During heterogenous catalytic reactions, far from thermodynamic equilibrium, the reactants adsorbed on a surface, may exibit phenomena of intrinsic spatial and temporal self-organization. The Photo Emission Electron Microscope is capable of imaging the distribution of the adsorbed species in real time. Two new experimental methods, that will finally close the pressure gap between investigations under UHV conditions and the reality of catalysis, have been developed to investigate pattern formation during surface reactions. The Ellipso-Microscopy for Surface Imaging is sensitive even to submonolayer quantities of atoms adsorbed on a metal surface. Comparable sensitivity is achieved by the Reflection Anisotropy Microscopy which measures the variation of the normal-incidence reflectivity of linearly polarised light. The higher reaction rates at elevated pressures and under a small temperature gradient across the sample will lead to new phenomena in pattern formation and might also allow new insights to the fundamental processes.