The code is indeed cryptic, here is an explanation: - if the pixel intensity is 0, then it's set to log(65536)-log(65535) https://github.com/SimonRit/RTK/blob/master/include/rtkElektaSynergyLookupTableImageFilter.hxx#L44 This value is set when the detector saturates - if it's different from 0 and 65535, then it's set to log(65536)-log(65536-pixelValue) https://github.com/SimonRit/RTK/blob/master/include/rtkElektaSynergyLookupTableImageFilter.hxx#L50 - if the pixel value is 65535, it is set to log(65536)-log(65535) (as pixel values 0 and 1) https://github.com/SimonRit/RTK/blob/master/include/rtkElektaSynergyLookupTableImageFilter.hxx#L56 This code is inspired by what (I think) Elekta XVI does with the raw data. Simon
On Thu, Dec 2, 2021 at 1:02 PM 雅之 服部 <masayuki.h.0...@gmail.com> wrote: > Thank you for your reply. > > I checked RTK 3D circular projection geometry doc and understood. > > I have another question. > After setting the geometry from the DBF file and reading the raw > projection data from .his file, > How do you convert the pixel values of the projection data to values for > reconstruction? > The pixel values in the .his file appear to have 16-bit values. > Is the value of the raw data the numerator as it is, and the maximum value > in the image as the denominator and the negative logarithm? > > Or is the value of raw data (probably a logarithmic system) once made into > a linear system using the unique conversion table of the elekta system? > I checked rtkElektaSynergyRawLookupTableImageFilter.h and > ElektaSynergyLookupTableImageFilter.h , > but I couldn't understand the difference between each source code because > I didn't study C ++ yet. > > Best regards. > > masa > > 2021年12月1日(水) 0:21 Simon Rit <simon....@creatis.insa-lyon.fr>: > >> Hi, >> Yes, this mailing list is meant for this kind of questions. >> Only this information is used, see here >> <https://github.com/SimonRit/RTK/blob/master/src/rtkElektaSynergyGeometryReader.cxx#L72-L74> >> . >> To understand the meaning, you can check that it's used here >> <https://github.com/SimonRit/RTK/blob/master/src/rtkElektaSynergyGeometryReader.cxx#L92>. >> Yes, it corresponds to DetectorOffsetX and DetectorOffsetY in the figure of >> this documentation <http://www.openrtk.org/Doxygen/DocGeo3D.html> for >> each projection. >> Simon >> >> On Tue, Nov 30, 2021 at 2:28 PM 雅之 服部 <masayuki.h.0...@gmail.com> wrote: >> >>> Dear rtk-users, >>> >>> I'm masa@japan. >>> >>> Is it okay to email General Technical Questions about RTK here? >>> >>> I'm working on RTK elekta reconstruction, but I'm new to C ++, so I >>> don't understand the specifics. >>> I downloadedIMAGE.DBF, FRAME.DBF and looked at the contents. >>> I understand that I am using angle information. But I didn't know what >>> U_CENTER and V_CENTER meant. >>> >>> Are they the offset numbers for each angle of the detector? >>> Also, which information is used for reconstruction from those two files? >>> >>> Thank you very much in advance. >>> >>> masa@japan >>> _______________________________________________ >>> Rtk-users mailing list >>> Rtk-users@public.kitware.com >>> https://public.kitware.com/mailman/listinfo/rtk-users >>> >>
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