create vertical line picture ilda file

I want to create an effect with my laser projector that I once saw done with a vertical string of LED's

The effect was a string of LED lights that to the casual observer simply looked like they were flickering. When you turned your head side to side you would see an image, in the case of this display the mona lisa. Basically your head is doing the horizontal scanning.

This effect should be possible if you create a rastor image and turn off the horizontal scanning mirror. It should look like a single vertical laser line that is flickering, but looks like an image when you turn your head side to side.

I found some software to create a rastor ild file, but I don't know how to turn off the horizontal scanning.

I can think of ways of simply disconnecting the signal, but I would really like to do this such that any ild player sofware can reproduce this and doesn't require hardware changes.

Just set your x scale to 0.

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Originally Posted by crap2020

I want to create an effect with my laser projector that I once saw done with a vertical string of LED's

The effect was a string of LED lights that to the casual observer simply looked like they were flickering. When you turned your head side to side you would see an image, in the case of this display the mona lisa. Basically your head is doing the horizontal scanning.

This effect should be possible if you create a rastor image and turn off the horizontal scanning mirror. It should look like a single vertical laser line that is flickering, but looks like an image when you turn your head side to side.

I found some software to create a rastor ild file, but I don't know how to turn off the horizontal scanning.

I can think of ways of simply disconnecting the signal, but I would really like to do this such that any ild player sofware can reproduce this and doesn't require hardware changes.

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Yes, where would you make that setting in the ilda file? I don't have a way to do that when I create the rastor image. Perhaps some ilda playing software can do that, but I don't want everything I display to have the x off. Can you somehow edit the ilda file directly to do this?

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"Just set your x scale to 0."

Not exactly. You have the right idea, but you need to have absolute control over the order that each element of every letter is drawn.

I thought about this a long time ago. I've seen the LED sticks and I think it's one of the neatest, almost subliminal, optics tricks I've seen a a while.

I have some frames that are like tight spirals and stuff. They don't look like much when you look straight at them. I always tell people, look to the far left of the screen and then dart your eyes to the far right. Did you see that? Pretty cool! :)

It really points out the fact that laser images are made of a single moving dot. And, even though animations are frame based, every frame takes time to draw, unlike a motion picture film or video, where the entire frame is rendered all at once.

Do this in your laser projector software.

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Originally Posted by crap2020

Yes, where would you make that setting in the ilda file? I don't have a way to do that when I create the rastor image. Perhaps some ilda playing software can do that, but I don't want everything I display to have the x off. Can you somehow edit the ilda file directly to do this?

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Good point. You may need to do this as a series of frames.

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Originally Posted by james

quote:
"Just set your x scale to 0."

Not exactly. You have the right idea, but you need to have absolute control over the order that each element of every letter is drawn.

I thought about this a long time ago. I've seen the LED sticks and I think it's one of the neatest, almost subliminal, optics tricks I've seen a a while.

I have some frames that are like tight spirals and stuff. They don't look like much when you look straight at them. I always tell people, look to the far left of the screen and then dart your eyes to the far right. Did you see that? Pretty cool! :)

It really points out the fact that laser images are made of a single moving dot. And, even though animations are frame based, every frame takes time to draw, unlike a motion picture film or video, where the entire frame is rendered all at once.

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LaserBoy gives you absolute control over the order in which elements are arranged and drawn. You can take a single frame and explode it into a frame set with each frame containing a single lit segment. You can even control the direction that each lit segment is stroked. Then you can re-order those frames and glue them back together into a single frame. You could design the frame in 2D and also use LB to reduce the result down to 1D. Probably the best way to do it is to leave it 2D and just show it from the side! If you want to just make an ILDA file that will open in some other projection system, you could rotate the 2D frame and save it as 3D. That way you would always be able to read it on a computer screen. :)

James. :)

I haven't used LaserBoy but it sounds like something I need to look into. I was thinking I might need to do this as a set of frames, but ultimately I am just looking to get this effect.

I do think it is a very subliminal effect, and it's one that you should be able to reproduce even on a tv or computer screen or with a standard video projector, although with a somewhat diffent method.

LaserBoy is very different than any other laser show application out there. So be ready for that!

http://laserboy.org/code/LaserBoy_2012_05_03.zip

I really like to chat with people about it over Skype. A caller can open LB and share that portion of the screen with me in a video call and then we can both see what's going on and I can demonstrate it.

James. :)

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 for every X. 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. :)

Why not just use a vertical row of laser diodes?

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Originally Posted by james

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. :)

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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.

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?

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.

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

James. :)