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Post by HeadLikeARock (was postbaguk) on Jun 1, 2007 7:01:59 GMT -4
The Gimp reports that A and B are both approximately 47% gray, within a fraction of a percent. This is actually an example of a well-known exercise in contextual perception, one that appears all the time in photographic interpretation textbooks. I imported the image into Corel Photopaint and sampled each area with the eye dropper. Dave's right. Each square showed an RGB value of 120,120,120. My eyes told me they couldn't be the same, but they are. Good one Dave. That's the way I had to prove it to myself as well. I didn't even trust my eyes when using the dropper tool in MS Paint and painting a thick line right through the middle of both squares... I had to check the actual values in Photoshop. Even THEN I was looking for ways it might be some kind of con. Even though I now KNOW they are both the same colour, I still cannot get them to "appear" the same in my head... no matter how hard I try (unlike some illusions where once you know what the trick is you can "force" your brain around it). Sad thing is, I used this once in a discussion with someone on another moon hoax forum as an illustration that common sense is not always a reliable tool when examining photos, and was promptly accused of playing twisted mind games. And this from a self-styled "open-minded truth-seeker". The irony in that last statement is so painful it makes me wince.
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Post by svector on Jun 1, 2007 7:21:00 GMT -4
Sad thing is, I used this once in a discussion with someone on another moon hoax forum as an illustration that common sense is not always a reliable tool when examining photos, and was promptly accused of playing twisted mind games. Mind games? Gosh, I wonder who that might've been.
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Post by Kiwi on Jun 1, 2007 8:03:29 GMT -4
I believe it now, but my eyes are still holding out. No, it's your brain that's holding out. Your eyes are fine. I feel that the perceptual or "common sense" problem we all experience with this illusion comes from our brain -- perhaps our subconscious -- telling us how things should be, based on long experience, and I sometimes wonder if a young child could more easily see that A and B are the same shade of gray. Even after decades in photography and spending years analysing photographs for customers in my camera store and when judging photographic competitions, this illusion still fools me, even though I know from testing it with a nifty little colour-picker program (HTMLcolor v1.4) that those squares are both 120-120-120 gray. When I look at the whole picture, I only know that square B is darker than the fully-lit light-gray squares, but I cannot intellectually accept that it is as dark as square A. It's just not right, even though the facts tell me otherwise. It's the same with the width of the path from my house to the front gate. It is parallel-sided and about 35-40 meters long. I have looked along it for years from my lounge window and cannot intellectually accept that visually the near end is much more than twice as wide as the far end. Yet when I measure it by simply holding up a finger or using a ruler, the near end is visually about five times wider than the far end. Again, I think that my subconscious knows that the sides of the path are parallel, so convinces my conscious thinking that the effects of perspective are nowhere near as extreme as they really are. Our brain reinterprets what we see to fit in with what it understands about our visual world, and in doing so it sometimes fools us. Try looking along any similar set of parallel lines and see if you have the same trouble mentally working out the relative visual widths of the near and far ends.
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Post by Joe Durnavich on Jun 1, 2007 8:05:15 GMT -4
Even though I now KNOW they are both the same colour, I still cannot get them to "appear" the same in my head...I think if you get the image small enough so that the squares are smaller than your visual system's receptive fields, you will have a better chance of seeing them as the same shade. This page has a smaller rendition of the illusion: www.moillusions.com/2006/03/impossible-triangle-illusion-no2.htmlIf I step back a little and try to position by eyes so that I can see squares A and B at the same time (instead of having to scan from one to the other), then square B looks as dark as square A. Sort of. I sometimes get the impression that square B is both light and dark at the same time, as if it were in a superposition of both states. And then I get the feeling that somebody's cat will die, or half die, if I continue.
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Post by Joe Durnavich on Jun 1, 2007 11:06:36 GMT -4
Your eyes are fine.
Yes, the eyes are fine, but I believe they are playing a role here. There are neurons in back of the retina that react to contrast in an area based on the surrounding light intensity. This gives rise to several illusions. I am not sure if this illusion in particular falls in this category, but it does seem to be such a contrast-based illusion.
And before you all go to trade in your brains for better models, consider that if we were looking at a photograph of a checkerboard with a shadow casted across its surface and were asked the color of square B, we would give the correct answer: square B is a white square.
The optical information that square B is white is in the scene. We can and do pick up that information. It is just not "common sense" the role illumination has in color judgment, or perspective has in shadow angles, etc.
I feel that the perceptual or "common sense" problem we all experience with this illusion comes from our brain -- perhaps our subconscious -- telling us how things should be, based on long experience,
You had to learn how to judge the colors of objects. When your teachers showed you white objects, you would have seen them under a variety of illumination contexts. With practice, you developed the ability to identify white squares even when they were in shadow.
and I sometimes wonder if a young child could more easily see that A and B are the same shade of gray.
I suspect not--if only because when the child is old enough to answer the question, it is probably too late. Notice that when children draw, they don't draw in perspective. They draw wheels on a car as circles, for example, even though from most perspectives they are oval. The ability to draw in perspective comes only later in life, after you learn to notice the perspective aspects of what you see.
A skilled artist will still see squares A and B as different, but if asked to paint the illusion, may very well pick the same paint for both squares. We can see that square B is a white square in shadow. The square does look dark, in that sense, even though it also looks light.
I have looked along it for years from my lounge window and cannot intellectually accept that visually the near end is much more than twice as wide as the far end.
Parallel shadows or other features, which converge in a photograph, tend to still look parallel to me in the photograph. I have to hold up my hands to see them as the artist does.
Again, I think that my subconscious knows that the sides of the path are parallel, so convinces my conscious thinking that the effects of perspective are nowhere near as extreme as they really are. Our brain reinterprets what we see to fit in with what it understands about our visual world, and in doing so it sometimes fools us.
Consider it this way: You had to learn what parallel lines are. You learned that by observing parallel lines from a variety of viewing angles, even learning how the lines change as you move around. Your pathway presents the same optical stimulus as you move, so you recognize it as actually parallel. In that sense, you really do see something that is in the environment.
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Post by nomuse on Jun 1, 2007 14:03:00 GMT -4
Actually, after a number of years as a scenic carpenter, often eyeballing wooden frames to see if they were straight, parallel, at right angles et al I began to wonder if the ability to see these pure forms not generally present in nature is more like the zero of a complex visual system meant for navigating trees. Basically, the system adapted to a "if these branches were straight, they'd look like this"; and never really expected to encounter the simple form of the problem, aka an actual straight branch (or the side of a building).
On the other hand, I know our visual system gets very upset with large buildings, large expanses of square wall, and so. But then, I don't think it ever had a pressing need to see those that clearly. Office buildings rarely leap at you out of the tall grass.
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Post by PhantomWolf on Jun 4, 2007 17:58:23 GMT -4
Heh, I copied it into PaintShopPro, cloned a square and dropped it between the 2 so it connected them, the bottom square appears to "darken" till they are the same colour. Take the middle square away, and 'B' lightens again, it's a weird feeling watching it.
Now back to the last topic.
Rocky. You were asked what could have prevented NASA from sending someone to the moon, your claim was that they could have gotten through the VA Belts without 6-feet of lead shielding. Now while that is wrong (we know that the Soviets weren't planning to use six feet of lead shielding on thie ships and that the new missions from the US and the planned missions from the Chinese and Russians aren't going to be using 6 feet of lead shielding on their ships) even if it was right, what stopped them from simply building a space ship with 6 feet of lead. Okay yes it would have required a bigger rocket, but then they had the designs for a bigger rocket, the Nova. This rocket was huge, it would have dwarfed the Saturn V and up until it was decided that there wasn't a lot of point in sending a huge ship to the moon, but rather a better idea was just splitting it up into modules, the Nova was the primary launch vehicle for the missions.
Now assuming that NASA had the money and the advanced technology required to pull off a near flawless hoax, what stopped them just using that money and technology to build a bigger rocket and a better shielded spacecraft?
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Post by tofu on Jun 12, 2007 9:56:31 GMT -4
Can anyone explain this? www.youtube.com/watch?v=k3BjSW59tmc7 minute 5 second mark There are two different pictures of an astronaut in the shadow side of the lander. One is illuminated and the other is in the dark. Has anyone noticed the awesome comments attached to that video? There is a hoax believer there demanding a list of every scientist who believes apollo!
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Post by JayUtah on Jun 12, 2007 10:03:20 GMT -4
It would be hilarious to ask him for the name of just one who verifiably doesn't and see if he could produce it.
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Post by scooter on Jun 12, 2007 11:38:22 GMT -4
He'd probably come up with Kaysing...head rocket engineer, program director, vice president for propulsion systems...the man's resume has gotten "larger than life" in some places.
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Post by JayUtah on Jun 12, 2007 12:09:14 GMT -4
[Kaysing's] resume has gotten "larger than life" in some places.
Quite true. But it's interesting to note that I've never found where Kaysing himself misrepresented his authority or expertise. A number of people have promoted him in absentia, but Kaysing seemed to remain consistent to a set of credentials he could (and did) document. It's not a sufficient set to substantiate his claims, of course, but it's consistent.
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Post by nomuse on Jun 12, 2007 16:44:31 GMT -4
Back to optical illusions for a moment....here's a cheap laugh: www.galactanet.com/comic/603.htmI pride myself on being able to see through the meta-illusion. But I definitely had to use a rule to make sure!
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Post by scooter on Jun 12, 2007 16:53:48 GMT -4
It's funny, the human eye can detect parallel and perpendicular to a minute degree, but toss in some distracting context, and "whammo", out to lunch! Those are great, nomuse!
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Post by nomuse on Jun 12, 2007 16:59:23 GMT -4
Heh. I think you missed the meta-illusion. Try that ruler!
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Post by Joe Durnavich on Jun 12, 2007 17:29:15 GMT -4
You're a scoundrel!
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