One step on from virtual reality, augmented reality takes the real world and digitally distorts and transforms what we see around us. David Reid takes a trip to the Swiss City of Basel to experience it.
Basel, with the Rhine running through it, has long been a lure for tourists.
Seeing is believing: David Reid experiences visual high-jinks
But there is a potential new feature on the sightseeing map, which could help tourists better explore the town.
LifeClipper, a project created by new media organisation Plug.In, gives artists the digital tools to prise open the doors of perception.
The augmented reality system is entirely put together with off-the-shelf components.
A head-mounted camera, for instance, acts as the eyes.
As the subject makes his or her way around the tour, global positioning satellites help trigger visual high-jinks in the rucksack computer according to whichever zone the subject has wandered into.
Nikki Neecke, a sound-designer and musician for LifeClipper, says: "We have developed different scenes of picture sets and music, and we use the GPS to determine where we are in the street.
"So if I go to the border of the Rhine it is different from when I go to the church, and that's done using GPS."
It sounds straightforward enough. So I decided to give it a go.
The first difficulty was simply getting used to a robot's eye-view of the world, with low resolution and cramped field of view.
It is very, very difficult to walk with the apparatus on because there is a very slight delay between your actions and what you see through your eyes.
When I walked past a paper mill I could see the inner workings, and hear the sound of the mechanics thumping in my ears.
In 1943 Doctor Albert Hoffman invented LSD in Basel, and there is an amazing section of the tour that plunges the user into full-blown psychedelia.
However, a slight shift in reality is often more powerful than a massive one.
Jan Torpus, new media artist for LifeClipper, says: "We are not trying to develop a new technology here.
"We are trying to find a language for this new technology. That's an important part."
Plug.In's Annette Schindler adds: "It kind of materialises our imagination, something that happens in our head, also without the head-set and the computer on our back."
Seeing may be believing, but turn the world on its head and there is only so much we will find convincing.
By making subtle changes to what we see, augmented reality often goes one better than virtual reality.
And when it comes to playing tricks with our senses, the devil is often in the detail, as Jan Torpus explains.
"It has been said pretty often that the little changes - which make you think: 'what was that? Was it real or not?' - are much stronger than if you make an MTV show out of it."
The creators of LifeClipper see it more as an open-air art project than a new technology.
Many who have done the tour say it is like living a movie.
Jan and Nikki, however, are not so interested in Hollywood-style rags-to-riches and commercially exploiting their system.
They would prefer to take their equipment to other venues and develop new dimensions to their walking experience.
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