[vtkusers] getting a blank volume when trying to perform an x-ray projection in Java

[David Gobbi]

Hi Mark,

The vtkImageProjection filter provides averaging as its default
option.  As far as I know, the vtkImageRayCastMapper doesn't
even provide averaging as an option.

Setting the reslice transform shouldn't be too bad.  Take a look
at vtkPerspectiveTransform, it is the transform that the camera
uses and has all the necessary methods for creating a perspective
view transform.

  David


On Wed, Jan 5, 2011 at 10:14 AM, Mark Roden <mmroden at gmail.com> wrote:
> Hi David,
>
> Thanks for this-- I'll take a look.  I definitely need the ability to
> rotate freely, so having to write my own controller over the reslice
> could be extremely painful.
>
> What kinds of projections?  I really want an average intensity
> projection, but I can't really see how to do that now.
>
> Thanks,
> Mark
>
> On Tue, Jan 4, 2011 at 1:48 PM, David Gobbi <david.gobbi at gmail.com> wrote:
>> Hi Mark,
>>
>> For projections, I added a new filter called vtkImageProjection to
>> vtk-devel that will create a projection image from a 3D image.  It
>> isn't picky about data types, it will take whatever is given.  But it
>> has two caveats:
>> 1) it is a filter, not a mapper, so you have to use vtkImageActor to
>>   display the result on-screen
>> 2) It only does x, y, and z projections so it must be preceded by
>>   vtkImageReslice if other perspectives are needed
>>
>> I don't know if it will be useful to you, but just in case.
>>
>>  David
>>
>