"The current wall is 2 x 4 metres and can stand in height or width. It is such a monumental image," said Dr Berka. He noted that the goal was to make the wall as narrow as possible, which posed a major technical challenge. "Originally, there was only going to be one projector inside, but we didn't have it for such a large painting. So we decided to put together an image from two projections," the scientist said. He described that the group chose projectors with a classical projection method. However, they had to cross their optical axes.
"The projector providing the right half image is therefore located in the left part of the cabinet. And as they cross each other, quite large deformations are created at that severe angle. And that was one of the main technical problems that my colleagues and I solved," the expert pointed out. He added that the development team thus had to transform the broken image into a solid form.
According to the scientist, the interactive wall also has several sensors - for motion detection, measuring the amount and intensity of the world and the distance of a person. It can also recognise selected gestures of visitors to the exhibition. It responds to whoever it "sees" best. The software solution that makes this possible is an added value of the wall, according to Dr. Berka.
"The basis is the so-called presentation package - the collected data about the presented content. In addition to this, metadata is added with information about which sensor to use for a given presentation. And what the response will be. The author of the package can therefore define what is triggered when the visitor does something. And the wall's response is determined by what the package author sets up at the time," explained Dr. Berka.
A choice of four options
"The mission of the projection wall in the ZeMě exhibition is to support or summarize the message of the individual presentation islands. It contains short, roughly 30-second videos," added Dr. Ondřej Táborský, co-author of the ZeMě exhibition, who works at the National Museum. "They are processed in the form of humorous sketches in which actor Petr Vacek and actress Veronika Čermák Macková refer to the islands. They end with playful word innovations - e.g. slow fashioner, adaptor, composter. We are satisfied with the wall and the content," described Dr. Táborský. He noted that its impact is only undermined by its placement in a corner due to lack of space.
Odborník také uvedl, že reakce na výstavu celkově byly během roku pozitivní. “A to jak od běžných návštěvníků, tak od odborné veřejnosti. Už samotný fakt zpracování aktuálního tématu v historické budově Národního muzea je pro mnohé překvapivý. Zvlášť oceňovaná je prezentační forma založená na kombinaci různorodých médií a interaktivit,” shrnul Táborský.
The expert also said that the reaction to the exhibition has generally been positive throughout the year. "Both from ordinary visitors and from the professional public. The very fact that a topical issue is being treated in the historic building of the National Museum is surprising to many. Especially appreciated is the presentation form based on a combination of various media and interactivities," Táborský summarized.
According to Dr. Berka, the team defined six data types for the wall and implemented four of them. "One of the types is an image gallery. Imagine this on a mobile phone - the gestures are similar, except you'll be waving your hand a bit more because it's a bigger device. Then there's a video that you can trigger with a gesture. And we sometimes set it up so that it only triggers itself when motion is detected," Dr. Berka described. The third type is a standalone 3D object that the user can manipulate. "And the fourth, and this is the main one, is a walk-through virtual scene. This can be created on various themes, for example by external collaborators of the museum and other memory institutions. It could be a paleontological landscape or other environments," said Dr. Berka. The technology, he said, allows people to navigate through predefined points as well as to propel the presentation with gestures.
The first wall was created as part of a three-year project that ended in 2022, but the team is now working on a second version of the wall, which includes a plinth - also interactive and running on the same software. "The plinth is designed to display content based on a technique called the Pepper ghost effect. Basically, you only see the reflection in the glass, not the glass itself. And he feels that he is observing the object in free space," Dr Berka noted. He recalled that this technique was already used in the late 19th century in theatres to create ghost figures. "An actor sat in the orchestra pit and the audience watched his reflection. Because he was partially transparent, he looked like a ghost. In our case, we use the possibility that some background can be installed behind the plinth, to light up the scene. We will see if the curators want to use this in the future," the expert stated, adding that the team is currently testing the use and effects of different lighting conditions.
"And another important thing - because the devices use the same software, there is a communication protocol designed between them so they can 'talk' to each other," Dr Berka pointed out. This way, he said, the author can set up a synchronisation of the presentation on both devices. "I can also put some places in the scene where the user activates an action with a gesture. And the reaction to this action will be that another part of the presentation will start on the other device," described Dr. Berka, adding that one system could theoretically use many more such walls that would present their parts from a single package - for example as a panorama. "So the interesting benefit we see is that it forms one coherent system. Two other pieces of software are also part of it. The first, contact manager, is used to prepare the presentation package. The second, exposition manager, allows you to create an exposition of these devices on your desktop."
In comparison with other similar projection tools for memory institutions, Dr. Berka said that such a comprehensive system is rather an exception. "There are also commercial variants, but they are more focused on tracking the visitor, how much time they spent in the exhibition and so on," the expert pointed out. Other techniques, he said, use, for example, virtual reality or a system of moving ice bulbs.
According to Dr. Berka, the current project is also related to the issue of long-term storage and archiving of various multimedia content. "In the Czech Republic, there are not yet very elaborate methodologies for these institutions. They mostly use the old ones, focused on physical objects - collections. And in our project we did not aim to solve this problem, but to open it up and try some experimental solutions," said Dr. Berka.
He added that the development team also addressed the implementation of part of the projection wall protocol into commercial technologies for remote control of multimedia systems used by the National Museum. "So far we're at the point where they can turn our technology on and off remotely. And still hanging in the air is the problem that the device should be able to tell on its own that it's in trouble. Like its projector isn't working. So the self-diagnostics still need to be fine-tuned," he concluded. Dr. Berka.
The ZeMě exhibition itself will be complemented in June by an accompanying thematic event for the general public. "On the occasion of International Environment Day, which will take place on 5 June, the National Museum in cooperation with CIRAA Advisory, Campus Hybernská, Kokoza and the UN Information Centre has prepared a day-long programme," said Dr. Táborský. "The morning will be devoted to lectures on sustainability and a tour of the ZeMe exhibition in the main building of the National Museum. The afternoon at the Hybernská Campus will focus on children's activities and lectures for adults," concluded the co-author of the exhibition.
Author of photographs: Petr Neugebauer