The “phone optical illusion” refers to a type of illusion where a 2D image can appear to be a 3D object under certain viewing conditions. The classic example is an image of a phone that appears to pop out from the page when viewed from a certain angle. This illusion takes advantage of the way our visual system interprets perspective and depth cues.
The key questions around this optical illusion are:
– What exactly creates the 3D effect?
– What types of images can be used to make this illusion work?
– Where and how can the illusion be seen?
What Creates the 3D Effect?
The phone optical illusion works because of how our eyes and brains interpret visual information. There are a few key factors that come together to create the convincing 3D effect:
The image is drawn using perspective – with converging lines and shrinking sizes – to give the impression of depth on a 2D surface. This makes it seem like the phone is receding away in space rather than lying flat.
Shadows and shading make some parts of the image appear closer than others. The shadows create the illusion that parts of the phone are curved or angled away from the background.
Some of the edges of the phone are hidden from view. This makes our brain “fill in” that it is a 3D object with invisible edges and sides.
When viewed from the right angle, each eye sees a slightly different image. This binocular disparity tricks the brain into merging the two views and perceiving depth.
So in summary, the combination of monocular depth cues (perspective, shading) and stereoscopic 3D effects makes our brain interpret the 2D drawing as a 3D object.
Types of Images That Work
Many types of images and scenes can be drawn to create this “pop out” optical illusion:
Small objects with clear edges and sides work very well. Classic examples are phones, books, boxes, clocks. The more defined sides the object has, the stronger the 3D effect.
Scenes with converging lines forming hallways or rooms are also effective illusions. The receding perspective leads to a strong sense of depth. Doorways and alcoves can “pop out” convincingly.
Interestingly, rows of receding text can also create depth and 3D effects from the right angle. The shrinking font size makes it seem like the text is extending away into the distance.
Side profiles of faces or heads, when drawn with the right shading and perspective, can also produce startling 3D illusions. This makes it seem as if the head is turning towards the viewer.
So in general, any object or scene that can be drawn with perspective and shading can produce this “pop out” optical illusion. The key is conveying depth and concealed edges on a 2D surface.
Where and How to View the Illusion
To experience the phone optical illusion, some key viewing considerations are:
You need to view the image from the intended angle, often around 20-30 degrees offset from the image surface. This allows each eye to see a slightly different perspective. Too straight-on or sharp an angle won’t create the 3D effect.
The illusion works best from a reasonable distance away, such as arm’s length. Being too close won’t let your eyes merge the two different views into depth. But too far reduces the stereoscopic effect.
The image should be evenly lit to fully perceive the shading and shadows. Overhead lighting or natural daylight works best. Glare or strong side lighting can obscure the depth cues.
The optical illusion can be produced on paper prints, screens, posters, books, etc. Smooth, non-reflective surfaces allow the image details to be seen most clearly. Glossy screens can create unwanted glare.
Subtly moving your head or shifting your body side-to-side helps reinforce the 3D effect. The image seems to shift and transform as both eyes obtain new perspectives.
So with the right set up and viewing, these monocular and stereoscopic depth cues combine to produce a very convincing phone popping out in 3D!
Notable Examples and Creators
Some pioneering and noteworthy versions of the phone optical illusion include:
Scott Kim is an artist renowned for his optical illusion drawings and perspective-based images. In 1976, he created an early example of the protruding phone illusion.
Mathematician Jerry Andrus produced influential optical illusions using dramatic perspective to make objects seem to pop out from the page. His creations included startling 3D phone and book drawings.
The Japanese psychologist Akiyoshi Kitaoka has generated many innovative optical illusions by combining perspective, shading, and color contrast. His distortions of 3D books are particularly striking.
Sugihara is a Japanese engineer who builds physical 3D models of mathematically impossible objects that seem to defy physical laws. His constructions include projecting mobiles phones that appear to levitate in mid-air.
“Is This an Illusion?” Exhibit
A 2015 art exhibit in Belgium titled “Is This an Illusion?” featured many iterations of the protruding phone optical illusion. Various artists and designers offered their own creative twists showcasing depth and perspective.
So while seemingly simple, the popping phone has inspired many visionaries and continues to reveal secrets of human visual perception.
The Math and Geometry Behind the Optical Illusion
The phone optical illusion takes advantage of some key mathematical and geometrical principles:
Parallel edges of the phone are drawn shorter to create the illusion of receding away in space. This foreshortening makes objects appear compressed along the line of sight.
Converging parallel lines give the impression of extending back to a vanishing point on the horizon. This defines the focal perspective.
Each eye views the slightly shifted image from a different horizontal angle. This binocular disparity helps our brain merge the two views and judge depth and distance.
The curved surfaces of the phone may be drawn using ellipses and parabolas. These conic sections represent slices through 3D cones, helping create rounded forms.
Our perceived visual space differs from flat Euclidean geometry. Curved shapes are interpreted as 3D objects bending away in space rather than 2D curves on a plane.
So the carefully constructed geometry generates contradictory depth cues that trick our visual system into seeing 3D structures on a 2D surface.
Beyond artistic optical illusions, manipulating depth perception has many practical applications:
Stereoscopes and 3D displays
The principles behind protruding phone illusions are used in VR headsets, 3D movies, holograms, and other technologies to immerse viewers in artificial 3D worlds.
Medical and scientific imaging
Advanced 3D rendering and surface shading can provide surgeons and researchers clearer visualizations from MRI, CT, and microscopy data.
Computer graphics and animation
CGI artists use tools like foreshortening, lighting, motion parallax and occlusions to integrate computer-generated objects into live-action footage.
Camouflage and concealment
Military camouflage uses “dazzle” patterns with dark and light tones to obscure depth, size, shape and movement. This disguises people, vehicles and facilities.
Architecture and design
Creative use of perspective, spacing, lighting and materials can produce spaces and interiors with compelling depth, proportions and functionality.
So while deceiving our visual system for artistic effect, these illusionist techniques have found widespread utility in recreating the look and feel of 3D worlds.
Limitations and Controversies
Despite their convincing depth effects, protruding phone illusions have some detractors and limitations:
Short viewing duration
The 3D effect only lasts for brief periods before the brain “sees through” the trick and perceives it as flat again. Constant head movement helps sustain the illusion.
Narrow viewing angle
The optimal 3D view only appears from specific angles. Step a few degrees left or right, and the effect collapses back into 2D. This makes the illusion fragile.
Placing protruding phone art on floors or sidewalks has led to pedestrians injured by running into the art while distracted by the perceived depth.
The simple shading tricks provide only crude depth approximations compared to advanced 3D displays and holodecks. Some find the illusions unconvincing.
The blurring between 2D and 3D can be disorienting. The brain strains to constantly reassess the visual input as either flat or deep.
So while thought-provoking, these optical tricks can’t fully duplicate natural depth perception. The illusion remains limited and ephemeral.
The protruding phone optical illusion offers a fascinating look into the complexities of human vision. While seeming to transcend the limits of a 2D surface, this visual deception relies on basic perceptual shortcuts in our visual processing. The precise angles, shading, and geometry manipulate monocular and stereoscopic depth cues to conjure 3D structures from 2D images for brief moments. But it takes our imaginative visual system to fully complete the illusion and transport simple drawings into intricate artificial worlds. While limited compared to virtual reality or holograms, these clever 2D illusions reveal how little reality our eyes actually see, and how much our minds fill in. The protruding phone not only creates illusion, but reveals truth about perception’s inner workings.