I'm sorry I don't have the time available to do background research
and walk you through all this stuff.
On Jan 15, 2008 7:23 AM, hesicong2006 <[EMAIL PROTECTED]> wrote:
>
> Hi, Robert,
> I find that when using lower fov of camera, the volume artifacts will goes
> alway. See my pictures and notice the yellow portion. I wonder if we can use
> ortho view inside of perspective view. In this way, it should fix the
> artifacts. I tried to change the camera setting, but it leaves me a blue
> screen, I don't know why. The last lines of osgVolume.cpp is:
> ...
> if (rootNode)
> {
>
> // set the scene to render
> viewer.setSceneData(rootNode);
>
> viewer.getCamera()->setProjectionMatrixAsOrtho(10,10,-10,10,0.1,1000);
> //One line I added
> // the the viewers main frame loop
> viewer.run();
> }
> Please help me or point out how I can do to use ortho view? Thanks!
>
>
>
> Robert Osfield wrote:
> Hi,
>
> I haven't looked at the data - I simply don't have the available time
> to go into this right now. I doubt its a bug, rather a limitation in
> the technique. Please understand the shader is a quick knock
> together. If it doesn't work perfectly in all situations than
> something I'm happy to except, it was never meant to be anything other
> than a basic example. There are large texts on the topic on volume
> rendering and lots of stuff online.
>
> If you can wait, there are plans for the development of an osgVolume
> NodeKit, that will be a full blown implementation of various published
> techniques as well as few that probably come up with ourselves once we
> start pushing the start of the art. This project should be under way
> by the summer.
>
> Robert.
>
> On Jan 11, 2008 3:20 AM, hesicong2006 <[EMAIL PROTECTED]> wrote:
>
>
> Thanks, and sorry for my poor English.....
> To let the things clear, please P1.jpg attached. I draw three yellow
> line to show the problem. Notice the red-yellow dot line, it starts from
> the intersection of two yellow lines and goes in direction of the line
> behind the head. You can the head becomes hollow when the line goes
> through. If you try my volumedata, it will show you much more clearer.
>
> Gerrick Bivins wrote:
>
>
> Hi,
> If you are referring to the "slices" that you see, this is a typical
> artifact in volume rendering applications due
> to under-sampling (low number of polygon slices). A simple solution
> (not efficient though) is to increase the number of slices
> until the artifact goes away (usually 2*max_texture_dimension).There
> are other solutions (more efficient)out there
> as well...(The Real-Time volume Graphics
> <http://www.real-time-volume-graphics.org/> book is a great
> reference).If you are not talking about the
> slicing, it's not very clear what you mean by "And notice the
> head,it's a little strange"
> biv
> On Jan 10, 2008 10:59 AM, hesicong2006 <[EMAIL PROTECTED]
>
>
> <mailto:[EMAIL PROTECTED]>> wrote:
>
> Thanks Robert and could you try my volume data? (Sorry its too big for
> email, but you can download from
> http://www.hesicong.net/volumedata.rar)
> You can see the animated failure.
> I recaptured the image, P1.jpg and P2.jpg use the default setting you
> provided. In P3, I decreased the sampleDensity, but it still have the
> problem.
> At last my computer is:
> CPU: Intel Core 2 Duo Q6600
> RAM: 3G
> GPU: Geforce 8800GTS 320M with 169.09 driver under XP. I think it will
> not be hardware failure or driver failure. Is that caused by
> projection
> view? I tried to modify it to ortho view, but I even can't see the
> volume cube~~~
>
> At last the command I use is here, thanks again for your help.
> osgvolumed --shader --replace-alpha-with-luminance --images 000.TIF
> 001.TIF 002.TIF 003.TIF 004.TIF 005.TIF 006.TIF 007.TIF 008.TIF
> 009.TIF
> 010.TIF 011.TIF 012.TIF 013.TIF 014.TIF 015.TIF 016.TIF 017.TIF
> 018.TIF
> 019.TIF 020.TIF 021.TIF 022.TIF 023.TIF 024.TIF 025.TIF 026.TIF
> 027.TIF
> 028.TIF 029.TIF 030.TIF 031.TIF 032.TIF 033.TIF 034.TIF 035.TIF
> 036.TIF
> 037.TIF 038.TIF 039.TIF 040.TIF 041.TIF 042.TIF 043.TIF 044.TIF
> 045.TIF
> 046.TIF 047.TIF 048.TIF 049.TIF 050.TIF 051.TIF 052.TIF 053.TIF
> 054.TIF
> 055.TIF 056.TIF 057.TIF 058.TIF 059.TIF 060.TIF 061.TIF 062.TIF
> 063.TIF
> 064.TIF 065.TIF 066.TIF 067.TIF 068.TIF 069.TIF 070.TIF 071.TIF
> 072.TIF
> 073.TIF 074.TIF 075.TIF 076.TIF 077.TIF 078.TIF 079.TIF 080.TIF
> 081.TIF
> 082.TIF 083.TIF 084.TIF 085.TIF 086.TIF 087.TIF 088.TIF 089.TIF
> 090.TIF
> 091.TIF 092.TIF 093.TIF 094.TIF 095.TIF 096.TIF 097.TIF 098.TIF
> 099.TIF
> 100.TIF 101.TIF 102.TIF 103.TIF 104.TIF 105.TIF 106.TIF 107.TIF
> 108.TIF
> 109.TIF 110.TIF 111.TIF 112.TIF 113.TIF 114.TIF 115.TIF 116.TIF
> 117.TIF
> 118.TIF 119.TIF 120.TIF 121.TIF 122.TIF 123.TIF 124.TIF 125.TIF
> 126.TIF
> 127.TIF 128.TIF 129.TIF 130.TIF 131.TIF 132.TIF 133.TIF 134.TIF
> 135.TIF
> 136.TIF 137.TIF 138.TIF 139.TIF 140.TIF 141.TIF 142.TIF 143.TIF
> 144.TIF
> 145.TIF 146.TIF 147.TIF 148.TIF 149.TIF 150.TIF 151.TIF 152.TIF
> 153.TIF
> 154.TIF 155.TIF 156.TIF 157.TIF 158.TIF 159.TIF 160.TIF 161.TIF
> 162.TIF
> 163.TIF 164.TIF 165.TIF 166.TIF 167.TIF 168.TIF 169.TIF 170.TIF
> 171.TIF
> 172.TIF 173.TIF 174.TIF 175.TIF 176.TIF 177.TIF 178.TIF 179.TIF
> 180.TIF
> 181.TIF 182.TIF 183.TIF 184.TIF 185.TIF 186.TIF 187.TIF 188.TIF
> 189.TIF
> 190.TIF 191.TIF 192.TIF 193.TIF 194.TIF 195.TIF 196.TIF 197.TIF
> 198.TIF
> 199.TIF 200.TIF 201.TIF 202.TIF 203.TIF 204.TIF 205.TIF 206.TIF
> 207.TIF
> 208.TIF 209.TIF 210.TIF 211.TIF 212.TIF 213.TIF 214.TIF 215.TIF
> 216.TIF
> 217.TIF 218.TIF 219.TIF 220.TIF 221.TIF 222.TIF 223.TIF 224.TIF
> 225.TIF
> 226.TIF 227.TIF 228.TIF 229.TIF 230.TIF 231.TIF 232.TIF 233.TIF
> 234.TIF
> 235.TIF 236.TIF 237.TIF 238.TIF 239.TIF 240.TIF 241.TIF 242.TIF
> 243.TIF
> 244.TIF 245.TIF 246.TIF 247.TIF 248.TIF 249.TIF 250.TIF 251.TIF
> 252.TIF
> 253.TIF 254.TIF 255.TIF
>
> Robert Osfield wrote:
> > Hi,
> >
> > I'm the author of the osgvolume example. Its just a quick
> > prototype/proof of concept, and one I haven't touched in the
> last year
> > or two so its a bit cold. The visual errors on the frame region
> > you've observed aren't ones I've seen before, but then I've never
> > played with a volume dataset that has a frame in it. I'm afraid I
> > can't think of any obvious failure modes that would introduce these
> > artefacts. Try different hardware/OpenGL drivers/OS to see if the
> > artefacts changes. As for the head region, I can't spot any
> problem.
> >
> > Robert.
> >
> > On Jan 10, 2008 6:40 AM, hesicong2006 <[EMAIL PROTECTED]
> <mailto:[EMAIL PROTECTED]>> wrote:
> >
> >> Hi everyone:
> >> I'm now doing a medical application using volume rendering
> technology.
> >> osgVolume example gives me a very good start, thanks to people who
> >> contributes to this example. But I found some image errors (see
> >> attachments) , In p1.jpg, see the red circle, the outboder line
> bends.
> >> In p2.jpg, the line bends more than that in p1.jpg. And notice
> the head,
> >> it's a little strange. I tried to fix this problem, but I still
> can't
> >> figure out why it happens to be like this.Does someone can help
> me or
> >> point out why it appears like this?
> >> Thanks very much!
> >>
> >> _______________________________________________
> >> osg-users mailing list
> >> [email protected]
> <mailto:[email protected]>
> >>
> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
> <http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org>
> >>
> >>
> >>
> >
> >
>
>
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