snark14.s170426 - A PICTURE RECONSTRUCTION PROGRAM


     <*>  EXAMPLE 3

     <*>  CREATION OF HEAD PHANTOM. GENERATION OF POLYCHROMATIC 

     <*>  PROJECTION DATA.

     <*> 

     <*>  CREATE A PHANTOM

     <*>  GENERATE PROJECTION DATA

     <#> CREATE                                                                                                                                                                                                                                                           

         EXAMPLE 3 HEAD PHANTOM


     <#> SPECTRUM POLYCHROMATIC 5

         energy spectrum is polychromatic with   5     energy levels
         with the following photon distribution
         energy level   percent
               40          10
               50          30
               60          30
               80          20
              100          10

     <#> OBJECTS
         description of objects
                                                                density at levels
 numb type  x-coord  y-coord x-length y-length    angle  av dens        40        50        60        80       100


    1 segm   1.3750  -7.5000   1.1000   0.6250  19.2000  -0.3275   -0.7340   -0.4720   -0.2880   -0.1160   -0.0290


    2 segm   1.3750  -7.5000   1.1000   4.3200  19.2100   0.3275    0.7340    0.4720    0.2880    0.1160    0.0290


    3 elip   0.0000   0.0000   8.6250   6.4687  90.0000   0.5400    1.0000    0.7000    0.5000    0.3000    0.2000


    4 elip   0.0000   0.0000   7.8750   5.7187  90.0000  -0.3300   -0.7370   -0.4750   -0.2910   -0.1180   -0.0290


    5 elip   0.0000   1.5000   0.3750   0.3000  90.0000  -0.0029   -0.0030   -0.0060   -0.0020   -0.0010   -0.0000


    6 segm   0.0000  -2.2500   1.1250   0.3750   0.0000  -0.0029   -0.0030   -0.0060   -0.0020   -0.0010   -0.0000


    7 segm  -1.0000   3.7500   1.0000   0.5000 135.0000  -0.0029   -0.0030   -0.0060   -0.0020   -0.0010    0.0000


    8 segm   1.0000   3.7500   1.0000   0.5000 225.0000  -0.0029   -0.0030   -0.0060   -0.0020   -0.0010    0.0000


    9 elip   0.6750  -0.7500   0.2250   0.1500 140.0000   0.0127    0.0250    0.0160    0.0100    0.0080    0.0080


   10 elip   0.7500   1.5000   0.3750   0.2250  50.0000   0.0046    0.0050    0.0040    0.0040    0.0060    0.0050


   11 tria   5.0250   3.7500   1.1250   0.5000 110.7500   0.3300    0.7370    0.4750    0.2910    0.1180    0.0290


   12 tria  -5.0250   3.7500   1.1250   0.5000 -110.7500   0.3300    0.7370    0.4750    0.2910    0.1180    0.0290

         scale factor multiplying object densities     1.0000

         seed set to 0
         inhomogeneity set to     0.0000

     <#> PHANTOM AVERAGE 1

         this run will generate a phantom
         density in each pixel is obtained as the average of 1 x 1 points


     <#> 23 0.77
         picture size 23 x 23,  pixel size     0.7700


     <#> RAYSUM AVERAGE 3

         this run will generate projection data
         projection data are calculated by dividing each ray interval into 3 substrips

         with aperture (substrip) weights     1     1     1


     <#> GEOMETRY


     <#> DIVERGENT ARC 78.0 110.0
         rays are divergent from point sources
         source to origin distance     78.0000
         the detectors lie on an arc with source to detector distance =   110.0000


     <#> RAYS USER 159 0.213
         number of rays per projection   159
         at detector spacing     0.2130


     <#> ANGLE 1
         total number of projections     1

         projection angles    0.0000


     <#> MEASUREMENT NOISY
         noise characteristics of projection data follow
               nature          characteristics

     <#> QUANTUM 10000000.0 360.0 CALIBRATION 2
               quantum        mean number of photons in actual measurement   1.0000e+07
                              mean number of photons in calibration measurement is   360.0000    times above
                              calibration is constant over all projections for any single ray
                              mean numbers of photons entering each substrip are
                                3.3333e+06   3.3333e+06   3.3333e+06 

     <#> SCATTER 0.24 0.4445
               scatter        the fraction scattered in line is     0.2400
                              scatter extends to a distance of     0.4445
                              dying linearly from the middle

     <#> SEED 1
          seed for random number generator is              1


     <#> BACKGROUND 0.0 0.0 0.0 0.0 0.0
                               at levels
                                      40        50        60        80       100 
          background absorption   0.0000    0.0000    0.0000    0.0000    0.0000 
 

     <#> RUN 
              0.001 seconds phantom creation
              0.000 seconds projection data creation
              0.002 seconds used for processing command crea


     <#> END