raytracing a point cloud to generate perspective projection

[bobsta]

I have just got started with vtk, having tried out other geometry processing software tools. I wish to generate a 2d perspective projection from a 3d point cloud. The points are extracted from a DICOM RT Structure Set and represent anatomical structures comprising a plurality of closed polygons each polygon having a number of points (x,y,z, tuples). I need to determine a projection of the structures on an image plane. More specifically I would like to write a binary mask file at the image plane where a "0" indicates that the bixel is outside the particular structure, and "1" indicates that the bixel is inside the structure.

I need to do this for 5-10 structures generating up to 180 projections (i.e. the camera/scene rotates in 2degree steps). Attached is an unprocessed file (no processing of points e.g. outlier removal/unoriented normal removal) has been performed. Furthermore the determination of the projection should be performed quickly (max 1 minute for all projections of all structures, worst case 1800)), since post processing of the binary masks is required by other software.

Any assistance would be gratefully appreciated.


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[Jothy]

I don't really understand your problem, but you can have a look at

http://www.cmake.org/Wiki/VTK/Examples/SimpleOperations/ProjectPointPlane

and also, you can use camera settings to project the points in the scene at a given distance.Something like this

Renderer.GetActiveCamera().SetPosition([0,0,1000])
 Renderer.GetActiveCamera().SetFocalPoint(0,0,0)
 Renderer.GetActiveCamera().Pitch(90)


Jothy

On Tue, Aug 3, 2010 at 2:28 PM, <[hidden email]> wrote:

I have just got started with vtk, having tried out other geometry processing software tools. I wish to generate a 2d perspective projection from a 3d point cloud. The points are extracted from a DICOM RT Structure Set and represent anatomical structures comprising a plurality of closed polygons each polygon having a number of points (x,y,z, tuples). I need to determine a projection of the structures on an image plane. More specifically I would like to write a binary mask file at the image plane where a "0" indicates that the bixel is outside the particular structure, and "1" indicates that the bixel is inside the structure.

I need to do this for 5-10 structures generating up to 180 projections (i.e. the camera/scene rotates in 2degree steps). Attached is an unprocessed file (no processing of points e.g. outlier removal/unoriented normal removal) has been performed. Furthermore the determination of the projection should be performed quickly (max 1 minute for all projections of all structures, worst case 1800)), since post processing of the binary masks is required by other software.

Any assistance would be gratefully appreciated.


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[David Doria-2]

On Tue, Aug 3, 2010 at 10:29 AM, Jothy <[hidden email]> wrote:

> I don't really understand your problem, but you can have a look at
>
> http://www.cmake.org/Wiki/VTK/Examples/SimpleOperations/ProjectPointPlane
>
> and also, you can use camera settings to project the points in the scene at
> a given distance.Something like this
>
> Renderer.GetActiveCamera().SetPosition([0,0,1000])
>  Renderer.GetActiveCamera().SetFocalPoint(0,0,0)
>  Renderer.GetActiveCamera().Pitch(90)
>
>
> Jothy
>

You might also want to look at
http://www.cmake.org/Wiki/VTK/Examples/PolyData/PerspectiveTransform

Thanks,

David
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