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Hi everyone,
I've got my ARToolkitPlus application working with the markers pasted onto
10cm^3 cubes. When I render 3D cubes over the video image, I noticed the
overlay error increases as I move towards the boundaries of the image. I'm
assuming this is due to the radial distortion.
My question is: Do most of you undistort the video image or do you distort
the OpenGL model (which would imply a nonlinear transformation)? Can anyone
point towards any code that does this? (either way)
Regards,
Victor
-----Original Message-----
From: owner-artoolkit@h ..................
[mailto:owner-artoolkit@h ..................] On Behalf Of Victor
Ng-Thow-Hing
Sent: Monday, May 14, 2007 5:01 PM
To: artoolkit@h ..................
Subject: Matlab camera calibration parameters for ARToolkitPlus
Hi Everyone,
I recently performed a camera calibration with the Matlab Calibration
toolkit for an Opteon camera. When creating a new camera calibration file
from this data, the ARToolKitPlus web site states:
The ASCII-file containing the camera calibration parameters should look as
follows:
[line1]: ARToolKitPlus_CamCal_Rev02
[line2]: xsize ysize cc_x cc_y fc_x fc_y kc1 kc2 kc3 kc3 kc5 kc6 iter
xsize, ysize: calibrated frame dimensions (does not have to match the frame
dimensions at runtime)
cc_x, cc_y: principal point location (in pixels)
fc_x, fc_y: focal length (in pixels)
kc1..kc6: radial/tangential distortion coefficients (kc6 currently not in
use)
iter: number of iterations for distortion compensation
My question is: For the kc1..kc6, I only have 5 distortion parameters from
the Matlab calibration. Should I assume kc6 is 0?
I'm not sure what the iter (number of iterations for distortion
compensation) value should be? Is this a specific parameter of the Lens
Undistortion
lookup table in ARToolkitPlus? I'm not sure how to interpret the meaning of
iter.
Regards,
Victor
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<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN =
class=3D432264207-15052007>Hi=20
everyone,</SPAN></FONT></DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN =
class=3D432264207-15052007>I've=20
got my ARToolkitPlus application working with the markers pasted onto =
10cm^3=20
cubes. When I render 3D cubes over the video image, I noticed the =
overlay error=20
increases as I move towards the boundaries of the image. I'm assuming =
this is=20
due to the radial distortion.</SPAN></FONT></DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN=20
class=3D432264207-15052007></SPAN></FONT> </DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN =
class=3D432264207-15052007>My=20
question is: Do most of you undistort the video image or do you distort =
the=20
OpenGL model (which would imply a nonlinear transformation)? Can anyone =
point=20
towards any code that does this? (either way)</SPAN></FONT></DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN=20
class=3D432264207-15052007></SPAN></FONT> </DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN=20
class=3D432264207-15052007>Regards,</SPAN></FONT></DIV>
<DIV><FONT face=3DArial color=3D#0000ff size=3D2><SPAN=20
class=3D432264207-15052007>Victor</SPAN></FONT></DIV>
<BLOCKQUOTE dir=3Dltr style=3D"MARGIN-RIGHT: 0px">
<DIV></DIV>
<DIV class=3DOutlookMessageHeader lang=3Den-us dir=3Dltr =
align=3Dleft><FONT=20
face=3DTahoma size=3D2>-----Original Message-----<BR><B>From:</B>=20
owner-artoolkit@h ..................=20
[mailto:owner-artoolkit@h ..................] <B>On Behalf Of =
</B>Victor=20
Ng-Thow-Hing<BR><B>Sent:</B> Monday, May 14, 2007 5:01 =
PM<BR><B>To:</B>=20
artoolkit@h ..................<BR><B>Subject:</B> Matlab camera =
calibration=20
parameters for ARToolkitPlus<BR><BR></FONT></DIV>
<DIV><FONT face=3DArial size=3D2><SPAN =
class=3D829275723-14052007></SPAN>H<SPAN=20
class=3D829275723-14052007>i Everyone,</SPAN></FONT></DIV>
<DIV><FONT face=3DArial size=3D2><SPAN =
class=3D829275723-14052007></SPAN><SPAN=20
class=3D829275723-14052007></SPAN>I<SPAN class=3D829275723-14052007> =
recently=20
performed a camera calibration with the Matlab Calibration toolkit for =
an=20
Opteon camera. When creating a new camera calibration file from this =
data, the=20
ARToolKitPlus web site states:</SPAN></FONT></DIV><FONT face=3DArial=20
size=3D2><SPAN class=3D829275723-14052007></SPAN>
<DIV><BR><FONT face=3D"Times New Roman" size=3D3>The ASCII-file =
containing the=20
camera calibration parameters should look as follows: <BR>[line1]:=20
ARToolKitPlus_CamCal_Rev02 <BR>[line2]: xsize ysize cc_x cc_y fc_x =
fc_y kc1=20
kc2 kc3 kc3 kc5 kc6 iter <BR><BR>xsize, ysize: calibrated frame =
dimensions=20
(does not have to match the frame dimensions at runtime) <BR>cc_x, =
cc_y:=20
principal point location (in pixels) <BR>fc_x, fc_y: focal length (in =
pixels)=20
<BR>kc1..kc6: radial/tangential distortion coefficients (kc6 currently =
not in=20
use) <BR>iter: number of iterations for distortion compensation =
</FONT></DIV>
<DIV><FONT face=3D"Times New Roman" size=3D3></FONT> </DIV>
<DIV><FONT face=3D"Times New Roman" size=3D3></FONT> </DIV>
<DIV><SPAN class=3D829275723-14052007><FONT face=3D"Times New Roman" =
size=3D3>My=20
question is: For the kc1..kc6, I only have 5 distortion parameters =
from the=20
Matlab calibration. Should I assume kc6 is 0?</FONT></SPAN></DIV>
<DIV><SPAN class=3D829275723-14052007><FONT face=3D"Times New Roman"=20
size=3D3></FONT></SPAN> </DIV>
<DIV><SPAN class=3D829275723-14052007>I'm not sure what the iter =
(number of=20
iterations for distortion compensation) value should be? Is this a =
specific=20
parameter of the Lens Undistortion </SPAN></DIV>
<DIV><SPAN class=3D829275723-14052007>lookup table in ARToolkitPlus? =
I'm not=20
sure how to interpret the meaning of iter.</SPAN></DIV>
<DIV><SPAN class=3D829275723-14052007></SPAN> </DIV>
<DIV><SPAN class=3D829275723-14052007>Regards,</SPAN></DIV>
<DIV><SPAN=20
class=3D829275723-14052007>Victor</SPAN></FONT></DIV></BLOCKQUOTE></BODY>=
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