srf.backtovmr
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— | srf.backtovmr [2010/07/25 13:07] (current) – created jochen | ||
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+ | ====== srf.BackToVMR ====== | ||
+ | |||
+ | ===== Motivation ===== | ||
+ | After creating/ | ||
+ | |||
+ | ===== Requirements ===== | ||
+ | You simply need the surface object you wish to visualize in voxel space. | ||
+ | |||
+ | ===== Method reference (' | ||
+ | < | ||
+ | |||
+ | | ||
+ | |||
+ | Input fields: | ||
+ | |||
+ | | ||
+ | .fillmode | ||
+ | .nfrom | ||
+ | .nstep | ||
+ | .nto | ||
+ | .res VMR resolution, either of {1} or 0.5 | ||
+ | .triovsmp | ||
+ | |||
+ | | ||
+ | |||
+ | | ||
+ | |||
+ | ===== Options ===== | ||
+ | Options are passed as a struct. In the default case, a clearly visible layer (between one and two voxels usually) will be drawn. Depending on the mesh resolution, you might want to increase the triangle oversampling factor, for instance. | ||
+ | |||
+ | ==== .fillmode ==== | ||
+ | The fillmode determines how the VMR values will be filled. For nearest, each determined coordinate (vertex + multiplied normal vector, potentially triangular subsampled), | ||
+ | |||
+ | ==== .nfrom, .nstep, and .nto ==== | ||
+ | These three parameters determine how many sampling passes are performed and how far along the normal vector the sampling occurs. This is helpful if you wish to fill a thicker layer in voxel space, e.g. for creating a mask that covers more space. | ||
+ | |||
+ | ==== .res ==== | ||
+ | In case you are working in 0.5mm resolution (BrainVoyager' | ||
+ | |||
+ | ==== .triovsmp ==== | ||
+ | This parameter sets the triangular oversampling factor. The higher this value is, the more points within each triangle will be sampled. For example, with an oversampling factor of 5, each side of the triangle is split 5-fold and the meeting points of the parallel lines will be sampled. | ||
+ | |||
+ | ===== Output example ===== | ||
+ | This image represents the ICBM normalized left-hemisphere (radiological convention!) display of the colin_LH_ICBMnorm.srf file overlaid on the colin_brain_ICBMnorm.vmr (using a 6-times oversampling in triangles to cope with differences in triangle size). The interior has then been flood-filled with a code of 240 for voxels in the range 150 through 225. | ||
+ | |||
+ | {{: | ||
srf.backtovmr.txt · Last modified: 2010/07/25 13:07 by jochen