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Chunder thunder: The optical illusion that’s gripping the nation

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Published on 18 December 2019

UoS academics' optical illusion Chunder Thunder
UoS academics' optical illusion Chunder Thunder

Two University of Sunderland academics are causing a splash with an optical illusion.

Dr Mike Pickard and Gurpreet Singh were finalist in this year's international visual science competition Best Illusionist of the Year.

Their illusion, 'Chunder Thunder', is a painting of an old sailing ship in stormy seas that seemingly comes to life - but infact uses minute changes in perspective to give the illusion of movement.

Its description on the competition website explains: “In this illusion, the 17th Dutch marine artist Ludolf Bakhuizen’s painting “Ships on a Stormy Sea” is seemingly bought to life.

“The ship appears to be tossed around on a raging sea in a wild storm where the waves surge past and the clouds scud across the sky.

"With the hatches battened down, the crew are experiencing a roller coaster ride! However, this impression of wild motion is illusory.”

To develop the illusion, the Sunderland academics moved all the elements of the painting forwards by a tiny amount and then back by the same amount.

However, that by itself would only make the image flicker, and wouldn’t create the illusion of movement.

Instead, the addition of dark and light flashes makes the boat appear to lurch back and forth in the water.

The researchers explained: “The directional motion seen in this illusion is achieved using positive and negative images and different luminance levels.

“Visually, this favours the forward motions seen so that an overall impression of continuous motion is created.”

The Best Illusion of the Year Contest, hosted by the Neural Correlate Society, is now an annual online event.

Gurpeet Singh, the Principal Lecturer and team Leader for Design at the University, and Dr Mike Pickard are researching the link between visual science knowledge and art and design practice.