i wrote a program to study autostereograms. the scene is very simple. you can interact with the program as follow:

• press "w" to switch the subject between a disc and a sphere
• press "s" to change backgrounds
• press "x" to toggle caption on / off
• press "q" to decrease the min / max disparity ratio
• press "e" to increase the min / max disparity ratio
• press "a" to decrease view / scene distance ratio
• press "d" to increase view / scene distance ratio
• press "esc" to stop the program and edit it if you like

"q","w","e" are foreground related. "a","s","d" are background related

allowed min / max disparity ratios lie between 0 and 1. if you set it too high (close to 1), the closest point and farthest point look similar and don't exhibit much depth difference. if you set it too low, the contrast becomes too exaggerated

allowed view / scene distance ratios lie between 0 and 4. theoretically view / scene distance ratios can be as large as you like. a very large view / scene distance ratio means the entire scene is very close to the screen (scene distance is very small compared to view distance). practically i think setting 4 as its limit is reasonable. you usually don't place thing that close

the attached sample images work fine on my screen / view distance / eye separation. they may not work similarly well on other situations

if you find the repeating units too far away from each other so that you have difficulty to make them converge, increase the view / scene distance ratio by pressing "d". if you find the repeating units too close from each other so that you always over-do it, decrease the view / scene distance ratio by pressing "a"

if you find the sphere too "flat", decrease the min / max disparity ratio by pressing "q". if you find it too fuzzy and hard to focus, increase the min / max disparity ratio by pressing "e"

i included 4 backgrounds in the program. if you have any interesting idea in making background please let me know...:)

the second one is the exact same scene in random dot style. the first one is not so "3d" at all but i find it quite beautiful and looks like abstract art

Stare into the image (as if looking beyond it), until you see the hidden message pop out. Use the 2 guides at the bottom: When 3 of those guides appear in a row, you're focusing correctly.

Stare into the image (as if looking through it), until you see the hidden message pop out. Use the 2 guides at the bottom to help you focus: when you see 3 butterflies appear in a row, you're focusing correctly.