nifti2_data_format
nifti2_data_format > RE: NIFTI-2 proposal
Mar 1, 2011 02:03 AM | Randall Frank
RE: NIFTI-2 proposal
Originally posted by Jochen Weber:
The changes seem fine to me as well and I agree with other comments like the above. IMHO, what is imporatant here is that the interpretation of the fields remains true to NIFTI-1 (and your proposal reflects that). This keeps the "business logic" of the apps the same as that in NIFTI-1, which is the biggest win. As long as you are breaking binary compatibility (early arguments for NIFTI), I would encourage more aggressive changes to the header as well. Drop unused fields, standardize the types of the fields, use a page aligned header size (given the size of data files implicit in the proposal, make the header 4k with space for new things) and use a new filename extension. Most of us will read this through another library and as long as the field interpretation does not change, I just need to know offsets and sizes of the fields, along with magic and an endian test to modify my readers. In any case, I like the change.
rjf.
Copy that :) changes seem reasonable and
straight forward.
I was just
wondering ... is there a particular reason to keep any of the unused fields (see char data_type[10] or db_name[18] from http://nifti.nimh.nih.gov/pub/dist/src/n... for instance)? I would think it's easy enough to set these to default values as part of an output filter that saves a NIFTI-2 struct/image as a NIFTI-1 or Analyze 7.5 header stream to disk; in that case, maybe a total header size (incl. a null-extension) of 512 could be achieved, which might make mapping into a compound object (where actual image data is located in the same file on disk) a little more efficient, given that accessing data slice-by-slice on harddisks still makes it more likely to hit a block boundary for raw images with a 64x64 or 128x128 matrix...
/jochen
I was just
wondering ... is there a particular reason to keep any of the unused fields (see char data_type[10] or db_name[18] from http://nifti.nimh.nih.gov/pub/dist/src/n... for instance)? I would think it's easy enough to set these to default values as part of an output filter that saves a NIFTI-2 struct/image as a NIFTI-1 or Analyze 7.5 header stream to disk; in that case, maybe a total header size (incl. a null-extension) of 512 could be achieved, which might make mapping into a compound object (where actual image data is located in the same file on disk) a little more efficient, given that accessing data slice-by-slice on harddisks still makes it more likely to hit a block boundary for raw images with a 64x64 or 128x128 matrix...
/jochen
The changes seem fine to me as well and I agree with other comments like the above. IMHO, what is imporatant here is that the interpretation of the fields remains true to NIFTI-1 (and your proposal reflects that). This keeps the "business logic" of the apps the same as that in NIFTI-1, which is the biggest win. As long as you are breaking binary compatibility (early arguments for NIFTI), I would encourage more aggressive changes to the header as well. Drop unused fields, standardize the types of the fields, use a page aligned header size (given the size of data files implicit in the proposal, make the header 4k with space for new things) and use a new filename extension. Most of us will read this through another library and as long as the field interpretation does not change, I just need to know offsets and sizes of the fields, along with magic and an endian test to modify my readers. In any case, I like the change.
rjf.
Threaded View
| Title | Author | Date |
|---|---|---|
| Mark Jenkinson | Feb 28, 2011 | |
| Mark Jenkinson | Mar 15, 2011 | |
| Cinly Ooi | Mar 15, 2011 | |
| Cinly Ooi | Mar 2, 2011 | |
| Ged Ridgway | Mar 7, 2011 | |
| Jon Clayden | Mar 5, 2011 | |
| Cinly Ooi | Mar 1, 2011 | |
| Andrew Janke | Mar 1, 2011 | |
| Cinly Ooi | Mar 2, 2011 | |
| Satrajit Ghosh | Mar 5, 2011 | |
| Cinly Ooi | Mar 1, 2011 | |
| Cinly Ooi | Mar 1, 2011 | |
| Cinly Ooi | Mar 1, 2011 | |
| Cinly Ooi | Mar 1, 2011 | |
| Denis Rivière | Feb 28, 2011 | |
| Cinly Ooi | Mar 1, 2011 | |
| Brandon Whitcher | Mar 1, 2011 | |
| Satrajit Ghosh | Feb 28, 2011 | |
| Jonas Larsson | Mar 1, 2011 | |
| Mark Horsfield | Mar 1, 2011 | |
| Andrew Janke | Mar 1, 2011 | |
| Jochen Weber | Feb 28, 2011 | |
| Randall Frank | Mar 1, 2011 | |
| Michael Martinez | Feb 28, 2011 | |
| Cinly Ooi | Feb 28, 2011 | |
| Chris Rorden | Feb 28, 2011 | |