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Thread: create vertical line picture ilda file

  1. #11
    swamidog's Avatar
    swamidog is offline Jr. Woodchuckington Janitor III, Esq.
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    Why not just use a vertical row of laser diodes?



    Quote Originally Posted by james View Post
    Actually... after thinking about this a bit more and actually trying an experiment, I have come to the conclusion that....

    No. This is not possible!

    The one critical difference between the LED stick and the laser projector is that the LED stick can have any number of LEDs lit at any given time. The laser projector will always be one dot. That means that the only thing you can draw, with the assumption that the X axis is fast, linear time, would be a function f(x) that could have one and only one Y value. You could never have a real "figure" of an image or a line that loops back and overlaps itself. You could only have a single line through X that meanders up and down in Y and might have gaps in it with blanking.

    Oh well.

    James.
    suppose you're thinkin' about a plate o' shrimp. Suddenly someone'll say, like, plate, or shrimp, or plate o' shrimp out of the blue, no explanation. No point in lookin' for one, either. It's all part of a cosmic unconciousness.

  2. #12
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    Yes, I see your point, although I am not yet convinced that somethign like this isn't possible (without multiple lasers), I need to do some more mental expirments, and perhaps some real ones too.

  3. #13
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    Maybe if you scan the line really fast, and let it sweep up and down a few times before going to the next segment of the image?

  4. #14
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    I was thinking that basically since you can only put up one point at a time things will be off a distortion of sorts. While I understand things will be distorted, I am not convinced yet that you can't compensate for this, but it may end up being the case.

    Since the laser scanner goes both up and down drawing a vertical line you are basically oscillating the mirror up and down in a sign wave pattern. This should give you some sort of circle or oval if you turn your head depending on the scan speed. The faster you can oscillate the longer the oval.

    I don't know about just scanning up and down very fast, although I guess if it was fast enough the distortion would be less.

  5. #15
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    Think about it like this: A Laser projector, with scanners is a vector scope. If you add a local sweep oscillator to a vector scope, you get an oscilloscope. The illusion you are trying to achieve is the same thing as an oscilloscope, but you only get one sweep across the X axis, every time you dart your eyes from one side of the screen to the other.

    In Cartesian Math (something I have loved and studied much of my life) we are looking at coordinates based on X and F(X).

    http://en.wikipedia.org/wiki/Cartesi...rdinate_system

    That's it. Both axis depend on each other. This is the definition of an "onto" function.

    http://en.wikipedia.org/wiki/Onto_function

    If you want to draw figures that have lines that loop back on themselves and form shapes, you need to have both the X and Y values independent of each other in Parametric equations.

    http://en.wikipedia.org/wiki/Parametric_equation

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