We provide a numerical scheme for determining the Ginzburg-Landau free energy density directly from analysis of real or simulated images of phase evolving polymers. Our technique is robust and rapidly converges without requiring that the system reach equilibrium. The coefficients for the functional thus obtained agree with well-known mean-field trends. To our knowledge, this is the first prescription for specifying both the magnitudes and temperature dependencies for all of the free energy coefficients from microscopic models. (c) 2006 Wiley Periodicals, Inc.