND HOLOGRAMS
Augmented reality (AR) is the reality we all experience on a daily basis, although enriched with digital information. In other words, it is an expansion of a person’s sensory perception and intellect. This is why it is called augmented reality, in the sense that it augments the reality we already experience by adding data in digital format, creating a sort of integration between real and virtual, but without ‘teleporting’ us into parallel realities.
But how is this reality implemented? Very often it’s through smartphones and downloadable apps that make use of the phone’s camera to show a view of the real world overlaid with text, visual information and 3D holograms.
A concrete example is ‘Pokémon Go’, a game that adds the image of small characters from the Pokémon franchise to the reality that can already be seen through the camera and the aim of the game is to catch them through the smartphone. Pokémon Go has been very successful, especially among young people, which is why it is commonly believed that augmented reality was created for entertainment purposes only. In reality, as well as focusing on the entertainment side, holograms and other augmented reality technologies are used also in the information and commerce industries.
There are many brands and companies that decide to use augmented reality. One of many is IKEA, which has integrated software into its mobile application that allows you to view all the products in its catalogue in your own home. A hologram of the Strandmon armchair can magically appear in your living room.
In addition to the use of smartphones, augmented reality can also be implemented through more sophisticated devices such as hi-tech wristbands for the remote control of electronic tools or used through smart glasses and head-mounted displays.
In essence, augmented reality adds multimedia content to our world and holograms are used to break down the barrier between what is real and what is virtual.
THE HOLOGRAM: HISTORY AND EVOLUTION
Holograms were born around the first half of the 1940s. Dennis Gabor, a famous Hungarian scientist, developed the theory of holography while working on improving the resolution of an electron microscope. He coined the term hologram, which comes from the combination of the two Greek words holos (whole) and gramma (message). Unfortunately, holograms were not very popular in the following years, due to the underdeveloped light sources of the time.
Finally, in the 1960s, the laser was invented, which was perfect for creating holograms thanks to its powerful flash of light that lasted only a few nanoseconds, effectively blocking movement, thus creating holograms of high-speed events or people. Notably, the first hologram of a person was created in 1967. This gave rise to pulsed holographic portraiture.
In 1962, two American scientists, in the wake of Gabor’s theory, decided to go further and use not only lasers but also a technique they had already implemented in their work on the development of side-reading radar. The result of all this was the creation of the first 3D moving holograms, namely a toy train and a bird.
Yet another development in the world of holograms was achieved in 1968 by Stephen A. Benton, who invented white light transmission holography, which makes it possible to create a ‘rainbow’ image from the seven colours that make up white light. Benton’s invention is important because it made it possible to mass-produce holograms using an embossing technique.
Today, the tools needed to create 3D holograms (a continuous wave laser, optical devices such as lenses or mirrors to direct the laser light, a film holder and an insulating table on which the exposures are made) are common in many laboratories and studios.
WHAT IS A HOLOGRAM
A hologram can be defined as a recording on a photographic plate or film that results from the division of a laser beam into two separate beams, one from the object and one from reflection, using an angled mirror. The first ray is reflected and thus creates the image of the hologram on the so-called holographic plate, which is precisely the end surface, while the reflection ray is directed onto the plate. The moment these two rays come together the hologram is created.
In essence, the hologram allows the reproduction of an image that is previously recorded. The recording phase consists precisely in the moment when the division of the laser beam into two beams takes place. Thanks to an interplay of mirrors, the light from the source interferes with the light reflected from the object, forming two lines on the plate which are called ‘interference fringes’. These contain the information that allows the three-dimensional image of the object in question to be reconstructed and decoded as if it were physically present. Holographic technologies, in a way, transform light into matter.
Engineers, architects or doctors also make use of holograms in order to have a more ‘practical’ and direct experience than what they have only ever read in books. For example, there are so-called ‘medical holograms’ that refer precisely to 3D reconstructions of the organs concerned. Obviously, only a few hospitals can afford this technology at the moment because of the high costs.
From an economic point of view, it is interesting to note that the main investors in holography are, for a change, the USA. The aim of the world’s leading economy is to create more dynamic environments, interactive workstations, real and virtual objects in order to optimise interactions. While difficult is the accessibility of such technologies in territories of the world that do not have internet connections powerful enough to support modern cloud computing or resources to purchase devices.
THE MICROSOFT MESH CASE
Holograms have a connection not only with augmented reality, but also with mixed reality, as demonstrated in Microsoft’s Mesh presentation at Microsoft’s Ignite event in March 2021.
The platform in question, reads the company’s portal, is the result of years of research and development by the Redmond-based company in the areas of eye and hand tracking, HoloLens development for the creation of holograms and artificial intelligence models capable of creating expressive avatars.
This is a new mixed reality platform that Microsoft has built with the aim of facilitating and speeding up the creation of multi-user and multi-platform MR applications.
Through Mesh it is possible to physically share virtual spaces with other people despite being in distant environments, feel their presence through facial expressions, collaborate more easily or assist other people.
Alex Kipman, Technical Fellow at Microsoft, says that Mesh is a technology that combines the physical and virtual worlds.
In particular, the technology used by Mesh is defined as ‘Holoportation’, a combination of hologram and teleportation. In essence, 3D models of people are reconstructed in real time and anywhere in the world. Using special devices, such as HoloLens 2, one can then interact in 3D with other participants in the mixed reality session.
The Mesh software allows you to choose whether to project your own realistic image or to customise your avatar in any way.
The Mesh platform consists of three fundamental elements:
- multi-device support, for a more complete 3D experience;
- the 'Mesh developer platform', which includes services such as Azure Active Directory, with which only authorised users can securely access the mixed reality session, or the Microsoft Graph service, through which it becomes possible to manage connections without having to worry about the technical aspects of audio and video transmission;
- Mesh-enabled apps, such as the Microsoft Mesh app for HoloLens 2 and AltspaceVR, already presented at Ignite.
According to Microsoft, Mesh represents the solution to four main issues that usually arise in mixed reality:
- the transfer of high-fidelity 3D models into the file formats that companies use;
- the realistic representation of people in mixed reality requires a lot of resources, both in terms of money and time;
- it is complicated to maintain a stable hologram in places where several devices are used, and moreover lighting conditions change according to layouts, moments;
- synchronisation of actions and expressions in different geographically distributed spaces is difficult.
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