TABLE IV.
Computational costs (in seconds) of various components on multiple GPUs. The image volume is 512 × 512 × 64 with (a) 984, (b) 1968 and (c) 3936 views of size 888 × 64 in HD geometry.
| (A) 984 Views | ||||
|---|---|---|---|---|
| Number of GPUs | 1 | 2 | 3 | 4 |
| Projection | 1.478 | 1.107 | 1.102 | 1.101 |
| Projection Kernel | 1.009 | 0.703 | 0.579 | 0.457 |
| Integral image set (P) | 0.016 | 0.012 | 0.010 | 0.010 |
| Backprojection | 1.041 | 0.953 | 0.944 | 0.886 |
| Backprojection Kernel | 0.618 | 0.454 | 0.346 | 0.272 |
| Integral image set (BP) | 0.029 | 0.026 | 0.026 | 0.024 |
|
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| (B) 1968 Views | ||||
|
| ||||
| Number of GPUs | 1 | 2 | 3 | 4 |
| Projection | 2.550 | 2.045 | 1.762 | 1.581 |
| Projection Kernel | 2.012 | 1.411 | 1.184 | 0.897 |
| Integral image set (P) | 0.033 | 0.028 | 0.025 | 0.021 |
| Backprojection | 1.933 | 1.504 | 1.351 | 1.261 |
| Backprojection Kernel | 1.260 | 0.832 | 0.703 | 0.552 |
| Integral image set (BP) | 0.059 | 0.054 | 0.053 | 0.048 |
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| (C) 3936 Views | ||||
|
| ||||
| Number of GPUs | 1 | 2 | 3 | 4 |
| Projection | 4.685 | 3.513 | 2.841 | 2.542 |
| Projection Kernel | 4.029 | 2.853 | 2.305 | 1.791 |
| Integral image set (P) | 0.069 | 0.058 | 0.055 | 0.052 |
| Backprojection | 3.579 | 2.754 | 2.253 | 1.842 |
| Backprojection Kernel | 2.693 | 1.746 | 1.461 | 1.174 |
| Integral image set (BP) | 0.125 | 0.120 | 0.117 | 0.113 |