Naked Science Forum
Life Sciences => Physiology & Medicine => Topic started by: alancalverd on 26/12/2023 10:44:35
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You are probably familiar with the "skeleton cube" illusion, where the 2-D lines look like a transparent cube that "flips in and out" as the brain tries to interpret it as a 3D projection.
I recently noticed something similar and different. Look at this static image - the title frame of a video posted by Hamdani:
https://www.thenakedscientists.com/forum/index.php?topic=77747.msg718103#msg718103 (https://www.thenakedscientists.com/forum/index.php?topic=77747.msg718103#msg718103)
The title runs across the center and is overlaid with the icon for the "start button".
When I gaze at it, the words "fade" and the icon gets brighter, then the opposite happens. It's almost as though my eyes defocus one or other piece of information, though they are both the same color, in the same plane, and contain no perspective clues at all!
I've tried printing the frame but the effect isn't as strong on regular inkjet paper. It seems that you need a really bright, high contrast image (I'm using a seriously good monitor under optimal viewing conditions here) but it might work with photo paper. It certainly works if you can snip and magnify the image to full screen. NB - don't just click on the "full screen" icon - it skips to a different presentation! You need the monochrome image only.
It's vaguely reminiscent of "ring artefacts" in medical CT test images of a homogeneous phantom: they are "obvious" to the human eye, but when analysed pixel by pixel there is no radial correlation at all - purely random noise.
Any idea what's going on?
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Hi.
I don't know but it sounds like stuff that is explained by the usual conventional psychology and physiology.
Staring at any image for too long can lead to distortion and especially fading. This is mainly due to photosensitive pigments in the retina being depleted when you keep your eyelids open and pupils fixed open wide. The effect was a big problem for early Astronomers who found that staring intently at the very dim stars did not help at all: They just faded away to nothing, the only chance you had to see them was when you took quick glimpses at the sky, you must scan across the sky and frequently close your eye lids to stand any chance of seeing these dim stars. This problem (for Astronomers) is easily resolved by using a camera instead of your own eyes, where you do get what you want when you keep looking at a dim object for more time. Obviously a camera film becomes more developed and hence dim stars are more readily detecetd the longer you leave the camera set up with the shutter open.
More generally, you must move your gaze to see everything. Bright areas would otherwise rapidly deplete your photo-sensitive pigments and then your brain or psychology will also step in and try to make sense out of the image. In your case, the writing is not normal: You wouldn't expect to see writing suspended in the air in a real scene but the human figure is much more important and human evolution has made you highly attuned to identifying human figures. Your brain will fill in the details so as to try and keep that figure present even if the pigments in that region of your retina were becoming depleted.
Other than this, it could be something to do with age but it's Christmas so I'm not going to talk about that.
Best Wishes.
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I think ES is hinting that old fogeys like myself and Alan are suffering from the effects of advanced ageing. A dreadful concept!! (only joking).
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@Doc
I can't see what you see.
: (
Wish i could!
But Good Observation thou.
Only after Staring at it for a loonnng time did i realize that the ' TexT ' is not in the Background, rather at the Forefront of the ' Image ' .
& that ' Play ' button seems to be Superimposing upon the Text line, it looks like it's embedded or immersed within the Text but it's not, rather it's a layer atop.
ps - Age is just a num63r, Maturity is a Ch01ce!
(Styles)