Wait, Look Again: Flat or Round? Real or Imaginary?

Posted on May 21st, 2019 by

Written by Grey Grettum, Amanda Otto, and Katie Velek

What is the anamorphosis illusion?

Imagine reaching for a baseball, but then realizing that the baseball you perceived is nothing more than just a piece of paper. As shown below, this is an example of the anamorphosis illusion. Anamorphosis is defined as “[the] use of the rules of linear perspective to create a two-dimensional image so distorted that it looks correct only when viewed from a special angle or with a mirror that counters the distortion” (Wolfe, 2018, p. 186). Watch and be amazed as this video seeks to demonstrate anamorphosis in a way to intrigue its audience, Ray Ban consumers.

https://petapixel.com/2013/10/12/two-minute-mind-bending-demonstration-perspective-anamorphosis/

What’s going on?

After being deceived, you may be wondering how this image of a distorted baseball betrayed you. When looking at the globe or baseball shown above, you are looking at it from a special angle which makes the globe/baseball look as real as you and me. As soon as you look at the object from another angle, it is distorted! So, how can we tell what is real or not in our everyday life? Luckily, you can obtain the knowledge to understand illusions, like anamorphosis.

There are several reasons why you are seeing anamorphosis, like various depth cues.  Depth cues are used to provide “three-dimensional depth in two-dimensional pictures”(Wolfe, 2017, pg. 179). One depth cue that could be helpful is to look at the size and position of the object(s). When the globe and baseball are not upright, they look extremely warped, this is because the artist is using the size and relative position of the object to create the 3D effect.

Second, linear perspective may also be helpful to recognize anamorphosis. Linear perspective is a “depth cue based on the fact that lines that are parallel in the three-dimensional world will appear to converge in a two-dimensional image” (Wolfe, 2017, pg. 184). When using linear perspective, you are able to determine the size of the actual object and understand background information which could help you steer clear of unreal objects or scenes. With these tips you can be more aware of our world.

Practical applications

An interesting application of anamorphosis is to get motorists to slow down while driving by creating 3D “crosswalk illusions” as shown below (Figures 2 and 3). There are several reasons why this illusion was created. First, the crosswalk illusion allows drivers to see the crosswalk more clearly which allows drivers enough time to slow down properly. Second, the crosswalk illusion tricks the drivers into believing there is something rising out of the ground that could hit their car. Both reasons allow the drivers enough time to properly slow down and avoid collisions. The hope with crosswalk illusions is to make crosswalks safer for pedestrians.

These sidewalks make both a powerful immediate effect and a minuscule lasting effect on the yielding of drivers. The effectiveness of adding the 3D component to already marked areas ranges from an additional 2.3% to 3.3% from the initial yielding percentages (Cambridge, 2012). However, the same study found minimal long term effects (max of 0.3% increase in effectiveness) and even found a drop in people yielding after the illusion was implemented (max of a 2% drop in effectiveness) (Cambridge, 2012). In other terms, there is a short term benefit, however long term there is harm. To see the overall statistics, refer to Figure 4.

Figure 2. Design of ‘Thunder’ 3D Pavement Illusion Marker.

Figure 3: Illustration of Phase 2:Pavement Marking Plus 3D Illusions
https://scholarworks.wmich.edu/masters_ theses/48

https://scholarworks.wmich.edu/masters_theses/48

Final Thoughts

Next time you start reaching for the baseball, that may or may not be real, try to utilize your skills of depth cues before succumbing to anamorphosis. Now that you have knowledge of anamorphosis, try playing fun tricks on your friend(s) to see if they succumb to anamorphosis. Or you can even invent new possible ways to improve safety in the world, hopefully having long-term effects. What is your favorite use of anamorphosis?

 

References

Cambridge, Nicole M., “Effects of Symbol Prompts and 3D Pavement Illusions on Motorist Yielding at Crosswalks” (2012).Master’s Theses. 48. https://scholarworks.wmich.edu/masters_theses/48

Wolfe, J. M., et al. (2017). Sensation & perception (5th ed.). New York, NY: Oxford University Press. ISBN: 9781605356419

 

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