'Inversion' is a powerful optical illusion which suggests that, when an edited image of a face is seen upside down next to the original, both will look the same. Place both pictures the right way up, though, and the edited image will stand out like a sore thumb.
According to a study by Sainsbury Wellcome Centre: "Our perception of human faces most likely consists of two distinct processes. The first is local processing of individual facial features such as the mouth, nose, and eyes. The second is global processing of the relationship between these features. These processes are incredibly sensitive and effective, but seem to struggle when faces are seen upside down."
The theory was tested out in a 1980 by Peter Thompson with the 'The Thatcher illusion' and is now a widely published paper.
When the two images are viewed upside down, they appear to look similar at first glance but, when viewed the correct way, you can clearly see the difference between the two images (see the sliding image below).
So we thought we'd give the process a try and the results are incredible.
Queen Elizabeth II
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