Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: MikeS on 17/03/2012 19:25:06
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A camera lens distorts vertical lines towards the edge of the image such that they appear to be curved.
Why do the lenses in our eyes not produce the same distortion or does our brain automatically compensate and remove the distortion?
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The lenses in our eyes are greatly inferior to those in cameras. What you "see" is the result of some amazing image processing in your brain combined with your eyes' ability to scan like crazy without making you want to puke.
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As you say Mike although the image on the retina is distorted at least as much as that produced by the Camera the brain learns to compensate.
Athough being short sighted since birth I did not begin to wear spectables until I was 25 years old and at once began to get much distorted albeit much better focused vision, after a month my brain built the new software and I now see geometricaly undistorted vision with or without my spectables.
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Your brain does a lot of "processing" to make sense of images. Making straight lines appear curved, or curved lines appear to be straight.
Keep in mind that your eye is a very wide angle lens, so it should demonstrate a lot of distortion. However, I would think the spherical shape of the retina would help reduce the distortion. So, if you built your camera with a spherical photo sensor, you would reduce the distortion somewhat, but then you would still have to do some calculations to project that back onto a flat plane.
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after a month my brain built the new software and I now see geometricaly undistorted vision with or without my spectables.
Good point about the glasses. I started wearing glasses in grade school, for astigmatism. Astigmatism gives one a distorted shape of the eyeball, so a distorted focus. I can still remember the first few days where they threw me completely off kilter.
Now, I can do fine with or without the glasses, only noticing better vision for fine details with the glasses. Walls still appear straight with or without the glasses.
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Keep in mind that your eye is a very wide angle lens, so it should demonstrate a lot of distortion.
It has a wide angle, but except for a small area in the center, it's horribly out of focus. We compensate for that by doing a lot of scanning.
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The scanning cameras on weather satellites have a very small F number and scan the spherical Earth producing a very geometricaly distorted picture, the early Russian satellites did not correct this but all modern ones have image processing correction.
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The focal plane in a camera is flat, but in the eye it's curved - that'll make quite a difference. Similar issues emerge when displaying an image on a curved surface rather than a flat screen - ideally we should be using curved screens right in front of our eyes.
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... we should be using curved screens right in front of our eyes.
https://en.wikipedia.org/wiki/IMAX#IMAX_Dome_.2F_OMNIMAX
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Thanks for the replies guys.
I had wondered about the curved retina and brain processing thing.
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Having blurry peripheral vision is probably an evolutionary advantage. Our peripheral vision is still very good at detecting sudden changes, and it's even a bit more light sensitive than our straight-on view.
If everything in our field of view was in focus, it would take far more processing and, presumably, much larger brains, which be an evolutionary disadvantage.
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Blurrry peripheral vision is probably vital because of the sun - you have to be able to see in directions where the sun is in the scene without your retina being burnt by it.