leaves
system:sage

<p>Image source: <a href="http://commons.wikimedia.org/wiki/Ginkgo_biloba">http://commons.wikimedia.org/wiki/Ginkgo_biloba</a></p>

{{{id=1|
import pylab
A_image = pylab.mean(pylab.imread(DATA + 'leaves.png'), 2)
@interact
def svd_image(num_eigenvals=(20,(1..100)), display_axes=True):
    i = num_eigenvals
    u,s,v = pylab.linalg.svd(A_image)
    A     = sum(s[j]*pylab.outer(u[0:,j], v[j,0:]) for j in range(i))
    g = graphics_array([matrix_plot(A),matrix_plot(A_image)])
    show(g, axes=display_axes, figsize=(8,5))
    html('<b>The leaves of a tree beloved by a wise sage,<br>compressed by Sage using %s eigenvalues</b>'%i)
///
}}}

{{{id=2|

///
}}}