> When doing a 12 parameter normalization, I get confused about the
> parameters.
>
> Clearly, the first 6 parameters are translations and rotations.
>
> The last 6 are variously referred to as "scaling" or "zooms" or
> "affine", depending on where you encounter them in the code or
> documentation.
>
> When a brain is linearly strectched to match a template, is that a zoom
> or scaling or affine process?
Zoom, scale and stretching all pretty much refer to the same thing. Parameters
7, 8 and 9 refer to zooms in the x, y and z directions respectively:
____ __________
| | -> | |
| | | |
---- ----------
____
____ | |
| | -> | |
| | | |
---- ----
The affine part is sometimes referred to as shearing, and looks something like:
____ _____
| | -> / /
| | / /
---- ----
Regards.
-John
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