SurfStatROI

ROI on the surface or volume with a given centre and radius.

 Usage: ROImask = SurfStatROI( centre, radius, surf );
 
 centre      = id number of vertex, or 
               3 x 1 vector of [x; y; z] coordinates in mm.
 radius      = radius, mm.
 surf.coord  = 3 x v matrix of coordinates of surface.
 or
 surf.lat    = nx x ny x nz array, 1=in, 0=out, clamped to the mask.
 surf.vox    = 1 x 3 vector of voxel sizes in mm of the clamped mask.
 surf.origin = position in mm of the first voxel of the clamped mask.

 maskROI = 1 x v vector, 1=inside ROI, 0=outside.

0001 function maskROI = SurfStatROI( centre, radius, surf );
0002 
0003 %ROI on the surface or volume with a given centre and radius.
0004 %
0005 % Usage: ROImask = SurfStatROI( centre, radius, surf );
0006 %
0007 % centre      = id number of vertex, or
0008 %               3 x 1 vector of [x; y; z] coordinates in mm.
0009 % radius      = radius, mm.
0010 % surf.coord  = 3 x v matrix of coordinates of surface.
0011 % or
0012 % surf.lat    = nx x ny x nz array, 1=in, 0=out, clamped to the mask.
0013 % surf.vox    = 1 x 3 vector of voxel sizes in mm of the clamped mask.
0014 % surf.origin = position in mm of the first voxel of the clamped mask.
0015 %
0016 % maskROI = 1 x v vector, 1=inside ROI, 0=outside.
0017 
0018 if isfield(surf,'coord')
0019     if length(centre)==1
0020         id=centre;
0021         centre=surf.coord(:,id);
0022     end
0023     d2=sum((centre*ones(1,size(surf.coord,2))-surf.coord).^2);
0024     maskROI=d2<radius^2;
0025 else
0026     if length(centre)==1
0027         id=centre;
0028         vid=int32(cumsum(surf.lat(:)).*surf.lat(:));
0029         [i,j,k]=ind2sub(find(vid==id),size(surf.lat));
0030         centre=(([i,j,k]-1).*surf.vox+surf.origin)';
0031     end
0032     dim=size(surf.lat);
0033     x0=((1:dim(1))-1)*surf.vox(1)+surf.origin(1);
0034     y0=((1:dim(2))-1)*surf.vox(2)+surf.origin(2);
0035     z0=((1:dim(3))-1)*surf.vox(3)+surf.origin(3);
0036     [i,j,k]=ndgrid(x0,y0,z0);
0037     coord=[i(surf.lat) j(surf.lat) k(surf.lat)]';
0038     d2=sum((centre*ones(1,size(coord,2))-coord).^2);
0039     maskROI=d2<radius^2;
0040 end
0041 
0042 return
0043 end
0044