SurfStatCoord2Ind

Converts a vertex index to x,y,z coordinates.

 Usage: coord = SurfStatInd2Coord( ind, surf );

 coord        = c x 3 matrix of coordinates for finding indices thereof. 
 surf.coord   = 3 x v matrix of coordinates.
 or
 surf.lat     = 3D logical array, 1=in, 0=out. 
 surf.vox     = 1 x 3 vector of voxel sizes in mm, [1 1 1] by default.
 surf.origin  = position in mm of the first voxel, [0 0 0] by default.

 ind = c x 1 vector of indices of the nearest vertex to the surface, 
       1-based. If surf is a volume and the point is outside, then ind=0.

0001 function ind = SurfStatCoord2Ind( coord, surf );
0002 
0003 %Converts a vertex index to x,y,z coordinates.
0004 %
0005 % Usage: coord = SurfStatInd2Coord( ind, surf );
0006 %
0007 % coord        = c x 3 matrix of coordinates for finding indices thereof.
0008 % surf.coord   = 3 x v matrix of coordinates.
0009 % or
0010 % surf.lat     = 3D logical array, 1=in, 0=out.
0011 % surf.vox     = 1 x 3 vector of voxel sizes in mm, [1 1 1] by default.
0012 % surf.origin  = position in mm of the first voxel, [0 0 0] by default.
0013 %
0014 % ind = c x 1 vector of indices of the nearest vertex to the surface,
0015 %       1-based. If surf is a volume and the point is outside, then ind=0.
0016 
0017 c=size(coord,1);
0018 ind=zeros(c,1);
0019 if isfield(surf,'coord')
0020     v=size(surf.coord,2);
0021     for i=1:c
0022        dist=sum((surf.coord-repmat(coord(i,:)',1,v)).^2);
0023        ind(i)=find(dist==min(dist));
0024     end
0025 end
0026 if isfield(surf,'lat')
0027     if ~isfield(surf,'vox')
0028         surf.vox=ones(1,3);
0029     end
0030     if ~isfield(surf,'origin');
0031         surf.origin=zeros(1,3);
0032     end
0033     i=round((coord(:,1)-surf.origin(1))/(surf.vox(1)+(surf.vox(1)==0))+1);
0034     j=round((coord(:,2)-surf.origin(2))/(surf.vox(2)+(surf.vox(2)==0))+1);
0035     k=round((coord(:,3)-surf.origin(3))/(surf.vox(3)+(surf.vox(3)==0))+1);
0036     dim=size(surf.lat);
0037     i(i<1 | i>dim(1))=0;
0038     j(j<1 | j>dim(2))=0;
0039     k(k<1 | k>dim(3))=0;
0040     a=i&j&k;
0041     ind=zeros(c,1);
0042     vid=cumsum(surf.lat(:)).*surf.lat(:);
0043     ind(a)=vid(sub2ind(dim,i(a),j(a),k(a)));
0044 end
0045 
0046 return
0047 end
0048