Evo dva objašnjenja:
"Out brains use shadows as clues to decide whether something is raised up or pushed in. Humans are used to light always coming from above; from the sun, room lights, and so on. We are so used to light coming from above, that when we turn a picture over the brain is fooled by shadows in the "wrong" places, and sees "in" as "out" and "out" as "in".
Photo interpreters, like scientists looking at moon photos or photos of Mars from orbit often turn the images so the light appears to be coming from the upper edge. It makes it lots easier to tell "up and out" from "in and down".
Most air photos in magazines and textbooks have north at the top of the page just like a map. But the sun comes from the south in the northern hemisphere and that makes it look as if the light is coming from the bottom of the picture! Sometimes it is easier to look at these pictures if you turn them upside down.
One last bit. Being used to having light come from overhead is why someone shinning a flashlight up into their face at Halloween looks so freaky! We know it is a face, but the shadows are all wrong!"
Bob Avakian
Oklahoma State University - Okmulgee
"We are accustomed to seeing scenes lit from above, because the sun is usually overhead and never below us. Satellite photos of terrain, however, only show shadows when the light source is nearly horizontal with the surface.
When a crater is illuminated from above, the shadow inside the crater is near the top and the bright part is near the bottom. A mountain shows exactly the opposite lighting pattern: bright at the top and shadowed at the bottom. This is because the part of the crater or mountain that is most perpendicular to the incoming light reflects it the best. Anyway, your brain interprets pictures under the assumption that the light is from the top of the scene. So if a picture shows an object that is bright at the top and dark at the bottom, it interprets it as a mound lit from above, not as a crater lit from below."
Richard Barrans
Department of Physics and Astronomy
Anketa
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