  We investigate the non-Gaussian signatures in Cosmic Microwave Background
(CMB) maps induced by the intervening large-scale structure through weak
lensing. In order to measure the deviation from the Gaussian behavior of the
intrinsic temperature anisotropies, we use a family of three morphological
descriptors, the so-called Minkowski functionals. We show analytically how
these quantities depend on the temperature threshold, and compare the results
to numerical experiments including the instrumental effects of Planck.
Minkowski functionals can directly measure the statistical properties of the
displacement field and hence provide useful constraints on large-scale
structure formation in the past.
