Department of Mechanical Engineering University of Fukui Fukui Japan;
College of Industrial Engineering Wenzhou University Wenzhou 325007 China;
Division of Mechanical Science School of Engineering Hokkaido University Kitaku Japan;
Fiber Amenity Engineering Course Graduate School of Engineering University of Fukui Fukui Japan;
multiphase flow; flow visualization; image separation; image reconstruction; Particle Image Velocimetry (PIV); triangular Bézier patch;