Biomedical Engineering Reference
In-Depth Information
Table 7.2: Statistics for isosurface generation on the kidney data set. This
table reports the number of meta-cells (no. of MC), number of active
meta-cells (activeMC), interval tree (IT) information, and total time for
isosurface generation (IsoTime). The data cache size used is 15 MB
No. of MC
7600
1000
288
125
ActiveMC
1140
474
256
125
IT size (kB)
938
.
95
203
.
56
61
.
23
21
.
25
IT time (sec)
1
1
1
1
IsoTime (sec)
13
15
15
20
algorithm. Also, the meta-cell technique minimizes the effect of the I/O bottle-
neck by reading from disk only those portions of the data necessary for step (1).
Besides, the time for an interval tree query was approximately 1 sec (“IT time” in
Table 7.2). As a consequence, if compared with the traditional implementation,
we observe a performance improvement of 2 sec when using 7600 meta-cells.
The final step, the T-surfaces evolution, is globally reported in Table 7.3 for
the kidney data set, maintaining the same partitions of Table 7.2. The quantity
“no. of I/O” reported in this table counts the number of times that the algorithm
reads a meta-cell from disk.
Again, the smaller the meta-cell size, the faster the whole process. Despite
the high number of I/O operations reported in row 2 of Table 7.3, we must
highlight that the total time for T-surfaces evolution without using the meta-cell
was 623 sec, against 600 sec for the worst case reported in Table 7.3. For the best
case, we observe a performance improvement of 120 sec, which is an important
result. The final surface (Fig. 7.16(c)) has 34 624 triangular elements.
Table 7.3: T-surfaces in the kidney data set. This table reports the
number of meta-cells (no. of MC), of number I/O operations (no. of
I/O), number of meta-cells that have been cut (CutMC), and the
total clock time for evolution (time). The data cache size is 15 MB
and the number of interactions is 16
No. of MC
7600
1000
288
125
No. of I/O
1244
4780
1818
1458
CutMC
1074
325
125
70
Time (sec)
503
570
584
600
