3D Photos

Anaglyphs are images that simulate three dimensional images by supplying slightly different images to your right and left eyes. The most common way to make anaglyphs is to take two black-and-white photos from a few inches apart (as your eyes are), color one (by convention, the left one) red and the other blue, then merge them together. To view them you need the “3D glasses” with a red filter over your left eye and a blue filter over your right eye.

The image at right is an anaglyph that I made this morning, using a handheld digital camera and Photoshop. The image is of a chaparral-covered hillside adjacent to my home. I had to do some “fixing” with Photoshop, as I had aimed the camera slightly differently between the two photos, plus I rotated the camera slightly. But once I fixed that stuff, coloring and merging them was easy — and the results, to my surprise, quite effective. If you click on the photo at right to get the full sized copy, and use the 3D glasses, you’ll be able to easily see how the various shrubs are at different distances. To my eye, these distances seem quantized, as if there were some fixed number of “layers” to the resulting 3D image. I speculate that this is a side-effect of pixelization — the image isn’t “analog” like what your eyes actually see, but is composed of discrete pixels — so the offsets between the images for your left and right eye are limited to integral pixels. Of course in the real world our eyes are doing the same thing, but … there are many more “pixels", and the pixels are not on a regular grid, which I believe would mitigate the quantization to a large degree.

There’s another surprise for me in making this anaglyph: the resulting image, viewed without 3D glasses, looks quite blurred. But with the 3D glasses, all the crisp detail comes back! This I didn’t expect at all…