Shape from motion only

2017 First prize
Hedva Spitzer, Dana Tearosh, Niv Weisman: “Shape from motion only”. School of Electrical Engineering. The Iby and Aladar Fleischman Faculty of Engineering. Tel Aviv University. Israel

Author description: The phenomenon “Shape from Motion Only” presented in its purest form in the video i.e., the information is only in the temporal domain, without any clues in the spatial domain. Both the object and the background are created by flashing the pixels on and off, while the only difference is expressed in the temporal properties. We examined various properties of the phenomenon such as: statistics and object size. Furthermore, we examined how several known optical illusions like “Rubin’s Vase” might occur using this temporal phenomenon. This research has the potential to open a hatch for better understanding the visual system mechanisms.

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Skye Blue Café Wall Illusion

2017 Second prize
Victoria Skye: “Skye Blue Café Wall Illusion ”. USA

Author description: Do the dark blue rows appear to slant? Surprise! They are completely straight and in parallel rows. The rows appear to skew due to the contrasts and variants in light and color as well as the varying angles of the diamond targets at the intersections. Blurring the image dissipates the illusion by dissolving the contrasts and angles. The Skye Blue Café Wall is an adaption of previously discovered versions. Richard Gregory made the original illusion design famous after documenting the illusion seen on a café wall in Bristol England. Professor Akiyoshi Kitaoka has created multiple versions of the illusion that include the contrasting targets.

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Dynamic Müller-Lyer Illusion

2017 Third prize
Gianni A. Sarcone: “Dynamic Müller-Lyer Illusion”. Archimedes Laboratory Project. Italy

Author description: Müller-Lyer’s illusion proves that a segment can visually appear longer or shorter depending on the sense of the arrow heads at its ends. As shown in the animation, the red dot in the middle of the line is equidistant from the other two red dots, although the ends of the line visually appear to alternately stretch and shrink like a rubber band! The radial version of the illusion is even more impressive: The perceptual increasing and decreasing of the segments occurs in a very short time. Thus, I suppose it is more a physiological phenomenon, rather than a psychological bias. Our attention seems to be attracted by the receptive field WITHIN the V-shaped arrow heads, causing an illusory inward or outward shift of the ends of the line.

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TILLA at the beach

– Joel Ydring: “ TILLA at the beach”. Sweden

Author description: When my daughter Tilla practiced writing her name in the sand I looked for a fun way of capturing the moment. I found that the long depth of field of a mobile phone camera was perfect for making an illusive perspective. A simple panning makes the letter installation reveal itself as the subject makes her way through it, creating an interesting play with size, distance and the joy of learning.

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Partial Disappearance Illusion

– Kokichi Sugihara: “Partial Disappearance Illusion”. Meiji University. Japan

Author description: There are three objects that look identical, but when we reflect them in the mirrors, different parts disappear. For the first object the rooster at the bottom disappears, for the second object the upper half of the structure disappears, and for the third object the lower half disappears. They all come from the height-reversal property of horizontal pictures; when we interpret a horizontal picture as a 3D object, the perceived height is reversed in the mirror. In fact the three objects are a mixture of 3D structures and 2D pictures, and the 2D pictures create unusual visual effects.

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The Windmills of your Mind Illusion

– Michael Pickard and Gurpreet Singh: “The Windmills of your Mind Illusion”. The University of Sunderland. UK

Author description: How is it possible to see simultaneous forward and backwards rotation in the windmill when it is turning at constant speed and direction? Key factors in this illusion include: symmetry in the windmill design; the amount of rotation per frame; persistence of vision; and the propensity in vision to group together things that are in close proximity. The schematics provided show how differences in pitch together with the careful positioning of the windmill arms determines how visual groupings can be formed one way or the other and it is these that determine the direction of motion seen.

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The Mask Induced Filling-out

– Shuichiro Taya: “The Mask Induced Filling-out”. Hiyoshi Psychology Laboratory, Keio University. Japan

Author description: In the presentation video, a line circle (‘mask’) and a textured circle (‘disk’) are alternately displayed in successive short time intervals. However, if one keeps their eyes fixed on the central red cross, the texture inside the ‘disk’ appears to have subjectively spread out and cover the entire display. This appearance of illusory texture is quite clear. Under the ideal case, one cannot distinguish whether the peripheral texture is an illusion created by one’s brain or if it physically present for real.

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The Material Inversion Effect

– Juno Kim and Phillip J Marlow: “The Material Inversion Effect”. University of New South Wales, UNSW Sydney and Sydney University. Australia

Author description: In this effect, we show that the same image can appear to depict an object constructed from either an opaque shiny material (like polished metal) or a transparent refractive material (like solid glass). The appearance of glass or metal depends on whether the image is presented upright or inverted. This illusion reveals that our brain visually infers the material properties of objects from images using knowledge about how prevailing illumination interacts with the optics underlying refractive and reflective materials.

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The Shrink and Swell Illusion

– David Phillips and Priscilla Heard: “The Shrink and Swell Illusion”. University of the West of England. UK

Author description: The illusion is that the objectively static sides of a V-shaped window appear either to expand or to contract horizontally. Portraits within the window, expanded at the top and squashed at the bottom into the V-shape, rise or fall at constant speed. The illusion may arise because the V-shape of the window presents powerful linear perspective, suggesting depth, whereas the moving patterns within it only indicate change in size, and look flat. Illusion vanishes if this “optic flow” within the window moves not only with horizontal shrinkage and expansion, but also with vertical acceleration, typical of movement in depth.

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Complementary Afterimage ( Quantum Rainbow )

– John Post: “Complementary Afterimage ( Quantum Rainbow )”. Belgium

Author description: Colors can cancel each other out in different ways, one way is to observe an almost full color spectrum in a rainbow. It’s since ancient history debated whether a rainbow is caused by waves or also quantum physics.

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