TUTORIAL
Cross-eyed viewing

illustration

Did you know it is possible to see 3D images without special glasses?

What if I told you that your eyes have a hidden superpower? The ability to see 3D images without special glasses.

We see in 3D because our two eyes perceive two different points of view. To recreate this phenomenon with printed or displayed images, there are various devices: polarized glasses, holograms, lenticular arrays, anaglyphs, stereoscopes and virtual reality headsets.

But there is a trick, which few people know, to fuse the two images of a stereoscopic pair (one image for the left eye and another for the right eye) without any special device.

To do this, a simple eye gymnastics and a little practice are all you need: this is cross-eyed viewing.

The animation below shows what should happen:

  1. The two images are displayed side by side.
  2. Cross your eyes slightly, neither too much nor too little. The two images will naturally double, thus creating four images.
  3. The two central images will then merge into one. This image will then appear perfectly sharp AND in 3D.
Cross-eyed viewing

Put it into practice!

So, ready to test your cross-eyed viewing?
Practice with the two squares below.
In the central 3D image, the white circle will appear deeper than the dark square.

Go ahead! Cross your eyes slightly and let the central image form.

Then you can move on to the “MATIS” stereoscopic pair.

Cross-eyed viewing
Couple-Matis

There is another form of eye gymnastics, known as parallel viewing, which you can use to view autostereograms.