Results from code below (115 fMRI HCP files)
Vol - read
Elapsed time is 4.536723 seconds.
Slice - read
Elapsed time is 4.581537 seconds.
Vol - read and write
Elapsed time is 8.776489 seconds.
Slice - read and write
Elapsed time is 71.972148 seconds.
function cspm_test_spmreadwrite ( P1, P2 )
% Testing reading and writing by slice vs volume
% Copy same files into two different folders
% Select each set of files (P1, P2)
V1 = spm_vol(P1);
V2 = spm_vol(P2);
disp('Vol - read ')
tic
Y1 = spm_read_vols(V1);
toc
disp('Slice - read')
tic
nscan = length(V2);
Y2 = zeros([V2(1).dim nscan]);
dim12 = V2(1).dim(1:2);
for z = 1:V2(1).dim(3)
for i = 1:nscan
Y2(:,:,z,i) = spm_slice_vol(V2(i),spm_matrix([0 0 z]),dim12,0);
end
end
toc
disp('Vol - read and write')
tic
Y1 = spm_read_vols(V1);
for i = 1:nscan
spm_write_vol(V1(i),Y1(:,:,:,i));
end
toc
disp('Slice - read and write')
tic
nscan = length(V2);
Y2 = zeros([V2(1).dim nscan]);
dim12 = V2(1).dim(1:2);
for z = 1:V2(1).dim(3)
for i = 1:nscan
Y2(:,:,z,i) = spm_slice_vol(V2(i),spm_matrix([0 0 z]),dim12,0);
end
for i = 1:nscan
spm_write_plane(V2(i),Y2(:,:,z,i),z);
end
end
toc
end