Projecting from above with a game that works via Shadows

[Kelemvor]

I don't even know where to begin to post this so hopefully someone here might know what I'm talking about.

In our local mall(s) they have a place for kids to play. The way it works is there's a projector in the ceiling that shines down onto an area on the floor. It just shows bubbles or balls or other things like that. Kids then run around on the projected area and wherever they go, it interacts with what's being projected by moving the things around.

It works by seeing the shadows or the kids on uses that to make bubbles pop or balls bounce around or things like that.

I'm assuming it works via a Webcam or something that shines down and reads the pictures and where the kids are.

ANyone have any idea how this works or what it's called or anything? My daughter loves playing there and since I have a projector, webcam, etc, I thought it'd be ool to rig something like this up at home.

Thanks for any information anyone might have.

 

[BladeVenom]

Sounds like a big Eye Toy.

 

[soccerballtux]

Mall north of Atlanta had one of those I played on.

Then I realized how this is bad design, because if you can't see the screen you can't play it, and yet to play it you have to block a portion of the image lol...

I believe one way would yes be a webcam; what you do is pass the webcam frames/images through a digital filter; the filter is the source image that you are sending to the projector. Then you're going to be left with only visual data in the areas the children are, as the rest of the image got filtered out. Then you can use this in your game program, ie the game looks for non zero values of groups of pixels of a sufficient magnitude; when it finds them, you know you have data there and not just noise (this is what the "of significant magnitude" is for-- non zero value, that is very close to zero). Then you could program the game (say it's bubbles) to try to move away from any area that is inside this disturbance-- "non zero" area of the image.

There are other ways of doing this I'm sure, but this would probably be one.

 

[Kelemvor]

I was hoping there was some software already out there that I could just use. But didn't know if that's how they did it (webcam + projector) or something else.

 

[Leros]

I saw a device kind of like that. You drove a remote control car around and the ground got painted behind it.