After playing around with blob detection and somehow not getting it fast enough a neat little solution came up from Emil Korngold. Using the built in Adobe function ‘getColorBoundsRect’ for the BitmapData object is so much faster looking for ‘Blobs’. (Thanks! I had a look at that when starting and then forgot all about it. Sometimes the simple things are just too far away).
To get a usable result when detecting motion it is good to apply filters and thresholds. This reduces noise and errors when looking for the bounds of a given color. This example is based on the ‘Focus’ demo files provided by Papervision3D.
Click here to have a look at the result. Enjoy!
The interesting part of the code:
private function loop(e:Event):void
{
//bitmap containing difference between last & this frame
newBmd.draw(input);
newBmd.applyFilter(newBmd,bounds,topLeft,filter);
newBmd.draw(oldBmd,null,null,BlendMode.DIFFERENCE);
newBmd.threshold(newBmd,bounds,topLeft,">",0xFFAAAAAA,0xFFFFFFFF); //remember bitmap for next time round
oldBmd.draw(input);
oldBmd.applyFilter(oldBmd,bounds,topLeft,filter);
//now get bounds of a given color...
var newBound:Rectangle = newBmd.getColorBoundsRect(m,c,true);
//now use the newBound to move something...
}Hope this is of any use to someone…
3 Comments. Leave a comment too
May 6, 2008
Nice work mate. Runs smooth.
I like the fact that you don’t have to do a selection first, and think I’ll rework mine to achieve the same. Thanks!
May 8, 2008
Hi. Great blog. This is fantastic. I do quite a lot of stuff with webcams and motion detection. I’ll definitely use this at some stage. Don’t worry though, I’ll link back to you.
November 14, 2008
well it will me fantastic for look an object around …
just moving the head.