TY - CHAP A1 - Bühler, P. A1 - Leandro, J. A1 - Bung, Daniel B. A1 - Lopes, P. A1 - Carvalho, R. T1 - Measuring void fraction of a stepped spillway with non-intrusive methods using different image resolutions T2 - 2nd International Workshop on Hydraulic Structures : Data Validation : Coimbra, Portugal, 8-9 May 2015 Y1 - 2015 SP - 1 EP - 8 ER -