Tuesday, February 08, 2005

Here are some facts about why things are the way they are:
1. Most of the energy in the frequency spectrum of a natural signal (noise, image, etc.) is at the low frequencies, and it drops off as a function of 1/f. This is because a big thing can have smaller things on it (like a field can have grass and rocks on it) but a small thing can't have bigger things on it. And also, as something gets smaller by x amount (i.e. * it by 1/x), its surface area gets another 1/x smaller (i.e. * it by 1/x squared). So the first 1/x is scaling wavelength, the inverse of frequency, and the second 1/x is like the potential energy at x (yes, at itself). Amazing!

So things have to be that way.

2. Most of the energy in natural scenes is at horizontal, and then vertical, orientations. This is because of gravity. Gravity makes things flat, causing horizons and other horizontal contours, and also vertical contours if you're up close and looking down on it. Living things, for one, contribute a lot to vertical energy. Otherwise (if they were dead) they'd be flat. So, on earth at least, you have tons of vertical symmetry, because they proper way for a thing to be is upright. Trees are vertical, people are vertical, cats are vertical, etc. So things also have to be that way.

3. Your brain already knows these things, even if you didn't know it knew. It's ready to process things in the environment according to regularities that it expects to find all over the place. This saves you time and energy, so you can expend it getting better at playing video games.

Now you've learned something! Tell everyone you know! But not engineers, they'll get picky on you. I hope no engineers are reading this.


  1. Luckily, writing grad students aren't picky, and I say bravo! for telling me why things are the way they are. Now I don't have to write anymore.

  2. I'm an engineer, so I can't say anything more than this.

  3. it looks like all i've done is cause harm by writing more words on this website thing. never again. i should have learned the last time.

  4. Nah! I'm an engineer, and I agree with what you said about engineers being picky. Just like elementary particles or alaskan crab fishing: it's in the encyclopedia.

  5. I'm just commenting to comment.

    "witty reply to engineer thing"

    "wacky joke about Andrew's Post and his name change."


  6. andrew keeps on stopping me (from) reading it (loudly),555~~~