[Rtk-users] Parker weighting

[Shiras Abdurahman]

Drear Simon,

I generate the geometry with system geometry parameters and using
AddProjection method.

Here is the code


rtk::ThreeDCircularProjectionGeometry::Pointer rtk_sys_geometry_;
rtk_sys_geometry_ = rtk::ThreeDCircularProjectionGeometry::New();
for (uint16_t proj_index = 0; proj_index < num_projections_; proj_index++)
{
rtk_sys_geometry_->AddProjection(rtk_geom_params_.at(proj_index).sid_mm,
rtk_geom_params_.at(proj_index).sdd_mm,
rtk_geom_params_.at(proj_index).gantry_angle_deg,
rtk_geom_params_.at(proj_index).proj_offset_x_mm,
rtk_geom_params_.at(proj_index).proj_offset_y_mm,
rtk_geom_params_.at(proj_index).out_plane_angle_deg,
rtk_geom_params_.at(proj_index).in_plane_angle_deg,
rtk_geom_params_.at(proj_index).src_offset_x_mm,
rtk_geom_params_.at(proj_index).src_offset_y_mm);
}

 And then write to xml file.

Shiras



On Tue, Dec 8, 2015 at 9:23 AM, Simon Rit <simon.rit at creatis.insa-lyon.fr>
wrote:

> Hi,
> rtkfdk.cxx just read the geometry from a file so the best is to modify the
> geometry file. How do you generate the geometry?
> For example, if you use rtksimulated geometry, let's say that you were
> using:
> rtksimulatedgeometry -n 200 -a 200 -o g.xml
> then you'll have to replace it with
> rtksimulatedgeometry -n 202 -a 202 -o g.xml -f -1
> Don't forget to add dummy projection at the beginning and the end. If you
> use a more complex geometry, maybe SimpleRTK
> <http://wiki.openrtk.org/index.php?title=SimpleRTK> can be helpful (I'd
> use that) or you'd have to modify the cxx code to add these additional
> projections in the geometry and the projection stack.
> Simon
>
>
> On Tue, Dec 8, 2015 at 8:51 AM, Shiras Abdurahman <shiraska at gmail.com>
> wrote:
>
>> Dear Simon,
>>
>> Thanks a lot for the reply. Can you please inform me how can I set where
>> the arc starts?
>> Do I need to modify geometry also?
>> If you can point the line of code rtkfdk.cxx, it will be really helpful.
>>
>> With regards,
>> Shiras
>>
>> On Tue, Dec 8, 2015 at 7:56 AM, Simon Rit <simon.rit at creatis.insa-lyon.fr
>> > wrote:
>>
>>> Dear Shiras,
>>> Yes, for practical reasons the first and the last projections are set to
>>> 0 and the arc used in the Parker weighting starts between the first two
>>> projections and ends between the lasts two projections. There is a simple
>>> solution: add a projection at the beginning and the end of the arc, which
>>> can contain any pixel values but should be set where you want this arc to
>>> start. In the future, I think someone should once take the time to correct
>>> this but I haven't so far. I'll keep you posted on the mailing list when
>>> it's corrected.
>>> Simon
>>>
>>> On 07/12/2015 12:04, Shiras Abdurahman wrote:
>>>
>>> Hi all,
>>>
>>> I am trying to reconstruct a volume from projection data generated with
>>> C-arm CT. There are 248 projections with an angular range of 199 degree.
>>> Technically, parker weighting should run without any problems. However, I
>>> am getting an output message that "You do not have enough data for proper
>>> parker weighting". After parker weighting, the two extreme projections
>>> (projection number 1 and 248) were completely zero and thus reconstructed
>>> volume contained artifacts. When I increased the angular range, this
>>> problem did not happen. How can I solve this problem without increasing
>>> angular range? Is there any threshold constant that I can change in command
>>> line  or in my code?
>>>
>>> I really appreciate any help you can provide.
>>>
>>> With regards,
>>> Shiras
>>>
>>>
>>> _______________________________________________
>>> Rtk-users mailing listRtk-users at public.kitware.comhttp://public.kitware.com/mailman/listinfo/rtk-users
>>>
>>>
>>>
>>
>
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