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Application properties of polymer foams are closely related to their morphology. Experimental characterization and subsequent morphological analysis thus represent essential tools for their investigation. Spatially three-dimensional porous structures of four closed-cell polyurethane foams are reconstructed using the X-ray micro-tomography (μCT) imaging with the spatial resolution of 2 μm. Challenges associated with insufficient μCT resolution (e.g., reconstruction of thin walls of polymer) are addressed and the methodology allowing their overcoming is presented. Foam anisotropy is characterized (i) using the lineal-path function as a common statistical descriptor of morphology, and (ii) by the spatial orientation vector whose evaluation is newly developed in this paper. Foam porosity and cell size distribution evaluated both from the 2D cross-section slices and from the complete 3D data are compared. Additionally, the porosity is compared with the experimentally measured values. It is demonstrated that 3D volumetric data are advantageous for a proper morphological characterization of the foam. [ABSTRACT FROM AUTHOR]