impyramid - Image pyramid reduction and expansion
imout=impyramid(imin,direction) computes a Gaussian pyramid reduction or expasion of imin by one level. Direction can be 'reduce' or 'expand'. If imin is mxn and direction is 'reduce', then the size of imout is ceil(m/2)xceil(n/2). If direction is 'expand', then the size of imout is (2xm)x(2xn).
Compute a four-level multiresolution pyramid of the 'lena' image.
im0 = imread(SCI + '/contrib/sivp/images/lena.png');
im1 = impyramid(im0, 'reduce');
im2 = impyramid(im1, 'reduce');
im3 = impyramid(im2, 'reduce');
imshow(im0);
imshow(im1);
imshow(im2);
imshow(im3);