[AIP MULTIPHASE FLOW: THE ULTIMATE MEASUREMENT CHALLENGE: Proc.of The 5th Int. Symp. on Measurement Techniques for Multiphase Flows (5th ISMTMF); 2nd Int. Wrkshp.on Process Tomography (IWPT-2) (As a part of ISMTMF); 5th ISMTMF/IWPT-2, 2006-Macau/Zhuhai) - Macau (China) (10-13 December 2006)] AIP Conference Proceedings - Characterization of Window Functions for Regularization of Electrical Capacitance Tomography Image Reconstruction