Interactive floor project

hi,

i use OF quite sometimes but i am still consider new to this environment. I am a final year student of a Art school and think of doing interactive floor project. :-\ wondering how am i going to start for this project… any tutorial or book to recommend?

If you already use OF you’re probably (at least somewhat) comfortable with c++, IDEs etc, so a good start for your interactive floor could be looking at the OpenCV example in your OF installation.

In this example you’ll learn how to find contours (of a certain size) inside video stream and this kind of operation is backbone of most interactive floors.
I don’t know what you need to achieve for your installation, but you’ll probably want to place your camera on the ceiling and look for the shape of the people below; it will be easier if you use infrared (a modified ps3eye or kinect are cheap, reliable options), because you’ll get cleaner images and you won’t have to worry about visible light conditions.

A very good book to get started in this world is Programming-Interactivity.

thank you for your reply. i will look for the kinect and for the projector, any specify brand or requirement?

the short answer is: no, any projector will do.
the more articulated answer is: is mostly depends on your requirements. Basically the 2 most important variables are light and covered surface.

For light: in my experience if you’re working in an indoor, shady environment, 2500 lumen is going to be enough. (also: in most cases it’s easier and cheaper to make your environment darker/more controlled than to try to create something that will handle every possible condition).

For surface: it’s a combination of factors:

  • if you’re going to project on the floor the first thing to consider is: how much high can I go with the projector? if your vertical space is limited, you should consider a short throw projector (wide lens, focuses and gives you big output on near surfaces). In case of need just remember that you can create “virtual space” and/or change the direction of the projector beam bouncing on angled mirrors.

  • since you’re not using your projector to watch movies, you’ll probably want to go beyond the specs on the box: if your projector’s instructions paper says that its maximum projection size is 3m from a distance of 2.5m, you’ll probably be able to achieve 5m moving it a little more distant; your pixels will be a little bigger, but they will be ok for your needs.

Finally, since you’re creating an interactive floor, your camera and your projector should be calibrated together (ie: if you’re projecting the image captured from the camera, the image of a certain object should fall on the object itself). Since it’s your first time, my suggestion is to keep it simple: if your projector and your camera have a similar fov, placing them one next to the other and adjusting by hand will give you a result good enough for most interactive floor purposes. More complex scenarios involve the development of ad hoc calibration tools (homographies, multi cam stitching, etc…) that allow the user to correctly match what’s captured by the camera(s) with the software’s output.

have fun :wink:

two amendments to nausea’s post:
be aware that most projectors can’t be mounted in a position too much away from the horizontal (e.g. vertically pointing downward) due to cooling requirements. check the manual online before buying, or use a front surface mirror (to avoid a double picture of a regular mirror).
regarding the maximum distance: while it’s ok to go a little farther than the specified max distance, some projectors cannot focus the picture outside of their given distance range.

If you can represent actors as points on the floor for the purpose of your project, I would highly recommend thermitrack, which works off a IR light emmitted by human body, therefore it is not affected by the environment, and is extremely robust –– my installation at a theatre is in a second year running with no glitch.

–8

Hi,

Thanks again for the reply…

naus3a: i will try to look for a 2500 ansi Lu. projector…
bilderbuchi: i will double check on the issue before the purchase…
eight: For the camera, are you referring to this one? http://www.thermitrack.com/- any specify brand you are recommend? by the way for current development phase, i bought the kinect sensor to do the testing… if the thermitrack is not expensive…i dun mind to get thermitrack for further testing…

prue3,

Did you get an evolution in how create a interactive projection floor?
I have no idea how start write the code…
Could you help me?
Thanks

look for opencv, blob detection and choose an IR camera .
almost everything on my site www.pisointeractivo.net was made using those concepts,
actually i used openframworks to create the version 1 of my software later on i moved to c# because my target OS was windows.

so yes its posible and its a lot of fun :smile: