How Stereo Images Work

3D Vision. Human beings have three-dimensional vision. This is because our eyes are on the front of their heads and they are spaced a few inches apart. As a result, each eye views the world from a slightly different angle. Our brain combines the image from each eye and forms a single three-dimensional view of the world.

Artificial 3D Images. To create artificial 3D images, you have to simulate what our eyes see. As a result, you need to create two images, each presenting a slightly different view of an object. Each eye is then shown a different image, thus simulating what you see when you look at the real world.

This is the way the “View Master” toy works. To make the View Master reels, they would take two spaced photographs of a scenes, from slightly different angles. When you look through the viewer, the eyes see these two image and they appear to be 3D.

These techniques are widely used in science and engineering. For example, cartographers use this technique with aerial photographs. By taking spaced photographs of the ground as you fly across the land, you create photographs that view the ground from different angles. If you view two of the photographs together, the mountains and valleys appear three-dimensional.