Optical illusions
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The document discusses optical illusions and how they trick our perception. It introduces the topic and defines optical illusions as errors in how we perceive objects' shape, color, size or movement caused when the brain cannot interpret contradictory information from our eyes. Several famous illusions are mentioned like Mach bands and peripheral drift. The conclusion is that the closer you look, the less you see.
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Optical illusions
- 1. Optical illusions To see things from a different angle - Yougourta AIT SAADA 2018-2019
- 2. 2 01 INTRODUCTION 02 HOW DO WE GET TRICKED ? 03 SOME FAMOUS ILLUSIONS 04 CONCLUSION SUMMARY
- 3. 3 INTRODUCTION Optical illusions are errors in the perception of the shape, color, dimensions or movement of certain objects. They are easily identifiable by the multitude of information perceived by our eyes. If the information coming to the brain is contradictory, he can not interpret it.
- 4. 4 HOW DO WE GET TRICKED ? Object Sun Light Eye Light 1/10 second
- 5. 5 HOW DO WE GET TRICKED ?
- 6. 6 HOW DO WE GET TRICKED ?
- 7. 7 SOME FAMOUS ILLUSIONS Mach bands Peripheral drift
- 8. 8 CONCLUSION “The closer you look, the less you see”
- 9. REFERENCES • https://nei.nih.gov/kids/optical_illusions • https://en.wikipedia.org/wiki/Optical_illusion • https://www.amnh.org/explore/ology/brain/optical-illusions-and-how-they-work
Editor's Notes
- They Seeing is believing, right? Well, actually… What you see and what you think you see are different things.
- Optical illusions are errors in the perception of the shape, color, dimensions or movement of certain objects. They are easily identifiable by the multitude of information perceived by our eyes. If the information coming to the brain is contradictory, he can not interpret it.
- When you look at an object, what you actually see is the light, the light bounces off what we look at and penetrates our eye, so the light is converted into an electrical signal that our brain transforms into an image. This process lasts 1/10 th of a second. So at all times, our brain receives a tremendous amount of information and it's hard for him to try to focus on everything at the same time. But your brain does not simply receive this information—it creates your perception of the world. This means that sometimes your brain fills in gaps when there is incomplete information, or creates an image that isn’t even there! Why does this happen? Evolution! Survival depends on fast reactions. Your brain has evolved to work quickly to piece together whatever bits and fragments it can get—and to do its best to figure out the rest. An example is the illusion of Hering (and you make the slide appear).
- When you look at an object, what you actually see is the light, the light bounces off what we look at and penetrates our eye, so the light is converted into an electrical signal that our brain transforms into an image. This process lasts 1/10 th of a second. So at all times, our brain receives a tremendous amount of information and it's hard for him to try to focus on everything at the same time. But your brain does not simply receive this information—it creates your perception of the world. This means that sometimes your brain fills in gaps when there is incomplete information, or creates an image that isn’t even there! Why does this happen? Evolution! Survival depends on fast reactions. Your brain has evolved to work quickly to piece together whatever bits and fragments it can get—and to do its best to figure out the rest. An example is the illusion of Hering (and you make the slide appear).
- When you take two straight lines and put them in front of this radial pattern (you slide down the slide) they look distorted even if they are straight in reality. The explanation is that when our brain sees this radial pattern, it focuses on the point in the middle, and it looks like you are traveling towards it. Our brain then thinks that these parallel lines are getting closer and they seem to be getting closer as we get closer to the center of the radial pattern and that is why the lines look distorted.
- All illusions do not deceive your brain by making it see movements, others can deceive him by showing colors or nuances that are not really there. -1- ILLUSION 1: This pile of ascending gray bars seems to be lighter at the bottom of each bar, but if we separate them we notice that they all have a solid color, it is due to an automatic process of our brain called "lateral inhibition" that helps to find the limits of an object. -2- ILLUSION 2 (Must pass the animation to display the 2nd illusion): This is called the peripheral drift, the snakes that turn, we can not help but see a creeping movement on the image. But when you focus on any point, the movement stops. This is due to how we interpret light and dark and partly to our eye movements. The clear, dark colored sequence of each of these snakes deceives the movement-sensitive neurons, pushing them to respond as if it were a real physical movement.