Dear Kilgus,
Thank you very much for your quick reply! I will do an experiment with
default parameters as you suggested. For the third question, I have to say
that I never do any experiment for it and maybe I'm wrong, so I'm sorry I
can not offer any information to prove my opinion. Thank you very much!
Regards,
Deqiang
2013/1/8 Kilgus, Thomas <[email protected]>
> Hi Deqiang,****
>
> ** **
>
> To 1): The current default parameters in the
> mitkToFDistanceImageToXXXFilter are parameters for the PMD CamCube Camera.
> You are absolutely right, that they don’t fit to the Kinect and you have to
> adapt them. In my experience, the Kinect comes with an accurate default
> calibration. You could just use freely available parameters, like the one
> from Nicolas Burrus:
> http://nicolas.burrus.name/index.php/Research/KinectCalibration.
> Attention: We use the stereo calibration from OpenNI. That means the
> distance image is already in the RGB-image-space and you have to use the
> RGB-intrinsics (not the IR-intrinsics!). We are working on a default
> calibration file for all available cameras which would solve this problem.
> Hopefully, we will manage this feature for the next release.****
>
> ** **
>
> To 2): Yes, we use the stereo calibration from OpenNI. Pixel indices
> should be the same, however, only for a default Kinect calibration. Your
> personal Kinect device can be slightly different. This should not be a big
> deal, but is depending on your application and your desired accuracy. ****
>
> ** **
>
> To 3): In principle, you need camera intrinsics to perform 3D
> reconstruction of Time-of-Flight data. I am currently trying to figure out
> whether this is true or not for the Kinect in combination with OpenNI. Do
> you have any information (e.g. URL) to prove your point? I did an
> experiment where I measured a Lego Phantom with the Kinect and compared it
> to ground truth. My results are always better when I used the
> RGB-Intrinsics to reconstruct the 3D surface. Could you tell me how
> exactly you would perform the 3D reconstruction assuming you use OpenNI?
> Looking at the book “Hacking the Kinect“ the reconstruction is performed
> without any intrinsics (see chapter 7, “Moving from depth map to point
> cloud”), however, they are not using OpenNI. I could not find any good
> source, yet, which tells if OpenNI needs this conversion or not. I just
> have better results when I use the intrinsics. Any help of yours is
> appreciated.****
>
> ** **
>
> (see for “Hacking the Kinect”
> http://books.google.de/books?id=IftkzqRjbO4C&pg=PA130&lpg=PA130&dq=kinect+depth+image+to+point+cloud+pinhole+camera+model&source=bl&ots=XuWzUbeny6&sig=3kAaHm5_Z02Yj3Ft7PybAJauYOM&hl=en&sa=X&ei=pue4UMKtLof1sgar-YCgBQ&ved=0CEgQ6AEwBA#v=onepage&q&f=true
> )****
>
> ** **
>
> Regards,****
>
> Thomas****
>
> ** **
>
> ** **
>
> Thomas Kilgus****
>
> German Cancer Research Center (DKFZ)****
>
> Div. Medical and Biological Informatics ****
>
> Junior group: Computer-assisted Interventions (E131)****
>
> Im Neuenheimer Feld 280****
>
> 69120 Heidelberg, Germany****
>
> Phone: +49(0) 6221-42-3545****
>
> ** **
>
> ** **
>
> *From:* Deqiang Xiao [mailto:[email protected]]
> *Sent:* Dienstag, 8. Januar 2013 14:04
> *To:* [email protected]
> *Subject:* [mitk-users] Camera intrinsic parameters in
> mitkToFDistanceImageToPointSetFilter.cpp of ToFProcessing module****
>
> ** **
>
> Dear all,****
>
> ** **
>
> My current work is based on MITK ToFUtil with kinect for windows and I
> have read most part of related code in ToFUtil, then I get three question
> about this plug-in:****
>
> ** **
>
> 1) Where are the camera intrinsic parameters in
> mimitkToFDistanceImageToPointSetFilter.cpp\mitkToFDistanceImageToSurfaceFilter.cpp(..\MITK\Modules\ToFProcessing\)
> from? If this camera intrinsic parameters are not fit for kinect, the
> calibration for IR camera of kinect is need or not?****
>
> ** **
>
> 2) Do rgb image and ir image have been calibrated in ToFUtil?(If they are
> calibrated, two pixels which have the same coordinate index in rgb image
> and ir image correspond the same point in physical space)****
>
> ** **
>
> 3) Why the camera intrinsic parameters are used in 3D reconstruction from
> depth image?(In my opinion, 3D reconstruction based on depth image doesn't
> need camera intrinsic parameters) ****
>
> ** **
>
> Any help is appreciated!****
>
> ** **
>
> Regards,****
>
> Deqiang****
>
> ** **
>
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