I’m attempting to develop an application which requires that the orientation of a projector is determined by tags attached to the display surface, and used to predistort the image so it appears undistorted on the display surface. I am using ARTK+Tracker, and have got this working successfully, and I gather that the quickest way to predistort an image for projection on the surface is to use Homography, but I’m having real issues understanding what needs to happen between the two.
Homography obviously needs four points from which to calculate the transform and I’m struggling to work out how to pull these points out of the matrix generated from ARTK+Tracker. I thought there might be a way by using VertexBuffer on a Grid object transformed by the ARTK+ node through SetMatrix, but I cannot find a way of transforming an EX9.Geometry such as Grid.
I feel like this should be a really straightforward thing to do, I just don’t have the knowledge to do it. I’m certain that someone here does!
I’m attempting to develop an application which requires that the orientation of a projector is determined by tags attached to the display surface, and used to predistort the image so it appears undistorted on the display surface. I am using ARTK+Tracker, and have got this working successfully, and I gather that the quickest way to predistort an image for projection on the surface is to use Homography, but I’m having real issues understanding what needs to happen between the two.
Homography obviously needs four points from which to calculate the transform and I’m struggling to work out how to pull these points out of the matrix generated from ARTK+Tracker. I thought there might be a way by using VertexBuffer on a Grid object transformed by the ARTK+ node through SetMatrix, but I cannot find a way of transforming an EX9.Geometry such as Grid.
I feel like this should be a really straightforward thing to do, I just don’t have the knowledge to do it. I’m certain that someone here does!
hey… im have the same idea that you have on my mind, i was thinking of using 4 leds and a wiimote isted of ar… but anyway we have the same idea, how to manipulate homographi to get the angle we are looking for.
how to you have the output of artk traker ? like a angle, like a vector ? please let me know im tring to do the same
i’t a good idea, and probably it’s better to use weemote instead of artoolkit. i think it is more stable, more efficient, and you have directly the points coordinates (artoolkit gives a trnsform)
the output of homography is a perspecitve transformation
and you should get the same transformation from artk (at least i think so), so why bother with homography?
vikor is absolutely right, thats the whole point of the ARTK+. just connect the projection transform to the renderer and the world transform to a quad. then the quad will match the marker.
if you are tracking 4 markers, one for each corner, you can use * (3d) or ApplyTransform to get the center of the markers.
but tom what if you want to control a camera composition ( xº and yº ) from the angle of a marker ?
i am not exacly shure what you want to do?