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File Formats - Sourcemap
Description
Source map files contain the estimated sources
obtained from linear estimation techniques, such as PRoMS and LORETA.
Position and dipole moment information is included in the file.
Optionally, the inverse operator may be included in binary format.
Comments
Lines beginning with '//' is a comment line,
and will be ignored. Comment lines are only valid between location fields,
not within location fields.
Header
The header consists of the entries shown in Table A-1 (in mandatory
sequence):
|
Name |
Format |
Description |
|
option |
%x |
bitmap set by program |
|
state |
%x |
bitmap set by program |
|
condition number |
%f |
parameter set by program |
|
head radius (out, in) |
%f %f |
outer, inner head radius (meters) |
|
display scale factors |
%f %f %f%f
%f%f |
parameters set by program |
|
#X, #Y, #Z |
%d %d %d |
number of voxels in x, y, z directions |
|
start_X, start_Y, start_Z |
%f %f %f |
start location for source region (xyz, meters) |
|
del_X, del_Y, del_Z |
%f %f %f |
voxel size (xyz, meters) |
|
model type |
%x |
|
Table A-1
The header is followed by a list of source
locations. The locations are grouped by (xy) planes, and then by rows
(constant y). Both the planes and rows have their own header fields
Planes
The plane header is defined in Table A-2. It consists of 3 fields.
|
Name |
Format |
Description |
|
state |
%x |
bitmap set by program |
|
#Y, #X |
%d %d |
number of voxels in y, x directions |
Table A-2
Rows
The row header is defined in Table A-3. It consists of 2 fields.
|
Name |
Format |
Description |
|
state |
%x |
bitmap set by program |
|
#X |
%d |
number of voxels in x direction |
Table A-3
Locations
There is a location field corresponding to each location in the source
region, defined in Table A-3. It consists of 7 fields.
|
Name |
Format |
Description |
|
weight |
%g |
prior likelihood |
|
inverse |
%g |
source strength (ampere meters) |
|
maximum index |
%d |
0-2: maximum index for PRoMS eigenvector
3: single eigenvector (LORETA) |
|
state |
%x |
state|0x1 <=> in head state|0x2 <=> in eye
state|0x4 <=> compressed format
(if neither bit 1 nor bit 2 is set, the location is outside the
head) |
|
eigenvector |
%g %g %g |
coordinates of unit solution vector (xyz) when stored in compressed
format .
If not in compressed format (unusual), this field will contain a 3x3
matrix of eigenvectors, followed by a 3x1 matrix of eigenvalues.
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Table A-3
Example
The following example includes the first two locations from
a file. There are 5 planes, each of 9 rows and 9 columns. A 3shell sphere
model was used for fitting. The first 3 voxels are outside the head, and
their vector components are undefined.
3 80
1
1442 11726
0.37898
0
0
2.76715e-09 1 140 3 3 1
9 9 5
-0.08 -0.08 0.02
0.02 0.02 0.02
8
1002
9 9
2
9
0 0 -1 4
0 0 0
0 0 -1 4
0 0 0
0 0 -1 4
0 0 0
0 5.681319e-10 3 5
0.856231 0.052773 0.513891
0 5.079521e-10 3 5
0.669451 -0.077987 0.738752
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