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Jean Pierre Charalambos
Universidad Nacional de Colombia
Presentation best seen online
See also the source code
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- History of Linear Perspective
- Depth Perception
- Optical Illusions
- Final thoughts
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- (Classical) Emission theory vs Intromission theory
- Unconscious inference (Hermann von Helmholtz):
- light comes from above
- objects are normally not view from below
- faces are seen (and recognized) upright
- closer objects can block the view of more distant objects
Visual (cognitive) illusions (inference process failure) -> visual system assumptions insight
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Scintillating gridV:
Note that the scintillating grid code is:
function setup() {
var myCanvas = createCanvas(400, 400);
myCanvas.parent('scintillating_id');
strokeWeight(3); // medium weight lines
smooth(); // antialias lines
stroke(100, 100, 100); // dark grey colour for lines
noLoop();
}
function draw() {
background(0); // black background
var step = 25; // grid spacing
//vertical lines
for (var x = step; x < width; x = x + step) {
line(x, 0, x, height);
}
//horizontal lines
for (var y = step; y < height; y = y + step) {
line(0, y, width, y);
}
// Circles
ellipseMode(CENTER);
stroke(255, 255, 255); // white circles
for (var i = step; i < width -5; i = i + step) {
for (var j = step; j < height -15; j = j + step) {
strokeWeight(6);
point(i, j);
strokeWeight(3);
}
}
}V:
Hacking instructions (setup and run) found here
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Cafe-WallV:
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Zollner ilussionV:
Muller-LyerV:
[Poggendorff Illusion](https://en.wikipedia.org/wiki/Poggendorff_illusion)V:
Ponzo illusionV:
[Penrose Triangle](https://en.wikipedia.org/wiki/Penrose_triangle)V:
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Motion BindingV:
Stuart Anstis ilussionV:
[Illusory Square](https://www.geek.com/news/10-astonishing-optical-illusion-gifs-1575117/)V:
Ebbinghaus illusionV:
Lilac Chaser IllusionN: Combination of:
- Phi phenomenon: is the optical illusion of perceiving continuous motion between separate objects viewed rapidly in succession
- Afterimages
- Troxler's fading: When a blurry stimulus is presented to a region of the visual field away from where we are fixating, and we keep our eyes still, that stimulus will disappear even though it is still physically presented
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CheckerV:
Stroboscopic MotionV:
Rotate Square MotionV:
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These results can be explained by a psychological study providing evidence for a viewing-from-above bias that influences observers' perceptions of the silhouette. The results indicated that there was no clockwise bias, but rather viewing-from-above bias
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Pinna ilussionV:
Silencing IllusionV:
Wagon Wheel IllusionH:
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Visual masking describes the perceptual phenomenon that the presence of one visual pattern can affect the visibility of another pattern [FSPG97, KB05].
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Problem: is it that "accurate perceptions are fitter perceptions" the right intepretation of evolutionary theory?
Methodology: evolutionary game simulations between competing organisms some of which perceive (part-of) reality as it is and some which see only fitness
Results: evolution doesn't favor veridical perceptions (they go extinct)
Conclusion: (in contrast) we re-construct what we see, because it's useful (in evolutionary terms)
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- Visual illusions: suggest we construct what we see
- Evolutionary theory deals with: what does natural selection favors?
- Methodology: uses evolutionary equation. Key notion fitness = f(reality-as-it-is, organism, state & action)
- Conclusion: "we re-construct what it see": whatever it is. Two theories:
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