[Insight-users] Problem with DRR generation

[Luis Ibanez]

Hi Jian,

Looking at the Code of the DigitallyReconstructedRadiograph1.cxx
it seems that it is missing to take the image origin into account.


If your image has an origin different than zero, the computation
of the image center will be incorrect.


We just committed a fix for this issue to the CVS repository.
You may want to update your CVS checkout (if you have one)
or you can apply the same corrections to your local code.


The modifications can be found at:
http://www.itk.org/cgi-bin/viewcvs.cgi/Examples/Filtering/DigitallyReconstructedRadiograph1.cxx?root=Insight&sortby=date&r2=1.15&r1=1.14



   Please let us know if you find any problems,



      Thanks


         Luis



---------------
Jian Wu wrote:
> Dear ITK users:
> 
> I'm wondering if anyone have generated correction DRRs using the example 
> programs GenerateProjection.cxx or DigitallyReconstructedRadiograph1.cxx.
> 
> I ran both codes using the parameters and the image given in the 
> README.txt file. But the generated DRRs appear to have a different 
> projection and image center than I expected.
> I also tried to simply the test data in 
> DigitallyReconstructedRadiograph1.cxx. Instead of using the orignal 
> cubic structure, I constructed a 61x61x61 3D image with a single point 
> at the center of the image. The resulting DRR has a point centered at 
> pixel index (81, 81). The DRR has the size of 501x501, and the point is 
> supposed to be at the center of the image. I can't figure out how the 
> projection works. I really wish the projection geometry were better 
> documented.
> 
> When real CT data sets were used, the objects in the output DRRs appear 
> to have been shifted toward the left-bottom corner of the images. I 
> searched the emails that have been posted before. It appears someone has 
> pointed out the problem before. However, I did not find any answers to 
> the question. By the way, the IntensityBased2D3DRegistration.cxx example 
> code does not work. I have posted the problem a couple of days ago.
> 
> Someone help me out please!
> 
> Jian Wu
> 
> 
> _______________________________________________
> Insight-users mailing list
> Insight-users at itk.org
> http://www.itk.org/mailman/listinfo/insight-users
> 
>