My Coffee News ad appearing on 2 February 2012 features a 3-dimensional image of the Cucamonga Type logo. This article is intended to help those who may have difficulty visualizing 3-D images.
How 3-D Vision Works
The first illustration shows a view of the Chicago skyline as seen from the middle of Lake Michigan. This image cannot be viewed in three dimensions. This is because both the left eye and the right eye see identical views of this panorama.
What allows one to see three dimensionally is that, since humans have two eyes, each eye sees a unique view of the surrounding world. See the second figure.
In this illustration, both the left eye and the right eye focus on the top of the sailboat mast. However, when this is done, the left eye sees the tip of the mast against the Leo Burnett building (green arrowhead), whereas the right eye sees the top of the mast in front of the right edge of the Daley Center (red arrowhead), just to the right of the Mid-Continental Plaza. (The Buckingham Fountain is obscured by the yellow-orange clump of trees in the very center of the illustration.) Because the boat in the foreground appears to “move” a significant amount against the cityscape background, our brain interprets the boat to be closer to our eyes than the rest of the city and, hence, we see it as being nearer to us, thus defining the third dimension.
Visualizing the Third Dimension
There are two methods for creating 3-D images from a flat photograph. Both require at least two separate images, although many stereograms (or stereoscopic photos and illustrations) incorporate both images into a single photo or illustration. In one method, the viewer must view the stereo images cross-eyed. In the examples shown here, a parallel-eyed method is used. Essentially, the viewer needs to view the two images as if focussing on an object across the room, so that the two eyes are both pointed generally straight ahead. When viewed in this way, the left eye focusses only on the left image and the right eye focusses only on the right image.
One way that this can be accomplished is to look at the stereo images with the eyes relaxed and non-focussed. Initially, the two images will overlap each other in the field of view in a haphazard way. At that point, begin to coax the eyes to focus on the outlines of the images and bring them together to merge into a single rectangle. Notice the two black dots at the top of the illustration. When you are properly focussing on the images, these two dots will merge together until only a single dot is seen in the center of the field of view. You will then see something that looks like the following.
The center image can be seen to be three-dimensional. The boat will seem to float on the water in the foreground of the illustration and the cityscape will float over the blue sky background. Various other elements of the image will also appear to be at different depths in the photo. In fact, this illustration contains elements at ten different depths in the field of view (some are very subtile).
When learning how to view 3-D images, I found it helpful to take a sheet of paper and place one edge at the tip on my nose and position the opposite edge between the two stereo images. This helped me to force the left eye to see only the left image and the right eye to focus only of the right image.
A second way to find the stereo image is to focus on some distant object, such as a door knob located across the room from you. Once you are focussing on the distant object, slowly move the stereogram until it is directly between your eyes and the distant object and allow the eyes to focus on the stereo images as described above.
I hope you enjoy viewing this ad as much as I enjoyed creating it!