[Rtk-users] The preprocessing for .bmp and .tif images

[Guangming Zang]

Thanks Chao and Simon.
Yes, my .tif images are 16 bit depth( uint16 ) , i think it is the same
with unsigned short.
Another question related to  geometry is that, several months ago, i asked
the tif file geometey settings, and Chao replied and kindly pointed that
<http://webcache.googleusercontent.com/search?q=cache:1KHuL-ayALwJ:public.kitware.com/pipermail/rtk-users/2014-November/000621.html+&cd=1&hl=en&ct=clnk&gl=sa>
i should be careful about image's dpi
But, i still can not understand why it is related to image's dpi.
 For example, my tif images' information and some geometry information from
scanner are like this:
* 1916*1536 dimensions *
*  pixelsize 0.127*
*  SDD  983*
*  SID    413*
The interesting part is that, when using  rtksimulatedgeometry  command ,  i
set all parameters identical to physical distance (mm). it does not show
anything, not matter care about dpi or not(suppose   rtkfdk command after
that  is correct). i.e.,
1. rtksimulatedgeometry -n 360 -o geometry.xml   --sdd="983"
--sid="413"    --proj_iso_x="-121.666" --proj_iso_y="-97.536"

or change the sid to 2/3 *sid because of  300 dpi instead of 200 dpi
2. rtksimulatedgeometry -n 360 -o geometry.xml   --sdd="655.3333"
--sid="413"    --proj_iso_x="-121.666" --proj_iso_y="-97.536"


But when i set the *sdd *divide by pixelsize(0.127),  and other parameters
like this, it reconstructed a  volume seems correct(at least show the whole
object)

3. rtksimulatedgeometry -n 360 -o geometry.xml   --sdd="7740.15748"
--sid="413.423889"    --proj_iso_x="-958" -proj_iso_y="-768"

so would you please help me to find what happened??

Sorry , again for this long letter. :(

Thanks very much.

With my Regards
Guangming





*Guangming Zang (Alex)*
*King Abdullah University of Science and Technology(KAUST)*
*University of Chinese Academy of Sciences(UCAS)*




2015-06-16 17:43 GMT+03:00 Simon Rit <simon.rit at creatis.insa-lyon.fr>:

> Hi,
> This is correct if your tif is of type "unsigned short".
> Simon
>
> On Tue, Jun 16, 2015 at 4:41 PM, Chao Wu <wuchao04 at gmail.com> wrote:
> > Look at http://www.openrtk.org/Doxygen/dot_inline_dotgraph_16.png
> > For tif and bmp I think they go through the left most path (except for
> the
> > Elekta branch).
> >
> >
> > 2015-06-16 15:47 GMT+02:00 Guangming Zang <guangming.zang at kaust.edu.sa>:
> >>
> >> Hi RTK community,
> >> Sorry to bother you again,  but i was wondering for the projections in
> the
> >> format of .bmp and .tif files. (e.g., say the bmp images  range from
> >> [0,255], tif images range from [1,521]) . what are the next steps and
> >> preprocessing pipelines in RTK for bmp and tif ?? I look into the
> >> rtkProjectionsReader.txx, however, for me, i think it does not explain
> >> clearly.
> >> So anyone can help me?
> >>
> >> with my Regards
> >> Guangming
> >>
> >> Guangming Zang (Alex)
> >> King Abdullah University of Science and Technology(KAUST)
> >> University of Chinese Academy of Sciences(UCAS)
> >>
> >>
> >>
> >>
> >> ________________________________
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> >
> >
>

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