N = [128 128];
L = [1 1];
h = L./N;
[x1 x2] = ndgrid(0:h(1):L(1)-h(1),0:h(2):L(2)-h(2));

load marmousi.dat
m = reshape(marmousi,122,384);
m = m/max(max(m));
m = m([ones(1,6), 1:122],195:322);
m = m .* exp(-(x2-.5).^6/(.004)) .* exp(-(x1-.5).^6/(.004));