| CT LUNG VISUALISATION [message #11541] |
Tue, 21 April 1998 00:00  |
Fraser Hatfield
Messages: 2
Registered: April 1998
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Junior Member |
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I was wondering if someone advise me on the following.
I am trying to create a 3-D visualisation of the lungs from CT data
within IDL. To do this I use the Shade_volume and polyshade commands.
The problem I have is that the voxels are anisotropic, and so
the visualisation looks squashed on storing the slices in an array
of size (512,512,26)
The dimensions are as follows.
x=512,y=512,z=26, xres = 0.5mm, yres=0.5mm, zres=10mm.
(NB the ct slices are contiguous)
Could someone suggest the best way to manipulate the data so
that the visualisation has the correct proportions in all directions
Cheers
Fraser
Dr Fraser Niles Hatfield
Centre for Industrial and Medical Informatics (CIMI)
University of Nottingham
E-mail:fnh@cs.nott.ac.uk ; http://www.cimi.nottingham.ac.uk
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| Re: CT LUNG VISUALISATION [message #11606 is a reply to message #11541] |
Mon, 27 April 1998 00:00  |
Martin Schultz
Messages: 515
Registered: August 1997
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Senior Member |
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Fraser Hatfield wrote:
>
> I was wondering if someone advise me on the following.
> I am trying to create a 3-D visualisation of the lungs from CT data
> within IDL. To do this I use the Shade_volume and polyshade commands.
> The problem I have is that the voxels are anisotropic, and so
> the visualisation looks squashed on storing the slices in an array
> of size (512,512,26)
> The dimensions are as follows.
> x=512,y=512,z=26, xres = 0.5mm, yres=0.5mm, zres=10mm.
> (NB the ct slices are contiguous)
> Could someone suggest the best way to manipulate the data so
> that the visualisation has the correct proportions in all directions
>
Although I have never seen my loungs in IDL, you may want to try congrid
in order to interpolate your data in the z dimension:
newdata = congrid(data,512,512,520,/interpolate)
Hope this helps,
Martin.
------------------------------------------------------------ -------
Dr. Martin Schultz
Department for Earth&Planetary Sciences, Harvard University
186 Pierce Hall, 29 Oxford St., Cambridge, MA-02138, USA
phone: (617)-496-8318
fax : (617)-495-4551
e-mail: mgs@io.harvard.edu
IDL-homepage: http://www-as.harvard.edu/people/staff/mgs/idl/
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| Re: CT LUNG VISUALISATION [message #11727 is a reply to message #11541] |
Thu, 30 April 1998 00:00 |
David Foster
Messages: 341
Registered: January 1996
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Senior Member |
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Martin Schultz wrote:
>
> Fraser Hatfield wrote:
>>
>> I was wondering if someone advise me on the following.
>> I am trying to create a 3-D visualisation of the lungs from CT data
>> within IDL. To do this I use the Shade_volume and polyshade commands.
>> The problem I have is that the voxels are anisotropic, and so
>> the visualisation looks squashed on storing the slices in an array
>> of size (512,512,26)
>> The dimensions are as follows.
>> x=512,y=512,z=26, xres = 0.5mm, yres=0.5mm, zres=10mm.
>> (NB the ct slices are contiguous)
>> Could someone suggest the best way to manipulate the data so
>> that the visualisation has the correct proportions in all directions
>>
>
> Although I have never seen my loungs in IDL, you may want to try congrid
> in order to interpolate your data in the z dimension:
>
> newdata = congrid(data,512,512,520,/interpolate)
>
Since CT data is usually 16-bit integer data, this would create a
270MB array! I think a better approach would be to use IDL's system
variables !X.S, !Y.S, !Z.S, and !P.T together with the /T3D keyword
in the POLYSHADE() call, together with the Z buffer.
Here is a code snippet from one of our programs. Email me if you
have questions.
!P.T = d.isosurf_pt
!X.S = d.isosurf_x_s
!Y.S = d.isosurf_y_s
!Z.S = d.isosurf_z_s
set_plot,'Z'
erase
b = polyshade(verts, polys, /t3d) ; This brain is upside down
Dave
--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~
David S. Foster Univ. of California, San Diego
Programmer/Analyst Brain Image Analysis Laboratory
foster@bial1.ucsd.edu Department of Psychiatry
(619) 622-5892 8950 Via La Jolla Drive, Suite 2240
La Jolla, CA 92037
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~
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