|Вторник, 21.02.2017, 04:55
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See 3D with a stereoscope
We just got a new camera here at Science by Email so we want to play with it and what better way than creating out own three dimensional photo viewer (a stereoscope) – phoaw! A few of the steps are hard to put in words (but easy to do!), so we'd suggest looking at the big pictures as well as the written instructions.
You will need
WARNING: Take care using the craft knife; younger readers should ask an adult to help or do this step.
What to do
Even though most of us get to see in three dimensions all the time, the novelty doesn't seem to wear off, and it is still a treat to see pictures that are two dimensional jump out at us through the stereoscope.
It is all about how your eyes see things. Our two eyes see the world from slightly different angles and this gives us depth perception. Place a hand over one eye, and then place it over the other eye - can you see the difference? And while you are at it, notice how it has become difficult to judge distances when you are one-eyed.
Our eyes are about six centimetres apart, and the two images they each see are sent to your brain where they are combined into one three dimensional picture. Each eye sees the world at a different angle and your brain does some clever trigonometry to judge distance.
You took a photo of your subject from slightly different angles, just like your two eyes. You then put these pictures back together by manipulating their reflections with the mirrors, creating a three dimensional image, without your brain having to do any work at all! Two images that form a 3D image are called a stereo pair.
Aerial photography that allows you to see the landscape as a three dimensional image is extremely valuable. If a plane takes two images at different angles, a stereoscope can then allow you to see the world from above in three dimensions. This is great for land management as it lets you see a photo of hills and valleys and contours. And if you were studying a forest, it's useful to have three dimensional images of the forest canopy to examine its structure from above.
They also make a great toy and have done ever since their invention in the mid 1800s.
Here is the centrepice mirror for your Stereoscope.
How to set up your stereoscope.
Here is how you use your stereoscope.
You will feel a lot like Alice in Wonderland.