Shorter and Shorter / Higher and Higher

Made by Jessica Liu, Cloud Tian and Fred Qiao

Everlasting illusion!!!!

Created: October 20th, 2015


Curatorial Statement

The main goal of this project is to show the Muller Lyer illusion using video and sound: the visual part enhance the experience with the audio illusion while the audio part provide a more concrete experience of the visual part. We animated the "arrows" so that they seem to be shrinking while moving upward.  In order to deepen the experience of the illusion, we made a Shepard tone that the pitch of the tone seems to be moving upward forever. 



 We created a video with a sequence of arrows moving upward while changing the directions that they are pointing at. We used Python and Adobe Premiere to create our product. Here's our final outcome:


Perceptual Illusion

We selected the Muller Illusion as our main topic of the project. Basically, Muller Illusion consists of s set of arrow-like figures with fins pointing inward or outward. Although the straight line segments are of the same length, people tend to think that the arrow with fins pointing inward is longer. This s because our visual system judge the depth and distance of things we see constantly. Our subconscious  makes us to believe that line with fins pointing inward is farther away and therefore longer. 


Another perceptual illusion we use is the Shepard tone (also called the Shepard scale). The Shepard tone trick listeners to believe that the tone is continually ascending in pitch, although in fact the tone does not get any higher. This illusion is achieved by combining a higher tone and a lower tone into one. When the pitch goes up, the lower tone becomes louder and louder and eventually superimpose the higher one. Therefore the overall pitch of the tone seems to be going upward forever. 



We were inspired by the Muller Lyer Illusion as well as the Jastrow Illusion, specifically these two images from last week's assignment Ignis fatuus. 


Since our final video should be loop-able, Cloud suggested that we could either show something moving in a circle or something moving constantly upward(or downward). For these two images, it's a lot more reasonable to make them move vertically.



We first came up with the idea of the Shepard tone. And the fact that the pitch of a Shepard tone is constantly going upward lets us think about making a sequence go images moving up. First we considered using the image of the mug, however a moving mug does not really qualify as "poetic" or "beautiful". Thus, we reconsidered and decided to use the Muller Lyer illusion, which was actually the topic of Fred's last project. 

For the visual part, we first tried to use Photoshop, which turned out to be more complicated than expected. So we changed to use Python. We were afraid that the "shrinking" effect won't be too obvious since the straight lines are close to each others and a viewer can easily compare the lengths. Fortunately it worked in the way that the lines do look like shrinking. Finally we made little adjustments to make it simple but still elegant. To illustrate the effect online, we used quickTime player to take screen video and then add sounds on it.

For the sound part, we searched on the Internet on how to construct a Shepard tone. We tried several times to construct one on our own but all failed. So we took several video/sound trek from youtube and used Adobe Premiere to chop off the sound and adjust it to more properly fit our need. 



We are quite satisfied with our final outcome. It is beautiful because of its simplicity and continuity. We definitely achieved our goal to trick the viewers to believe that the arrows are shrinking in length while the pitch of the tone is going upgrade forever. This video can be played forever. There is a minor issue: while the visual part (the arrows) is moving smoothly, the sound trek is not. Other than this, we think we've created a interesting and poetic piece of work. 



The three of us collaborated well on this project. It's harder than we thought to turn a illusion into video motion though. And in order to achieve the effects we want, we had to made tons of adjustments. Through this project, we get to explore more the general concept behind  the Muller Lyer illusion and learn how to utilize what we learn to build our own preceptorial illusion.  

Actually, it's quite interesting to combine images and audio because before I didn't expect that the effect of combination is not just to add them together. If we choose audio and video with similar effects properly, we can have much stronger effect on people because our brain does not process images and sounds separately. Instead, we sense things using sounds and images together. 


7 comments · Latest by Lucy Tan

Wow, this is pretty neat. A great take on the Muller Lyer illusion. The combination with the Shepard Tone really helps it. It looks kind of like an ascending ladder. It would be kind of cool to have some kind of object "moving" on top of it, perpetually sliding down the stairs.

I noticed that you said it was difficult for you to create a Shepard Tone from scratch. I don't doubt this, but there are several resources online which can create one for you without you having to cut up Youtube video soundtracks.
This thread has a Shepard Tone plugin for Audacity, a free audio editor. You would also probably be able to customize the tone's speed to match your animation.

I think the only problem really with the end product is that it's not quite a perfect loop. Although the initial part was cool, it does prevent it from being a loopable gif/video. Maybe if you had an ending with the bars sliding all the way across the screen, or forwent the initial climb?

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Everlasting illusion!!!!