The first time I came to know about stereograms was in 1997, when a friend stumbled upon one with Einstein's image in it. I couldn't see Einstein among all those patterns of pixels of various colors. I didn't know also how to discover the image among those pixels.
But, I remembered the name of the picture: stereogram. Later, over the years, time and again, I tried to view images hidden in stereograms, with little success.
Sometime around 2008, almost 11 years after I was shown the first stereogram, I could see few pictures, thanks to the Wikipedia page on it. I could see the 3-D image of the Asiatic hybrid Lilium and some images with pictures in multiple planes in the wiki page on autostereogram. I got some help on viewing these from the web pages of eyetricks. My favorite among the 3-D stereograms is this image of statue of liberty. These images are somewhat easier to view, simply because these are images rather than patterns of pixels as we can see in most of the stereograms. BTW, these stereograms which shows a high number of pixels of different colors are called "random dot autostereograms".
I got stuck at unearthing the shark at this image, this wiki page shows another pic below the stereogram that shows the shark in white with black background. Since I could see the 3-D images by this time, I was expecting to see another plane behind the random dots where the shark lies. This wrong anticipation was the main reason, I guess, of my inability to spot the shark for a long time. Once, I cracked it, I was able to see similar hidden pictures behind other similar random dot autostereograms.
So, how to visualize this shark? Imagine that there is some dough, and somewhere in the middle of it you have made a pothole-like depression that has got the shape of the body of a shark, as if the shark is just lying at the surface of the dough - half of its body is above the dough. Now imagine the dough having the random dots on all over the surface of it - so, naturally, these dots are also on the visible surface of the depression on the dough. This is exactly what you can see from this picture if you focus in the right way.
Coming back to the stereogram of Einstein, which can be seen here. Now, I can see Einstein here: its just outline of his face, nobody could identify him without the hint in the background of the image. I would keep the shark image that appears on the stereogram page in Wikipedia as a better example of a random dot autostereogram.
But, I remembered the name of the picture: stereogram. Later, over the years, time and again, I tried to view images hidden in stereograms, with little success.
Sometime around 2008, almost 11 years after I was shown the first stereogram, I could see few pictures, thanks to the Wikipedia page on it. I could see the 3-D image of the Asiatic hybrid Lilium and some images with pictures in multiple planes in the wiki page on autostereogram. I got some help on viewing these from the web pages of eyetricks. My favorite among the 3-D stereograms is this image of statue of liberty. These images are somewhat easier to view, simply because these are images rather than patterns of pixels as we can see in most of the stereograms. BTW, these stereograms which shows a high number of pixels of different colors are called "random dot autostereograms".
I got stuck at unearthing the shark at this image, this wiki page shows another pic below the stereogram that shows the shark in white with black background. Since I could see the 3-D images by this time, I was expecting to see another plane behind the random dots where the shark lies. This wrong anticipation was the main reason, I guess, of my inability to spot the shark for a long time. Once, I cracked it, I was able to see similar hidden pictures behind other similar random dot autostereograms.
So, how to visualize this shark? Imagine that there is some dough, and somewhere in the middle of it you have made a pothole-like depression that has got the shape of the body of a shark, as if the shark is just lying at the surface of the dough - half of its body is above the dough. Now imagine the dough having the random dots on all over the surface of it - so, naturally, these dots are also on the visible surface of the depression on the dough. This is exactly what you can see from this picture if you focus in the right way.
Coming back to the stereogram of Einstein, which can be seen here. Now, I can see Einstein here: its just outline of his face, nobody could identify him without the hint in the background of the image. I would keep the shark image that appears on the stereogram page in Wikipedia as a better example of a random dot autostereogram.
