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Hello FreeSurfer Developers,
I am trying to reconstructing surface of monkey brain.
I have got surface files, such as ?h.white, ?h.pial, ?h.area and so on. However, I found the surface light was abnormally dark(as shown in following picture), it seems like that the light source was inside the brain.
And I found the RAS and SurfaceRAS coordiantes were different.
I got the surface files as following steps:
(1) I got the wm.mgz file manually;
(2) I filled the wm.mgz and changed the values in left and right hemispheres to 255 and 127, respectively;
(3) I generated ?h.orig via command "mri_tessellate filled.mgz 255 lh.orig -n"
Then I found RAS and SurfaceRAS coordiantes in ?h.orig were different.
Which steps did I made a mistake? The voxel size of raw image was 0.5*0.5*0.5 mm, was the image resolution the cause?
Thank you very much!
zhiwei
here is the information of raw image:
Volume information for T1.mgz
type: MGH
dimensions: 137 x 175 x 107
voxel sizes: 0.500000, 0.500000, 0.500000
type: FLOAT (3)
fov: 87.500
dof: 0
xstart: -34.2, xend: 34.2
ystart: -43.8, yend: 43.8
zstart: -26.8, zend: 26.8
TR: 0.00 msec, TE: 0.00 msec, TI: 0.00 msec, flip angle: 0.00 degrees
nframes: 1
PhEncDir: UNKNOWN
FieldStrength: 0.000000
ras xform present
xform info: x_r = 1.0000, y_r = 0.0000, z_r = 0.0000, c_r = 0.5000
: x_a = 0.0000, y_a = 1.0000, z_a = 0.0000, c_a = -6.0000
: x_s = 0.0000, y_s = 0.0000, z_s = 1.0000, c_s = 3.7500
talairach xfm :
Orientation : RAS
Primary Slice Direction: axial
voxel to ras transform:
0.5000 0.0000 0.0000 -33.7500
0.0000 0.5000 0.0000 -49.7500
0.0000 0.0000 0.5000 -23.0000
0.0000 0.0000 0.0000 1.0000
voxel-to-ras determinant 0.125
ras to voxel transform:
2.0000 0.0000 0.0000 67.5000
0.0000 2.0000 0.0000 99.5000
0.0000 0.0000 2.0000 46.0000
0.0000 0.0000 0.0000 1.0000