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<DIV><FONT face=Arial size=2>Hi lisa,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Thank you for your kind information. But I am still
not get it. Would you mind to inform me more detail how to implement a ray
cast function that models x-ray attenuation (absorption and scattering) as you
suggested?</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I also tried to make a copy of
vtkVolumeRayCastMIPFunction (.h and .cxx), name it into
vtkVolumeRayCastXRayFunction and modify the code inside which calculate the
maksimum into calculate the average value. It works but the "X-Ray" image
is too soft (blurred). So, maybe your suggestion (x-ray attenuation) will give a
better result.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Last, if you don't mind, would you inform
me the way how I can save the projection (at 6 planes of the cube) of
the result into image files?</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Regards</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV>----- Original Message ----- </DIV>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=lisa.avila@kitware.com href="mailto:lisa.avila@kitware.com">Lisa
Avila</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=paulusjoo@hotmail.com
href="mailto:paulusjoo@hotmail.com">paulus joo</A> ; <A title=vtkusers@vtk.org
href="mailto:vtkusers@vtk.org">vtkusers@vtk.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Sunday, June 27, 2004 8:46 PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [vtkusers] How to generate
X-Ray Projection</DIV>
<DIV><BR></DIV>Hello,<BR><BR><BR>
<BLOCKQUOTE class=cite cite="" type="cite"><FONT face=arial size=2>1. I want
to generate X-Ray 2D image from the 3D volume. Some articles on the internet
mention that MIP projection can produce image look likes X-Ray image, and
some articles mention about "average intensity projection" should be used to
obtain X-Ray image. Which one (or both) was wrong?</BLOCKQUOTE><BR>A MIP
projection is a "maximum intensity projection" - the maximum value encountered
along the ray (either raw scalar or opacity mapping) is used for resulting
pixel value in the image. Therefore it is not like an x-ray in which (usually)
the whole volume contributes to the final image. Average would be closer to an
x-ray but remember this is just a rough approximation. You could also write a
ray cast function that models x-ray attenuation (absorption and scattering)
but keep in mind that the ray cast mapper only cast primary rays so you
couldn't account for any second-order scattering
effecfts.<BR><BR>Lisa<BR></FONT>
<P>
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