function testInterpolation
a = imread('autumn.tif');
a = im2double(rgb2gray(a));

reset (gcf ); % this resets the (get) current figure
hold on; % overlay on current figure
plot ( profile ( a, 100 , 100 , 120 , 120 , 200 , 'linear'), 'b' );
plot ( profile ( a, 100 , 100 , 120 , 120 , 200 , 'nearest'), 'r' );
hold off ;