Image Shifts
The cross-sectional image slices in the Visible Human Dataset do not align perfectly as observed in [12]. At some of the image slices, the picture is significantly shifted compared to the one above it and thus all the slices below that are misaligned by that shift (Fig. 4). To counter the misalignment, the slices where these shifts occur are identified, the amount of the shift is determined, and the slices are shifted back. The shifts were quantized in terms of pixels and their values were determined by maximizing the overlap between the mask of the slices under operation and the slices above them (e.g., mask of slice 1231 was compared to that of slice 1230). The shifts were then confirmed by visual inspection. Table 1 shows the pixel shifts made to the slices while developing the AustinWoman model.
Figure 4: A cropped portion (at the same position of each slice) of the
AustinMan model's spinal cord from slices a_vm1230.png (top) and a_vm1231.png (bottom)
indicating the relative shift of 9 pixels to the right.
Table 1a: Pixel Shifts Used to Align the Dataset (AustinWoman v2.0 and older)
| Relative Pixel Shift to the Right (in the x-direction) Compared to Previous Image | Cumulative Pixel Shifts to the Right (in the x-direction) |
| Slice 1495: -4 | Slices 1495-1976: -4 |
| Slice 1977: -4 | Slices 1977-2730: -8 |
Table 1b: Pixel Shifts Used to Align the Dataset (AustinWoman v2.1 and newer)
| Relative Pixel Shift to the Right (in the x-direction) Compared to Previous Image | Cumulative Pixel Shifts to the Right (in the x-direction) |
| Slice 1495: -4 | Slices 1495-1976: -4 |
| Slice 1977: -4 | Slices 1977-2730: -8 |
| Slice 2331: Rotation, see note below | Slice 2331-2730: Rotation, see note below |
Note: For AustinWoman v2.1 and newer, the shifts in Table 1b are first performed. Then, starting at slice 2331 and going down to the bottom (2730), there is a rotation of 1.698 degrees counterclockwise about the pixel located at (847,317).
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