Editing Autostereogram (section)

===Depth maps===
{| border="0" align="right"
| colspan="5" | [[Image:Stereogram Tut Horizontal.png|thumb|350px|Depth map example autostereogram: Patterns in this autostereogram appear at different depth across each row.]]
|-----
| align="center" | [[Image:Stereogram Tut Horizontal Depthmap.png|thumb|center|200px|Depth map greyscale example autostereogram: The black, gray and white colors in the background represent a depth map showing changes in depth across row.]]
| align="center" | [[Image:Stereogram Tut Horizontal Pattern.png|thumb|left|50px|Pattern image]]
|}
Autostereograms where patterns in a particular row are repeated horizontally with the same spacing can be read either cross-eyed or wall-eyed. In such autostereograms, both types of reading will produce similar depth interpretation, with the exception that the cross-eyed reading reverses the depth (images that once popped out are now pushed in).

However, icons in a row do not need to be arranged at identical intervals. An autostereogram with varying intervals between icons across a row presents these icons at different depth planes to the viewer.  The depth for each icon is computed from the distance between it and its neighbor at the left. These types of autostereograms are designed to be read in only one way, either cross-eyed or wall-eyed. All autostereograms in this article are encoded for wall-eyed viewing, unless specifically marked otherwise. An autostereogram encoded for wall-eyed viewing will produce inverse patterns when viewed cross-eyed, and vice versa.{{efn|name=Vice versa}}

The wall-eyed depth map example autostereogram to the right encodes 3 planes across the ''x''-axis. The background plane is on the left side of the picture. The highest plane is shown on the right side of the picture. There is a narrow middle plane in the middle of the ''x''-axis. Starting with a background plane where icons are spaced at 140 pixels, one can raise a particular icon by shifting it a certain number of pixels to the left. For instance, the middle plane is created by shifting an icon 10 pixels to the left, effectively creating a spacing consisting of 130 pixels. The brain does not rely on intelligible icons which represent objects or concepts. In this autostereogram, patterns become smaller and smaller down the ''y''-axis, until they look like random dots. The brain is still able to match these random dot patterns.

The distance relationship between any pixel and its counterpart in the equivalent pattern to the left can be expressed in a ''depth map''. A depth map is simply a [[grayscale]] image which represents the distance between a pixel and its left counterpart using a grayscale value between black and white.<ref name="tyler_cadence"/> By convention, the closer the distance is, the brighter the color becomes.

Using this convention, a grayscale [[depth map]] for the example autostereogram can be created with black, gray and white representing shifts of 0 pixels, 10 pixels and 20 pixels, respectively as shown in the greyscale example autostereogram. A depth map is the key to creation of random-dot autostereograms.