[Tech1] Eyes

[Graeme Wall]

Simple optics sas we normally see things upside dpwn and the brain learns to correct at a young age.
— 
Graeme Wall


> On 26 Apr 2020, at 00:15, Geoffrey Hawkes via Tech1 <tech1 at tech-ops.co.uk> wrote:
> 
> When the so called “Magic Eye” 3D pictures first appeared back in the eighties(?) there was a large poster in a shop window with a notice saying “Can you see the dinosaur?” I looked and could see nothing other than the mishmash of small coloured shapes and dismissed it as a hoax. Some time later when the craze still hadn’t gone away I bought a book of such images and read the notes on how to view them in 3D. It took me a while but when I got the knack of how to do it, I was amazed at seeing the hidden 3D pictures. For some of them you need to let your eyes focus forward, ie to converge and others you need to focus back as though you were looking through the picture at a distant object, ie to let your eyes diverge. I’m still puzzled as to how the images are produced to make them work.
> Now when I see anything with a repeating pattern on a table cloth or something like that, I amuse myself like Roger with his wallpaper by staring at it dreamily and can sometimes see parts of it apparently floating above the other.
> I tried the same with Bernie’s picture of the beehives but only with partial success as the images were side by side and weren’t meant to be viewed with the naked eye.
> It’s all fascinating stuff and another example of how our brains interpret what we see. Back in the fifties I remember hearing about an experiment where the participants wore goggles which vertically inverted what they saw and how after a while their brains corrected it so they saw things the right way up again. Amazing or what?
> Geoff
> 
> 
> 
> Geoff
>> On 25 Apr 2020, at 20:50, ROGER BUNCE via Tech1 <tech1 at tech-ops.co.uk> wrote:
>> 
>> 
>> When we put up some new wallpaper in our living room, it seemed to do nasty things to our eyes. The problem was that it was a small dot pattern, and the spacing between the dots was roughly the spacing between your eyes. So, your eyes could find themselves looking at different dots, while your brain assumed they were looking at the same dot. This was fine, until you looked away, when you got an unpleasant sensation of your eyes being sucked out of your head! Now that the wall paper is no longer new, and we no longer bother to look at it, the problem has gone away.
>> 
>> The enlargement effect - I think I can see a logic there - triangulation. If your eyes are looking nearly parallel, then your brain might naturally assume that you are looking at something far away. If your eyes are more convergent, then it might assume that you are looking at something close. So, if the image believed to be far away, appears to be the same size as the image assumed to be close, then your brain might explain this to itself by assuming that the far away object is larger. (Does that make any sense? I know what I mean even if I haven't explained it very well!)
>> 
>> luv, Rog.
>> 
>> On Saturday, 25 April 2020, 18:07:07 BST, Mike Giles via Tech1 <tech1 at tech-ops.co.uk> wrote:
>> 
>> 
>> Yes, Dave, I agree that besides the stereoscopic effect, everything did seem to be enlarged. I often use subtitles on the TV after my wife has gone to bed, as there is so much mumbled speech nowadays that it needs to be reasonably loud to catch all the asides, and very often the text appears to be in a different plane from the picture ~ almost as if they are on a separate screen very slightly in front of the TV.
>> 
>> Mike G
>> 
>>> On 25 Apr 2020, at 12:18, patheigham via Tech1 <tech1 at tech-ops.co.uk> wrote:
>>>  
>>> Do you have to be ‘cross-eyed’ to do a cross-fade?
>>>  
>>>  
>>>  
>>> Sent from Mail for Windows 10
>>>  
>>> From: dave.mdv via Tech1
>>> Sent: 25 April 2020 11:37
>>> To: Mike Giles; tech1 at tech-ops.co.uk
>>> Subject: Re: [Tech1] Eyes
>>>  
>>> I also experienced a similar effect looking at the sound desk in my scanner but the images seem to be enlarged, when I brought the eyes back together it all went further away! Looking at my monitor now I can 'split' my eyes and see two images about 2" apart e.g.  'before lunch as well before lunch as well'. Cheers, Dave. PS. It happened before lunch as well!
>>> 
>>>  
>>> 
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