[vtkusers] Problem rotating vtkImageSlice

Sun Aug 28 17:42:59 EDT 2016

I meant DRR "or" MIP (Digitally Reconstructed Radiograph, Maximum Intensity
Projection).

On Sun, Aug 28, 2016 at 3:41 PM, David Gobbi <david.gobbi at gmail.com> wrote:

> Okay, let me try to understand this.  Please let me know if I'm wrong on
> any of the following points.
>
> 1) You have a CT scan, consisting of several slices (I assume around 100
> slices) with uniform spacing.
>
> 2) You have a single XA image.  An XA is a projection image, in contrast
> to CT which is a tomographic image.
>
> 3) You need to find the direction-of-projection through the CT volume such
> that it matches the XA.
>
> This is generally done by creating a DRR a MIP of the CT.  I'm not sure
> how you plan to achieve this by rotating a slice.
>
>  - David
>
> On Sun, Aug 28, 2016 at 3:09 PM, Richard Frank <rickfrank at me.com> wrote:
>
>> I thought I coil rotate the image slice in 3 space as defined here
>>
>> http://www.vtk.org/doc/nightly/html/classvtkImageSlice.html#details
>>
>> Rick Frank
>>
>> On Aug 28, 2016, at 3:42 PM, David Gobbi <david.gobbi at gmail.com> wrote:
>>
>> Then remind me again why you're using vtkImageResliceMapper instead of
>> vtkImageSliceMapper?
>>
>> On Sun, Aug 28, 2016 at 1:23 PM, Richard Frank <rickfrank at me.com> wrote:
>>
>>> I'm just trying to rotate the plane in 3 space, not reslicing...
>>>
>>> Rick Frank
>>>
>>> On Aug 28, 2016, at 3:16 PM, David Gobbi <david.gobbi at gmail.com> wrote:
>>>
>>> If you only had one input slice, then why would you be surprised that
>>> reslicing at 90 degrees gives an output that is only one pixel wide?
>>>
>>> On Sun, Aug 28, 2016 at 12:53 PM, Richard Frank <rickfrank at me.com>
>>> wrote:
>>>
>>>> Hi
>>>>
>>>> I'm using the VTK example which creates an in memory single cyan
>>>> slice.....
>>>>
>>>> Thanks
>>>>
>>>> Rick Frank
>>>>
>>>> On Aug 28, 2016, at 2:42 PM, David Gobbi <david.gobbi at gmail.com> wrote:
>>>>
>>>> Check the extent of the input image to make sure all of the slices were
>>>> loaded.
>>>>
>>>> On Sun, Aug 28, 2016 at 12:37 PM, Richard Frank <rickfrank at me.com>
>>>> wrote:
>>>>
>>>>> Hi David,
>>>>>
>>>>> Sorry about the attachment.
>>>>>
>>>>> Well, I'm pretty far along with my work on this, so I'd like to try
>>>>> the vtkPlane orientation as a solution if possible.
>>>>>
>>>>> using the example code,  If I create a vtkPlane, set its origin to
>>>>> 0,0,0 and set its normal to 1 0 0 (instead of 0,0,1) and call
>>>>>  imageResliceMapper->SetSlicePlane(plane);
>>>>>
>>>>> I see a thin line. Seems correct. If I change the interactor style to
>>>>> Trackball camera, and rotate the camera around it seems the image is only 1
>>>>> unit wide however.
>>>>>
>>>>> Is there something else I need to do to get the image to map to a
>>>>> plane with different orientation?
>>>>>
>>>>> THanks
>>>>> Rick Frank
>>>>>
>>>>> On Aug 28, 2016, at 12:51 PM, David Gobbi <david.gobbi at gmail.com>
>>>>> wrote:
>>>>>
>>>>> Hi Frank,
>>>>>
>>>>> It looks like you are doing a data transformation when you should be
>>>>> doing a view transformation.  Don't rotate the actor if your goal is to
>>>>> rotate the view.  When you rotate the actor, you are changing the
>>>>> relationship between data coordinates and world coordinates.
>>>>>
>>>>> If you want a sagittal view, then you can rotate the view by moving
>>>>> the VTK camera.  The mapper has a method SliceFacesCameraOn() that can be
>>>>> used to make the mapper automatically extract a slice in the correct
>>>>> orientation.
>>>>>
>>>>> Also, please limit the width of inlined images to around 1000 pixels
>>>>> or less.  Large inlined images make your email hard to read on my system (I
>>>>> wish that gmail would auto-shrink oversized inlined images, but
>>>>> unfortunately it displays them full-size, even if they're several times the
>>>>> size of the display).
>>>>>
>>>>>  - David
>>>>>
>>>>> On Sun, Aug 28, 2016 at 9:56 AM, Richard Frank <rickfrank at me.com>
>>>>> wrote:
>>>>>
>>>>>> Hi David,
>>>>>>
>>>>>> Thanks for the reply. I'm still a bit confused about what I've tried
>>>>>> and why it doesn't work....
>>>>>>
>>>>>> So, I have 3 slice views and in the screenshot the Axial View is
>>>>>> lined up appropriately (image position patient is in the correct place, and
>>>>>> each slice is in correct place etc) with the world coordinates by using the
>>>>>> image reslice axis and camera etc to align the DICOM coordinates and the
>>>>>> VTK World coordinates.
>>>>>>
>>>>>> I now want to orient the sagittal slice so that it aligns with the
>>>>>> world coordinates.
>>>>>>
>>>>>> (see screen shots)
>>>>>>
>>>>>>
>>>>>> I believe I need to rotate the slice (if I could rotate the actor)
>>>>>> about Z 90 CCW and then about its new X 0- degrees and then move the camera
>>>>>> about world Y 90 and the roll the camera 90 to get the sagittal voxels
>>>>>> DICOM aligned with the World Coordinates.
>>>>>>
>>>>>> I tried various parameters for the resliceMapper->SetSlicePlane() but
>>>>>> the slice just dissapears off screen somewhere so I must be getting
>>>>>> sometime wrong.
>>>>>>
>>>>>> How would I use the SetSlicePlane to achieve this?
>>>>>>
>>>>>> Thanks
>>>>>>
>>>>>> Rick
>>>>>>
>>>>>> On Aug 27, 2016, at 02:51 PM, David Gobbi <david.gobbi at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>> You should also try vtkImageSliceMapper instead of
>>>>>> vtkImageResliceMapper,
>>>>>> perhaps its behavior will better suit your requirements.
>>>>>>
>>>>>>
>>>>>> On Sat, Aug 27, 2016 at 11:51 AM, David Gobbi <david.gobbi at gmail.com>
>>>>>> wrote:
>>>>>>
>>>>>>> Hi Rick,
>>>>>>>
>>>>>>> You're seeing this because you are doing an out-of-plane rotation on
>>>>>>> an image that has only one slice.  The rotation is around the image origin,
>>>>>>> which (in this case) is at the bottom-left corner of the image.
>>>>>>>
>>>>>>> The vtkImageResliceMapper has a SetSlicePlane() method:
>>>>>>> http://www.vtk.org/Wiki/VTK/Image_Rendering_Classes#vtkImage
>>>>>>> ResliceMapper
>>>>>>> You must rotate this SlicePlane when you rotate the vtkImageSlice.
>>>>>>>
>>>>>>>  - David
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> On Sat, Aug 27, 2016 at 10:54 AM, Richard Frank <rickfrank at me.com>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> Hi,
>>>>>>>>
>>>>>>>> If I build the example
>>>>>>>>
>>>>>>>> VTK/Examples/Cxx/Images/ImageSlice
>>>>>>>> and add
>>>>>>>>
>>>>>>>>  imageSlice->RotateX(1);
>>>>>>>>
>>>>>>>> Which should, I think, rotate the image actor about its X axis by 1
>>>>>>>> degree, I instead get
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> which seems incorrect.
>>>>>>>>
>>>>>>>> I can rotate about Z.
>>>>>>>>
>>>>>>>> Is there something I'm not doing correctly, or is this a bug?
>>>>>>>>
>>>>>>>> I also tried RotateWXYZ(1,1,0,0) and get the same result.
>>>>>>>>
>>>>>>>> This is VTK 7
>>>>>>>>
>>>>>>>> Thanks
>>>>>>>>
>>>>>>>> Rick
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
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