At some point you may have come across a photo or image of an optical illusion. It affects our unconscious a lot, as we often do not know what is happening for some time.
We call the illusions that deceive our visual system optical illusions. Illusion makes us see anything that is not present or it makes us see images in the wrong way.
The image of an object, transmitted by vision to the brain, is decoded and interpreted. However, under certain conditions, this interpretation can be wrong, as we have some difficulty in comparing angles, lengths and distances. This misinterpretation of what we see we call optical illusion.
Let's look at some examples:
Looking at the two straight segments in the figure below, at first glance we could conclude (wrongly) that they have different lengths. However, with the help of a ruler you will notice that they are congruent.
As for the figure below, we observe that the two segments GF and MN appear to have different lengths. Again, with the help of a ruler, you will see that they are congruent.
A deliberately drawn figure with errors in perspective can also lead to an optical illusion. In the figure below, a person descending the stairs would be at floor level. But, as the image was designed so that our eyes cannot unravel the mystery, we say that we are facing an optical illusion.
Relativity (1953), by M. Ç. Escher
By Domitiano Marques
Graduated in Physics
