Once an image has a .mat file, then SPM99 ignores the origin and
voxel size information in the headers. The best way of changing the
origin is via the Display button. It also allows you to re-orient
your images any way you like. The main problem with the origin field
in the .hdr files is that it is rounded to the nearest integer, so
it can not set the positions of the images to sub-voxel accuracy.
Best regards,
-John
| I use HDR edit to set the coordinates of the origin to the anterior
| commisure on both my anatomic images and epi images. This works fine
| since when I examine the header with spm_hread, the correct values are
| present in the headers.
| However, when I display the images using DISPLAY, the coordinates of the
| origin seem to be more or less in the middle of the volume rather than
| the values contained in the header. Why is this?
| Also, when I specify a model and compute the results, the origin of the
| datasets displayed on the glass brains is in the middle of the volume
| rather than at the coordinates contained in the headers of the epi
| images. Why is this?
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