  We have modified the iterative procedure introduced by Lin et al. (2016), to
systematically combine the submm images taken from ground based (e.g., CSO,
JCMT, APEX) and space (e.g., Herschel, Planck) telescopes. We applied the
updated procedure to observations of three well studied Infrared Dark Clouds
(IRDCs): G11.11-0.12, G14.225-0.506 and G28.34+0.06, and then performed
single-component, modified black-body fits to derive $\sim$10$"$ resolution
dust temperature and column density maps. The derived column density maps show
that these three IRDCs exhibit complex filamentary structures embedding with
rich clumps/cores. We compared the column density probability distribution
functions (N-PDFs) and two-point correlation (2PT) functions of the column
density field between these IRDCs with several OB cluster-forming regions.
Based on the observed correlation and measurements, and complementary
hydrodynamical simulations for a 10$^{4}$ $\rm M_{\odot}$ molecular cloud, we
hypothesize that cloud evolution can be better characterized by the evolution
of the (column) density distribution function and the relative power of dense
structures as a function of spatial scales, rather than merely based on the
presence of star-forming activity. Based on the small analyzed sample, we
propose four evolutionary stages, namely: {\it cloud integration, stellar
assembly, cloud pre-dispersal and dispersed-cloud.} The initial {\it cloud
integration} stage and the final {\it dispersed cloud} stage may be
distinguished from the two intermediate stages by a steeper than $-$4 power-law
index of the N-PDF. The {\it cloud integration} stage and the subsequent {\it
stellar assembly} stage are further distinguished from each other by the larger
luminosity-to-mass ratio ($>$40 $\rm L_{\odot}/M_{\odot}$) of the latter.
