Blog

Fiducials

Written by on 7th February 2012 in Portals, Thoughts with Leave a comment

I’ll admit I have a bit of an issue with QR codes and AR markers. My main problem with them is that they’re pretty ugly, and primarily designed to be looked at by computers and not people. I remember when I first saw an augmented reality demo. Printed out a little piece of paper, looked at it through my computer, and a little CG guy showed up on the marker. I think this was 2008 or so. I was pretty impressed then, but the novelty wore off pretty quickly. I think it comes back to this idea of immersion. From the Friends on Play podcast I listened to a few months ago there was this little nugget of insight: ”Things that don’t have a direct corollary in the real world kill immersion.” It’s not that everything has to be based on a real world thing exactly. But it’s when things seem especially out of place or  particularly “un natural” within the context of the world we’re in that we sort of break from the experience, and I think that’s what happens when I see a lot of AR type things. Even if my “mirror” image (via the webcam) shows a little monster in my hand, when I look down at my hand all I see is a bunch of ugly squares.

Of course this is a mini rant that just leads up to the fact that I think I might have to use markers for my project too, but hopefully it’s in a way that doesn’t break that feeling of immersion as much. Basically after some of the earlier computer vision experiments and after talking about my dilemma with Andrew it seems that the best way to track things in the box is to basically build a mini “touch table” inside the box, where the markers can exist on the bottoms of my objects. This way the main cameras don’t see them, although in the current lighting, you can see the “base” under the object which sort of ruins the compositing. But when lit properly the white sort of gets keyed out.

I’ve been doing some material / scale tests. Unfortunately it seems that the markers need to be fairly large in order to be picked up by the camera, especially when there’s a layer of velum+plexi between the camera and the marker. The camera also needs to be quite a bit a way from the table top. And of course I have the added issue of having lighting on both sides of the “table top” whereas most “reactable” style things have projection on the bottom and the environment is best dark. I don’t mind this. In fact I’m glad that my project can exist in an environment with lights. (I’m a little tired of looking at dark silhouettes in front of projections..) It just means there’s another set of issues to be dealt with.

So this sort of means I’ll be rebuilding my light boxes to accomodate for more space between the “table” and the camera. Camera wise, I think I’ll be ordering the unibrain firewire cameras with the interchangeable lens. I got one of the fire-i web cams to play with first, thinking i might be able to use it for the “main” cameras. But the color and image quality just isn’t that great which means it doesn’t key out very cleanly. But as a camera that’s suppose to be an eye for a computer it’s pretty great, plus i can get the version with a remote ccd, making the camera footprint smaller. I can also control camera exposure and all those settings when I’m within the reactivision software. I’m learning a lot about cameras. Anyways, the video below is just me proving to myself I can use the fiducials…

Leave a Reply





You can use these tags: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>