[Rtk-users] problem while determining the interpolation weights in 4D ROOSTER Reconstruction

[Cyril Mory]

Hi again Ruoyan,


I have investigated further and found the source of the problem: the 
code performs a rounding of the phase signal to two digits, which for 
some values of your phase ended up to be 1. And the rest of the code 
assumes that the phase belongs to [0; 1[, i.e. there should never be a 
value 1.
The rounding is useful for optimization: projections with identical 
phases can be forward and backprojected together, which is faster than 
one-by-one, and with high-precision phase values, there are never two 
equal phase values.


So I just fixed the bug by setting the phase to 0 when its rounding is 
equal to 1, which should do the trick. The pull request is being tested, 
it should be merged soon.


Thanks for reporting your issue.

Regards,

Cyril


On 09/01/2018 11:31, Cyril Mory wrote:
>
> Hi Ruoyan,
>
>
> I've had a look at your file sphase.txt, it looks perfectly fine to 
> me. The problem must lie elsewhere. Does the application 4D ROOSTER 
> work with the example data provided on the wiki ? If it does, then the 
> problem lies in your data. In that case, please run
>
>
> rtkprojections --path D:\bd\20171116 --regexp .*.his -o projections.mhd
>
>
> and send us the "projections.mhd" file. It will contain only the 
> metadata of your projections, and we'll be able to run the same 
> command line as you and try to reproduce the problem.
>
>
> If, on the other hand, it doesn't even work with the example data 
> provided on the wiki, it is a software problem. In that case, can you 
> first update to the latest RTK (the git master branch), recompile and 
> test again ?
>
>
> Best regards,
>
> Cyril
>
>
> On 26/12/2017 10:47, ry.meng wrote:
>> Hi
>>
>> Thank you for your reply. I have checked the value in sphase.txt and 
>> don't have any value larger or equal to 5. Maybe the problem lies 
>> elsewhere? Thanks.
>>
>> Regards
>>
>> Ruoyan Meng
>>
>> On 12/26/2017 17:14，Simon Rit<simon.rit at creatis.insa-lyon.fr> 
>> <mailto:simon.rit at creatis.insa-lyon.fr> wrote：
>>
>>     Hi,
>>     If you look at the code
>>     <https://github.com/SimonRit/RTK/blob/master/code/rtkPhasesToInterpolationWeights.hxx#L154>,
>>     you'll see that the error message corresponds to the case where
>>     you have a phase which equals the number of frames. This cannot
>>     be since it is 0-based. In other words, with the option "--frames
>>     5", you cannot have a value larger or equal to 5 in your file
>>     sphase.txt.
>>     Simon
>>
>>     On Mon, Dec 25, 2017 at 9:36 AM, ry.meng <ry.meng at siat.ac.cn
>>     <mailto:ry.meng at siat.ac.cn>> wrote:
>>
>>
>>         Hi:
>>         When I tried  the application of 4D ROOSTER Reconstruction
>>         with my own data, it will stop for the following reason:
>>         problem while determining the interpolation weights. Maybe
>>         you guys have met this problem before and have a solution for
>>         it. Thank you very much and I hope to receive your reply soon.
>>
>>
>>         Happy Holidays!
>>
>>
>>         Regards
>>
>>         Ruoyan Meng
>>
>>         ------------------------------------------------------------------------------------------
>>
>>         Research Center for Medical Robotics and Minimally Invasive
>>         Surgical Devices,
>>         Institute of Biomedical and Health Engineering,
>>         Shenzhen Institutes of Advanced Technology, Chinese Academy
>>         of Sciences
>>         Tel: +86-18576617767 <tel:+86%20185%207661%207767>
>>         Email: ry.meng at siat.ac.cn <mailto:qs.zhu at siat.ac.cn>
>>         Zip:       518055
>>         Add: No. 1068 Xueyuan Avenue, Nanshan, Shenzhen, China
>>         <https://maps.google.com/?q=No.+1068+Xueyuan+Avenue,+Nanshan,+Shenzhen,+China&entry=gmail&source=g>
>>
>>
>>
>>
>>
>>
>>
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