| ARToolKit | Mailing List Archive |
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| From: | "tobes" <tobiaseble@g .....> | Received: | Jan 11, 2007 |
| To | <artoolkit@h ..................> | ||
| Subject: | ARToolkitPlus: get undistorted and threshold image | ||
This is a multi-part message in MIME format. ------=_NextPart_000_0208_01C73582.446E5310 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi...=20 im imterested in how to access the undistored and the threshold image. regards, Tobi ------=_NextPart_000_0208_01C73582.446E5310 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=3DContent-Type content=3D"text/html; = charset=3Diso-8859-1"> <META content=3D"MSHTML 6.00.2800.1106" name=3DGENERATOR> <STYLE></STYLE> </HEAD> <BODY bgColor=3D#ffffff> <DIV><FONT face=3DArial size=3D2>Hi... </FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2>im imterested in how to access the = undistored and=20 the threshold image.</FONT></DIV> <DIV><FONT face=3DArial size=3D2></FONT> </DIV> <DIV><FONT face=3DArial size=3D2>regards, = Tobi</FONT></DIV></BODY></HTML> ------=_NextPart_000_0208_01C73582.446E5310-- |
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| From: | Daniel Wagner <daniel@i ...............> | Received: | Jan 12, 2007 |
| To | ARToolKit Mailinglist <artoolkit@h ..................> | ||
| Subject: | Re: ARToolkitPlus: get undistorted and threshold image | ||
tobes wrote: > im imterested in how to access the undistored and the threshold image. There is no undistorted or thresholded image ever present in memory. To save performance and memory, ARToolKit/Plus thresholds pixels on the fly and never creates a complete thresholded copy of the image. Same goes for undistortion: Only those pixels that need to be undistorted (those along the edges of the markers) are undistorted. Again, only the undistorted position is stored but not the pixel itself in an image. If you want to undistort an image with ARTK you can call the undistortion function for every pixel. You should be prepared though to work with sub-pixel precision (at least linear filtering) to get good results (but then i have no idea what you need this for...) Daniel |
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| From: | Daniel Wagner <daniel@i ...............> | Received: | Jan 12, 2007 |
| To | ARToolKit Mailinglist <artoolkit@h ..................> | ||
| Subject: | Re: ARToolkitPlus: get undistorted and threshold image | ||
tobes wrote: > about the undistortion image. I would like to match real geometry > to virtual geometry. for this i can eiter distort my virtual model or > undistort the image. Since you'll probably use texturing for drawing the camera feed as a video background anyhow, i'd rather undistort the image using these texturing capabilities. Performing a high quality undistortion on the CPU would be very slow, while graphics cards are generally really good at distorting images (textures)... :) If bilinear filtering is enough then you only need to subdivide the video background quad and move the texture coordinates accordingly. If you need higher quality (cubic interpolation) then you'll probably have to use shaders. There should be lots of references on this in all those GPU programming papers and books released in the last few years. Daniel |
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