From: Dave Akers (dla@engr.sgi.com)
Date: 08/01/2000 17:10:28
Hi Vasu,
I think your problem is that your datasets are byte-swapped. At the
bottom of the webpage you referenced, there's a discussion of this. You'll
need to run the command
% dd if=3dhead of=3dhead.new conv=swab
This will byte-swap your unsigned short raw data. Next step is to convert
it to .tif:
% imgcopy "3dhead.new#raw%size=256,256,109%colormodel=luminance%type=ushort"
output_byteswapped.tif
Then you should be able to visualize it appropriately with voglBasic. The
3-D head dataset happens to have most of its values concentrated between
around 0 and 2000, so you might want to try:
% voglBasic output_byteswapped.tif -dataRange 0 2000
Let me know if you still have problems. :)
Dave
On Tue, 1 Aug 2000, Vasudevan Ramanujam wrote:
> Hi Dave
>
> I would appreciate if you could tell me the exact
> procedure for viewing the data set given in the
> following location,since my data set too is similar to
> the ones that are provided here:
>
> http://asec.cs.gsu.edu/asecdl/materials/vol-viz/volume_visualization_data_sets.htm
>
> This is what I did with the Head data set:
> 1.imgcopy
> "head#raw%size=w,h,z%colormodel=luminance%type=ushort"
> output.tif .here it is a 256*256*109 data set
> 2.voglBasic output.tif
>
> All i get is a hazy picture or no picture.
>
> 3.Now if I do imgcopy -tchar then the output tif image
> becomes half the original size approximately.Infact
> during conversion it gives a warning "data bounds out
> of range".Neverthless,voglBasic gives a
> "comparatively" better output,but not the best
> output,since it reads only half the dataset(8 bits
> instead of 16 bits).The idea to convert the datatype
> to "char" came to me,since all the example Tif files
> are in that format.
>
> Any help will be greatly appreciated!
> Thx
> Vasu
>
>
>
>
> --- Dave Akers <dla@lobster.engr.sgi.com> wrote:
> > Gareth and Vasu,
> >
> > I've tested Volumizer with unsigned short format
> > and I'm finding no
> > problems at all. Both imgcopy and voglBasic seem to
> > do the right thing for
> > my test cases. Can you send me (to dla@sgi.com) an
> > example case that
> > doesn't work? What specifically do the results look
> > like?
> >
> > Not sure about the imgcopy problems with float
> > format, but I'll look
> > into it.
> >
> > Dave
> >
> > On Tue, 1 Aug 2000, Gareth Morgan wrote:
> >
> > > Good news:
> > > Experimenting myself just now I have got voglBasic
> > to work with float data
> > > type. Though, as you say,
> > > it appears not to work with ushort.
> > >
> > > Bad news:
> > > imgcopy doesn't seem to produce sensible output
> > when converting to float
> > > (even if you use -m0.0 & -M1.0 flags to set
> > min/max values), and produces a
> > > garbled version of the image.
> > > You may have to write your own conversion program
> > to do this.
> > >
> > > -----Original Message-----
> > > From: Vasudevan Ramanujam
> > [mailto:devvas@yahoo.com]
> > > Sent: 01 August 2000 14:58
> > > To: Gareth Morgan
> > > Cc: info-volumizer@corp.sgi.com
> > > Subject: RE: My Volumetric data
> > >
> > >
> > > Hi
> > > I am running my applications on SGI Onyx2 with 64
> > MB
> > > texture memory.
> > > I was able to view my data after converting the
> > data
> > > type from "ushort" to "char",but the problem is
> > that
> > > it comes at the expense of volumetric detail.The
> > data
> > > now is just half the original size.
> > > I tried converting the output data type to "long"
> > > ,but the Volumizer says it is an unknown data
> > > format.Does Volumizer example applications accept
> > only
> > > "char" data type?
> > > Please let me know the other data types supported.
> > > Thanks
> > > Vasu
> > >
> > >
> > >
> > >
> > >
> > > > Hi all
> > > >
> > > > Can anybody please help me with my problem?Here
> > it
> > > > is:
> > > >
> > > > My Volumetric data(female body anatomy) is
> > > > Unsigned
> > > > short and it is 128*128*1024*2 bytes =33554432
> > big.I
> > > > converted it into a Tif file so that Volumizer
> > can
> > > > accept it,but it is not working.So,i have made a
> > > > smaller version of the data set, which is
> > > > 64*64*256*2=2097152 bytes long.But still the
> > > > Volumizer
> > > > example application does not accept it.HOw do i
> > code
> > > > around it so that i will be able to visualize my
> > > > data
> > > > set.Any help in this regard is appreciated.
> > > > Thx in advance
> > > > Vasu
> > > >
> > > >
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