Optičke iluzije
Optičke iluzije su „krivo“ percipirane pojave koje često mogu biti zbunjujuće. One su najčešće i uključuju samo pojave koje percipiraju oči za razliku od perceptivnih koje uključuju sve pojave koje opažamo na bilo koji način. Uzrokovane su nesavršenošću naših čula, a neke radom našeg mozga. Mozak prima informacije od receptora u oku, ali zapravo, oko prima samo određenu količinu vizuelnih informacija u svakom trenutku, dok ih naš mozak neprekidno dešifruje, konstruiše i rekonstruiše, dajući nam iluziju kontinuiranog prizora.
Umetnici kao što su Moris Ešer su dugo koristili iluzije u umetnosti, kreirajući slike koje su vizualno intrigantne podjednako koliko i umetnički, stimulišući u isto vreme i um i oči. Drugi umetnici koji su stvarali remek-dela sa optičkim iluzijama su između ostalog Salvador Dali, Rafaelo Santi i Žorž-Pjer Sera. Grčki filozofi su bili jedni od prvih koji su pokušali objasniti fenomen optičkih iluzija. Epikur je smatrao da um vidi i čuje, a da su sva ostala čula zapravo slepa i gluva. Postoji mnogo vrsta varki, od takozvanih pa-slika u koje se morate dobro zagledati, preko pogrešne percepcije linija, oblika i boja, do sitnih, zbunjujućih kompjuterskih animacija. Danas one služe za zabavu, koriste se u umetnosti, muzici, medicini i tako dalje.

Tipovi iluzija:
1. Nemoguće optičke iluzije – švedski umetnik Oskar Reutersvard je 1934. prvi kreirao nemogući trougao od kocki. Od tog trenutka mnogi umetnici stvaraju nemoguće optičke iluzije. 2. Trodimenzionalne optičke iluzije – vrsta iluzije kada su linije složene tako da izgleda kao da figura izlazi iz lista papira. Najčešći primer takve iluzije je crtež kocke pri čemu izgleda kao da je trodimenzionalna. 3. Kamuflaža – najčešći primer kamuflaže koriste životinje u prirodi. Radi se o iluziji prikrivanja i stapanja s okolinom. 4. Iluzije preslikavanja – ova vrsta iluzija uzrokuje da vidimo pokrete i boje tamo gde ne postoje. Primer takve vrste iluzija je kada sa sunca uđete u zamračenu prostoriju te vidite obrise stvari koje ste malopre gledali. Iako ti predmeti ne postoje u prostoriji, njihova slika nam se zadržava u očima još neko vreme. 5. Iluzije dvosmislenosti – takve iluzije u sebi sadrže dve ili više slika. Iako se možemo prebacivati s jedne slike na drugu, oko nam ne dozvoljava da ih vidimo obe u isto vreme. Jedna od najslavnijih slika takve vrste je iluzija mlade devojke/stare gospođe. Tačno poreklo ove iluzije se ne zna, ali se pojavila na anonimnoj nemačkoj poštanskoj markici 1888. 6. Iluzije iskrivljavanja, boje i senki – iluzije iskrivljavanja objekat čine drugačijim od onoga kakav zaista jeste. Pri tome se drugačijim čine njegova veličina i oblik.



Optical illusions

Optical illusions are “falsely” perceived images or appearances that can often be confusing. They are most common and they include only visually perceived images in contrast to perceptual illusions that include all things perceived in any possible way. They are either caused by imperfection of our senses, or work of our brain. The brain receives information from the receptors in the eye, but actually the eye receives only a portion of visual information in each moment, while our brain decrypts, construct and reconstructs them continuously, thus giving us an illusion of a continuous scene.

Artists such as Maurits Cornelis Escher have been using illusions in art for a long time, creating pictures that are as intriguing visually as artistically, stimulating both the mind and the eyes at the same time. Among other artists who used optical illusions to create masterpieces are Salvador Dali, Raffaello Santi and Georges-Pierre Seurat. Greek philosophers were the first who tried to explain the phenomenon of optical illusions.  Epicurus thought that mind could see and hear, and that all other senses are actually blind and deaf. There are many illusions, from so-called afterimages which continue to appear in one’s image after the original image has been looked at, then wrong perception of lines, shapes and colours, to tiny, confusing computer animations. They are used for fun, in art, music, medicine and other fields.

 

Types of illusions:

  1. Impossible optical illusions – Swedish artist Oscar Reutersvärd was the first who created impossible triangle composed of a series of cubes in 1934. Since then, there have been many artists who have created optical illusions. 2. Three-dimensional optical illusions – a kind of an illusion in which lines are composed in such a way that it looks as if a figure emerges out of a piece of paper. The most common example of such an illusion is a drawing of a cube that looks as if it were three-dimensional. 3. Camouflage – the most common example of camouflage is used by animals in nature. They use illusion to protect themselves by blending in with the environment. 4. Afterimages – this type of illusions makes us see movements and colours which do not exist. Examples of such an illusion are when, after being in a sun-lit space, you enter in a dark room and see the shape of things you have seen before. Although these object are not in the room, their image stays in our eyes for some time. 5. Ambiguous images – such illusions contain two or more different pictures. Although we can switch from one to another, our vision does not allow us to see both of them at the same time. One of the most famous such image is the illusion of a young girl / an old lady. We do not know the exact origin of this illusion, but it appeared in an anonymous German stamp in 1888. 6. Illusions of distortion, colours and shadows (perceptual organization) – such illusions make an object different from what it really is. Its size and shape look different.