REGION - Group Voxels into Regions

REGION is a collection of routines for manipulating 3D voxel data. As part of a project, we had to take a file of voxel data representing a brain scan. Each voxel had an integer value representing the intensity of a signal. Only voxels with an intensity above a certain value were to be considered. Those voxels were then grouped into contiguous regions.

A further complication was the desire to be able to pick include an enclosing surface image of the brain, project the internal regions out along a line from a point to the surface, and mark the surface with the color associated with the region. Some of the routines in this package are associated with that task.

A simple routine called IVOXEL_TO_OBJ allows you to take a voxel array and create a corresponding OBJ 3D graphics file.

Files you may copy include:

• region.f90, the source code;
• region_prb.f90, the calling program;
• region_prb.out, the sample output;
• roi.ascii, the sample data file.

The list of routines includes:

• FACE_PRINT prints the nodes that define one face of a voxel.
• GET_UNIT returns a free FORTRAN unit number.
• IVOXEL_BOUND_PRINT writes bounding faces to an OBJ file.
• IVOXEL_COUNT_POSITIVE counts the positive entries in a voxel array.
• IVOXEL_PLOT prints out a typewriter plot of the Z slices.
• IVOXEL_PLOT2 prints out a typewriter plot of the regions.
• IVOXEL_PLOT3 prints out a typewriter plot of data/100.
• IVOXEL_READ reads MRI data from an ASCII file, one item per line.
• IVOXEL_SUM sums the entries in a voxel array.
• IVOXEL_THICKEN "thickens" the voxels.
• IVOXEL_THRESH zeroes out array entries below a given threshhold.
• IVOXEL_TO_OBJ writes out an OBJ file from a voxel array.
• IVOXEL_TO_REGION arranges a set of voxels into contiguous regions.
• IVOXEL_WRITE writes MRI data to an ASCII file, one item per line.
• NODE_PRINT prints the nodes that define one face of a voxel.
• REGION_BLANK zeroes out voxels in a particular numbered region.
• REGION_CENTER computes the centers of mass of the regions.
• RVOXEL_TO_IVOXEL copies real voxel data into an integer voxel array.
• TRANSPORT transports voxels to the boundary, counts intermediate hits.
• TRANSVOX transports one voxel to the boundary.
• VOXEL_INDEX_STEP computes indices of voxels along a line from a given point.
• VOXEL_NODES returns the indices of the nodes of a voxel.

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