This illustration demonstrates the set-up of the Metrovision system. Image courtesy of Optek S.A.

Persistence of vision is the phenomenon that enables us to see motion pictures--a rapid succession of still frames--as a continuous reality. Cinema has been designed on this phenomenon, and we have constructed the idea of a cinematic experience being one in which we, the viewer, sit still while images pass before our eyes.

What If?
What if we were to keep the images still and move the people instead? This is the thought that motivated a group of engineers, artists and scientists in Santiago, Chile, to develop a system that literally reverses the cinematic experience as we know it. Enrique Vial, a civil engineer with the Catholic University of Chile, and Dr. Miguel Lagos, a physicist with the University of Chile, formed a company called Optek S.A. in 1993, sharing space with Vial's animation studio, Cineanimadores S.A. Five years later, they have patented "Metrovision," a system which enables passengers on a moving train to view animation as they pass through tunnels.

Close-up of a lenticular panel. Image courtesy of Optek S.A.

But How?
The Metrovision system utilizes many of the same optics principles discovered by pioneers in the 19th century who developed optical toys such as zoetropes and phenakistoscopes. Metrovision, in fact, could be described as a sort of "human zoetrope." As the train moves, it passes a series of still images outside, at the passengers' eye level.

Vial explains: "On the tunnel walls we place panels, approximately 900mm long by 600mm high and 100 mm deep. The clarity of the animated images depend on the train speed; 30 Km per hour up to 60 Km per hour averages 10 to 20 meters or panels per second."

What may seem like a simple idea actually took years of research, development and testing. "We can positively say that ours is not a trivial solution. There are others that have worked in similar areas, but their solutions have not yet been practical in regards to both the physical phenomena and economic feasibility," said Vial. He added, "We believe that this project would not have been possible ten years ago," citing that recent advances in computerized, numerically controlled machines, computational software, techniques for graphic applications and the development of new optical plastics materials were of capital importance for the success of Metrovision.