[Rtk-users] DCM projections

[Simon Rit]

Hi Safdari,
Please, the mailing list! And use an adequate email subject if possible.
We already process some DCM projections for the IBA scanner. The RTK
projections reader
<http://www.openrtk.org/Doxygen/classrtk_1_1ProjectionsReader.html>is not
the simplest but if you follow what happens to IBA projections in
rtkProjectionsReader.txx
<http://www.openrtk.org/Doxygen/rtkProjectionsReader_8txx_source.html>, it
will give you an hint on what is going on. By default, it will assume that
the input files are line integrals.
Simon

On Thu, Mar 5, 2015 at 3:19 PM, safdary mohsen <ieee.safdary at gmail.com>
wrote:
> Hello Simon
> How can i insert .dcm projections insted of .his or .hnd projections?
> Thank you.
>
> best regards,
> Safdari.M
>
> On Wed, Mar 4, 2015 at 8:39 PM, Simon Rit <simon.rit at creatis.insa-lyon.fr>
> wrote:
>>
>> Same remark as Cyril, the mailing list please.
>> I don't get what you say. If the focus is not moving in the coordinate
>> system of the room but the object is, then in the coordinate sytem of the
>> object, the focus moves. You must describe the geometry in the coordinate
>> system of the object, not in the coordinate system of the room.
>> Yes, iterative reconstruction sounds more suitable in such a case but you
>> still have to describe the geometry adequately.
>> Simon
>>
>> On Wed, Mar 4, 2015 at 5:03 PM, "Robert Calließ" <Robert.Calliess at gmx.de>
>> wrote:
>>>
>>> Hello Simon,
>>> the reason I moved the object is to get images from different viewing
>>> angles. So the
>>> focus is fixed, cant be moved. The object can be moved and the
detectors.
>>> So I get
>>> the 9 projection images including one image that is the orthogonal view.
>>> But isn't the
>>> S-ART a suitable algorithm for such a problem ? AS far as I know it is
>>> more flexible handling
>>> different viewing angles and few projection images than the FDK.
>>>
>>> Thank you.
>>>
>>> best regards,
>>> Robert.
>>>
>>> Gesendet: Mittwoch, 04. März 2015 um 13:59 Uhr
>>> Von: "Simon Rit" <simon.rit at creatis.insa-lyon.fr>
>>> An: "Robert Calließ" <Robert.Calliess at gmx.de>
>>> Cc: "rtk-users at openrtk.org" <rtk-users at openrtk.org>
>>> Betreff: Re: Re: [Rtk-users] sart for planar tomosynthesis
>>> Hi Robert,
>>> You're taking the problem from the wrong point of view. You should place
>>> the source and the detector in the coordinate system of the object, so
we
>>> should not see your object move in your diagram. Move the source and
>>> detector only.
>>> About the size, either the detector is too small or the object is too
>>> large but for sure, in practice and in RTK, both can't change during the
>>> acquisition!
>>> Good luck,
>>> Simon
>>>
>>> On Wed, Mar 4, 2015 at 1:55 PM, "Robert Calließ" <Robert.Calliess at gmx.de
>
>>> wrote:
>>>>
>>>>
>>>>
>>>> Hello Simon,
>>>> I try to handle a planar tomosynthesis where the flat panel detectors
>>>> are arranged in a 3x3 matrix. For each view,
>>>> the object and the detector are aligned, so that the "line" from xray
>>>> source through the object center and through the middle
>>>> of the detector. As you told me, I do not change the size of the
object.
>>>> The problem is, that the object in the orhogonal view (center)
>>>> covers the whole detector. For any other view some parts of the object
>>>> are outside of the cone beam and so are not part of the
>>>> projection image (see attached pdf). The detector's size is fixed and
>>>> the object's size as well.
>>>>
>>>> Best regards,
>>>> Robert
>>>>
>>>> Gesendet: Dienstag, 03. März 2015 um 16:37 Uhr
>>>> Von: "Simon Rit" <simon.rit at creatis.insa-lyon.fr>
>>>> An: "Robert Calließ" <Robert.Calliess at gmx.de>
>>>> Cc: "rtk-users at openrtk.org" <rtk-users at openrtk.org>
>>>> Betreff: Re: [Rtk-users] sart for planar tomosynthesis
>>>> Hi Robert,
>>>> I'm not sure I understand what your tomosynthesis does. But what I
would
>>>> do is fix all geometric parameters to constant values, including the
angles
>>>> (gantry, inplane, outofplane), except SourceOffsetX, SourceOffsetY,
>>>> ProjectionOffsetsX, ProjectionOffsetsY. In any case, I would not
modify the
>>>> object size and positions, this is a given in practice. If you want to
cover
>>>> your object, just use a larger detector.
>>>> Good luck,
>>>> Simon
>>>>
>>>> On Tue, Mar 3, 2015 at 3:56 PM, "Robert Calließ"
>>>> <Robert.Calliess at gmx.de> wrote:
>>>>>
>>>>> Hello,
>>>>> I know that RTK's primary use is the field of a circular trajectory.
>>>>> But if one would
>>>>> use the the RTK for tomosynthesis the first choice's algorithm would
be
>>>>> the
>>>>> S-ART.
>>>>>
>>>>> Following situation. The Focus is fixed. The object only moves in the
>>>>> xy plane and also the
>>>>> detectors, for instance flat panel detectors. So that a virtually line
>>>>> would always goes from
>>>>> the focus through the object center and ends in the detector's center.
>>>>> I wonder how to handle the different geometry settings for this kind
of
>>>>> reconstruction.
>>>>> What I mean is, that with a circular trajector the parameters FOD, FDD
>>>>> and ODD always
>>>>> remain the same because we are rotationg around an axis. But for the
>>>>> case of planar
>>>>> tomosynthesis the FOD, FDD will be different from the orthogonal view.
>>>>> Usually we calculate the physical size of the object based on the FOD
>>>>> and FDD to get sure
>>>>> that the object fits within the cone.
>>>>> But now for the case of a planar tomosynthesis do one need to
>>>>> recalculate the object size
>>>>> so that the object fits into the current cone beam or do one work with
>>>>> the object size calculated
>>>>> for the center view (orthogonal view, where the original FOD, FDD are
>>>>> given) ?
>>>>>
>>>>> I think if I would resize the object for every viewing position this
>>>>> would change a lot for the
>>>>> reconstruction result as I also change the "ray paths".
>>>>>
>>>>> Does anyone has experiences with this kind of reconstruction ?
>>>>>
>>>>>
>>>>> best regards,
>>>>> Robert C.
>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Rtk-users mailing list
>>>>> Rtk-users at public.kitware.com
>>>>> http://public.kitware.com/mailman/listinfo/rtk-users
>>>>>
>>
>>
>>
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>
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