Introduction: How to Make 3D Images of Clouds
How to make 3D images of clouds:
Car with driver, train ticket or airplane ticket (train and airplane need clean windows!)
Image processing software or stereo viewer to create 3D pic.
Or: 2 people
2 cameras (similar is best)
2 walkie talkies or cellphones
Costs: 0.- (or the price of a ticket)
Step 1: Stereo and 3D
We see depth because our eyes are placed apart about 7.5 cm (3 inches). Our brains process the differences between the two images as depth. This works best at distances from 30 cm to 6 m (1-20 ft). So an optimal distance to see 3D would be 1.50 m (5ft).
This means the ratio of the distance between the point where the image is taken and the distance of the object viewed is 1:20, but it can vary between, lets say, 1:4 to 1:100.
When making stereo photos, the ratio 1:20 would be a nice guideline to estimate the distance between the cameras (or between the point where pics are taken).
Step 2: Hyperstereo
Hyperstereo is a way to show 3D in a landscape, where distances are too large to see any depth when the distance between the left and right pic is similar to the one between our eyes: above the ratio 1: 100 there is no depth visible.
The distance between left and right has to be increased in order to get to the 1:20 ratio
If you want to make a hyperstereo of a mountain across a valley, 3km away, you have to get up the mountain across the valley, find a cleared area and make pictures while walking about 3000 /20 = 150 m horizontally. (but 50 or 400 m would still work).
Viewing an hyperstereo does give the impression of everything being in miniature: our brain thinks things are nearby (=small) when depth is perceived.
Step 3: Moving Objects
If you want to make a 3D pic of a moving object, the 2 images have to be made at (almost) the same moment.
So, for hyperstereo you would need a sophisticated radio controlled remote control to operate 2 cameras.
For slower moving objects, like clouds, you could do it with 2 operators, with help of a cellphone or walkie talkie for coordination. This would also work for 3D lightning, since the shutters are open half a minute or so.
Step 4: Go It Alone
However, there is a workaround!
Clouds change slowly. This means there is a time window of many seconds. If you can travel sufficient distance in this time window, you can do it with only one camera, alone.
If you are in a car, or train, you can sometimes perceive the vehicle moving under the clouds, easiest with low clouds which have a clear structure. This is ideal: just snap a series of pictures, like every 10 sec. or so of the same piece of sky. Sometimes a tree or sign will block the view, but there will be enough with a nice clear view.
To estimate the proper distance: the base of clouds is at 1-6 km. If you concentrate on a cloud 30 degrees above the horizon, the distance is 2-12 km. The ideal distance traveled would be 100-600 m.
A car on a highway or a train takes about 6 to 40 seconds to travel this distance!
In an airplane it should be possible to make hyperstereos of bigger weather systems, like large thunderstorms.
The illustration shows a series of 4 pictures taken from a train.
Now the only job is photoshopping to make anaglyphs, unless you can see 3D by the cross eye method.