Seeing the unseen beyond an image

By Lim Tri Santosa

BANDUNG (JP): In the information age, the eyes are really taking a beating. Our society has become so visual, we practically use our eyes for everything we do. Does this mean that our eyes are already getting plenty of abuses? Well, if we were to take a survey of Internet users asking how it felt after seven hours at the computer, I'm guessing that most Internet users would agree that their eyes were being overused and abused rather than exercised in some healthful way.

It seems clear that we may need to start taking better care of our eyes as well as our bodies. Such as? For one thing, we can try to remember to take plenty of breaks from computer gazing and other near-point work. Take eye breaks by looking off into the distance and focusing on many different targets. You can also take eye breaks by 3 dimensional (3D) viewing stereo images.

Today, 3D virtual reality systems require bulky accessories, such as headsets and gloves. Forget the fancy gear, you don't need those crutches.

At the following websites, you can learn to see 3D view with nothing more than your own eyes and brain. Find out what your own biological unit is capable of doing, we really do have our sixth sense.

Stereographic 3D vision allows us to perceive the world as 3D objects look like they are in front of other objects. What allows us to see in 3D is the fact that our eyes each see a slightly different image. A simple test to see if you will be able to see the images in the stereograms is doing "The Famous Frankfurter Experiment" (www.vision3d.com/fftext.html). Hold your index fingers up in front of you and look at something behind it. Without shifting focus to your fingers, how many fingers do you see? If you see two ghostly images of your fingers floating in the air, this is the first step toward being able to see our 3D images.

Each eye captures its own view and the two separate images are sent to the brain for processing. When the two images arrive simultaneously at the back of the brain, they are united into one picture. The mind combines the two images by matching up the similarities and adding in the small differences. The small differences between the two images add up to a big difference in the final picture. The combined image is more than the sum of its parts. It is a three-dimensional stereo picture.

With 3D stereo vision, we can see where objects are in relation to our own bodies with much greater precision, especially when those objects are moving toward or away from us in the depth dimension. We can see a little bit around solid objects without moving our heads and we can even perceive and measure empty space with our eyes and brains.

There are some examples of general actions that depend heavily on stereo vision such as throwing, catching or hitting a ball, driving or parking a car, threading a needle and sewing, reaching out to shake someone's hand or pouring liquid into a container. I still remember about ten years ago when I was learning to park my brother's car in the garage and made a big scratch on its left doors, I guess I didn't have stereo vision that time. Occupations like football player, driver, architect, surgeon or dentist really depend heavily on stereo vision.

Stare at the stereogram 3D picture. Don't focus on the patterns on the surface.

Instead, try to focus beyond the picture. It may take a few minutes but you should see a 3D image emerge from the random patterns. Our two eyes view normal scenes from two slightly different angles, so objects at a distance appear shifted slightly to the left or right. The amount of shift depends on the object's distance. This shift is called parallax. The difference in the left-right placement is perceived by our brains as a difference in depth.

Some people see the 3D pictures very quickly, others may need to spend awhile practicing before seeing their first stereogram. Still others never see the image. If you are having difficulties, remember to be patient. If you know of someone who can see the images, ask for advice. There are a lot of different tricks people use to see the images.

Seeing a 3D object for the first time can be surprising as you do not expect to see something standing out from a page. Good luck!

To start your journey into the 3D world, hit your browser at http://www.magiceye.com/3dfun/stwkdisp.shtml, http://stereogram.i-us.com/, http://www.softsource.com/stereo.html, http://www.ccc.nottingham.ac.uk/~etzpc/sirds.html