mainkiefertest.html

Delaunay三角形的网格剖分程序

<TITLE>COG 2.1: CT data</TITLE>

<h1>CT Data</h1>

 <P>Of course, this particular human being does not look very happy.
But at least it can be seen that it is a human face - a quite nice
result for one day of implementation of their CT data into COG at the
TU Munich:

<P><IMG SRC="kiefertest.gif">


<PRE>
#include "cog/coglib.hxx"
#include "cog/cogenvoxmap.hxx"
#include <stdio.h>
int main()
{
</PRE>

<h2> Grayscale table </h2>

 <p>Data from header file

<listing>
1.50
58 64
-1 -1
2.000000 2.000000 1.000000
13.000000 1.000000 0.000000
1094 3654 1127
288 576 440
1295 1411 1351
1339 2065 1455
(threshold values: skin - fat - tissue - bones)
</listing>

 <P>The range we have used for the actual picture was a false one,
from another picture, as we have observed too late:

<PRE>
  wzGrayScaleTable table;
  table.addRange(2,930, 1894);  
//  table.addRange(2,1339, 2065);  
  table.addRange(1,0,0xffff);
 
  FILE *fp = fopen("kiefer.dat", "rb");

  wzIndex xlen = 58;
  wzIndex ylen = 64;
  wzIndex zlen = 74;  // = sizeof(file.dat)/(2*xlen*ylen)=549376/(58*64*2)

  cogenVoxmap   map = new CogenVoxmap(xlen,ylen,zlen);

  map->setXRange(0.0,1.0);
  map->setYRange(0.0,1.0);
  map->setZRange(0.0,1.0);
</PRE>

<h2> Filling the pixmap with values </h2>

 <P>Then you have to fill the pixel array with the regions.  
We assume that you read the <i>grayvalue</i> for a given pixel 
defined by <i>ix,iy,iz</i> from a file, but here we use the sum
<i>ix+iy+iz</i> as a simple example:

<PRE>
  wzGrayValue g;
  int ix,iy,iz;
  for(iz=0;iz<map->lz();iz++){
    for(iy=0;iy<map->ly();iy++){
      for(ix=0;ix<map->lx();ix++){
	fread(&g, sizeof g, 1, fp);
	g = (g>>8)|((g&0xff)<<8);
        wzGrayValue grayvalue = g;  // or something else from file
	map->pixmap()(ix,iy,iz) = table(grayvalue);
	// printf("%d, -> %d \n",grayvalue,table(grayvalue));
      }
    }
  }
  fclose(fp);
</PRE>

<p>setBorder defines the part of the full geometry which is used for
grid generation.

<PRE>
    //map->setBorder(0.2,0.8, 0.1,0.7, 0.3,0.9);
    map->setBorder(0.0,1.0, 0.0,1.0, 0.0,1.0);
  map->refinementGlobal(0.1,0.2,0.2); 
  map->faceRefinementGlobal(0.05,0.2);
  wzgrid grid = (*map->generator())();
  grid->write("test.sg");  
}
</PRE>