[Rtk-users] Parker weighting

[Shiras Abdurahman]

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
>
>
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>
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