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Thread: Perception of a crater

  1. #1
    Join Date
    May 2014
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    4

    Perception of a crater

    Why do some craters seem to come off the screen while others sink into the screen? This is making it quite difficult to distinguish boulders from craters. Any help would be greatly appreciated.

  2. #2
    Join Date
    Jun 2002
    Posts
    13,531
    Quote Originally Posted by mackmckearney View Post
    Why do some craters seem to come off the screen while others sink into the screen? This is making it quite difficult to distinguish boulders from craters. Any help would be greatly appreciated.
    Haven't read it, but this thread might be of help...

  3. #3
    Join Date
    Jun 2004
    Location
    The Great NorthWet
    Posts
    14,716
    The simple answer, as I understand it, is the the human visual system is conditioned to expect light coming from above, including from the top of a picture. If light comes from the bottom of a picture, it casts a shadow on the lower (in the picture) half of the crater, where it would be cast on a bump if light was from the top. With practice, you can mentally invert the "bumps" into craters. Or just rotate the picture 180 degrees!

    ETA: Here's another old thread, in which I give the same answer! And one from the BA himself.
    Last edited by Trebuchet; 2014-May-05 at 06:04 PM.
    Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

  4. #4
    Join Date
    Jun 2014
    Posts
    3
    I perceive it was something made from the meteorites.

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