This is an example image with a fourier domain scaling algorithm applied (x4). The thumbnail before scaling up was a 40 by 40 scaled down version of the Wikipedia Commons photograph 'Green Sea Shell' by James Petts %Matlab code, after import of File:40 by 40 thumbnail of 'Green Sea Shell'.png : i=1; shell_i(:,:,i)=(interpft(interpft(shell(:,:,i),size(shell,2)*2,2),size(shell,1)*2,1)); %fourier interpolation 2D / padding with 0 freq components i=2; shell_i(:,:,i)=(interpft(interpft(shell(:,:,i),size(shell,2)*4,2),size(shell,1)*4,1)); i=3; shell_i(:,:,i)=(interpft(interpft(shell(:,:,i),size(shell,2)*4,2),size(shell,1)*4,1)); shell_i=; shell_i=shell_i-min(shell_i(:)); shell_i=shell_i./max(shell_i(:)); export_fig '40 by 40 thumbnail of 'Green Sea Shell' fourier interpolated.png' '-png' '-native' '-a1'