Table 1.
Comparison of computation costs for different reconstruction methods when a single image reconstruction is performed.
|
< 10% |
< 5% |
< 1% |
|||||
|---|---|---|---|---|---|---|---|
| F/B projection approach | Algorithm | Iteration cost (# iters) | Total recon. time | Iteration cost (# iters) | Total recon. time | Iteration cost (# iters) | Total recon. time |
| Direct calculation approach with precomputed system matrix (precomput. time: 12 708 s) | GPM-U | 359 s (216) | 13068 s | 599 s (378) | 13307 s | 1444 s (879) | 14152 s |
| GPM-N | 53 s (32) | 12761 s | 77 s (46) | 12786 s | 129 s (79) | 12838 s | |
| GPM-EN | 54 s (29) | 12762 s | 71 s (42) | 12780 s | 121 s (73) | 12830 s | |
| CG | 563 s (216) | 13272 s | 941 s (378) | 13650 s | 2376 s (878) | 15084 s | |
| PCG-N | 58 s (35) | 12766 s | 88 s (52) | 12796 s | 157 s (93) | 12865 s | |
| PCG-EN | 59 s (33) | 12767 s | 81 s (48) | 12789 s | 146s (86) | 12854 s | |
| PCG-EM | 81 s (45) | 12789 s | 111 s (66) | 12819 s | 268 s (151) | 12976 s | |
| CD | 37 s (20) | 12746 s | 46 s (26) | 12754 s | 64 s (38) | 12773 s | |
| OS-SPS-2 | 48 s (36) | 12756 s | 80 s (61) | 12788 s | 178 s (136) | 12887 s | |
| OS-SPS-5 | 20 s (15) | 12729 s | 35 s (26) | 12743 s | – | – | |
| OS-SPS-10 | 11 s (8) | 12719 s | 20 s (15) | 12728 s | |||
| On-the-fly approach (precomput. time: 110 s) | GPM-U | 4877 s (216) | 4987 s | 8523 s (378) | 8633 s | 16152 s (879) | 16262 s |
| GPM-EN | 688 s (29) | 798 s | 981 s (42) | 1091 s | 1614 s (73) | 1724 s | |
| CG | 6531 s (216) | 6641 s | 11400 s (378) | 11509 s | 21557 s (878) | 21666s | |
| PCG-EN | 735 s (33) | 845 s | 1035 s (48) | 1145 s | 1797 s (86) | 1907 s | |
| PCG-EM | 1033 s (45) | 1143 s | 1480 s (66) | 1590 s | 3291 s (151) | 3401 s | |