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-   -   This is odd (http://www.zefrank.com/bulletin_new/showthread.php?t=7896)

Max Headroom 03-20-2005 05:07 AM

This is odd
Check out this photo in this this link, but more importanly read the caption below. Interesting questions and observations in the second paragraph.

Go here for a closeup view of this digital oddity.

Any one have any thoughts on this? I say it's the CIA

Malmal11787 03-20-2005 05:16 AM

dunno what to think. my head hurts from looking at it for so long. it draws me in!

shmitty 03-20-2005 06:26 AM

I did the test my self because I'm skeptical. I created a large black background and created large white crossed bars on top of the pattern. Right away I saw the little circles (more of squares because of the size I made it). I used the eyedrop tool to select the section that looks darker and it was the same as the white around it. I don't think the algorithm "falls" for the optical illusion. I don't see how it could anyway because it looks at small sections at a time and compresses it that way. In order to fall for an illusion like this you have to see a significant amount of the picture at the same time. Correct me if I'm wrong please. :D

melissa 03-20-2005 09:35 AM

It's weird, but I don't think it's the CIA.

Max Headroom 03-20-2005 10:38 AM


Originally Posted by melissa
It's weird, but I don't think it's the CIA.

That's EXACTLY how the CIA does it. That or the three men in black suits who run the world.

They run everything I tell ya, EVERYTHING!!!!

Frieda 03-20-2005 10:46 AM

shhhh! dont let em know you know! :eek:

Simage 03-20-2005 08:03 PM

just posted this on flickr too, but it is an artifact of the jpeg compression scheme. I'll see how much of this I remember form class now.

this can be reduced to a black and white image for simplicities sake, then every pixel is a value representing the intensity of a pixel. now if you take a loook at just one row of pixels and look at it as a graph on intensity with respect to time(actually column in this case) we can see that its actually a fairly simple step waveform, now any waveform can be created by the addition and subtraction of other smaller waveforms(wavelets I think they call them) , based on that, if we had an infinite number of cosine waves, we could perfectly represent the original wave we had, unfortunately, storing that much information is .... impractical :) (ie. you'd need an infinately large hard drive to store any image) so some smart people got together (the jpeg group- Joint Photographic Experts Group) and said "hey, the human eye isn't perfect, so if we can retain enough of the signal to fool the human eye thats good enough" and thats what they went on to do, so because of that we don't QUITE match the original waveform and we get som artifacts, in a black and white image like this one you can see them, if you zoom in close enough of color images on a white background you can sometimes see it around the edges.

dunno how much sense any of that made, and I'm reaching back into the dim recesses of me memory of my image processing class, so there may be more than one error in there. :cool:

zenbabe 03-20-2005 08:22 PM

^^^^ ditto!

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