“…To solve this problem, phase retrieval holography using two or more cameras has been proposed (Liu and Scott, 1987;Zhang et al, 2003). The present authors have used this method to measure microparticles (Tanaka et al, 2016), microbubbles (Kubonishi et al, 2018), and microdroplets (Nakatani et al, 2019;Tanaka et al, 2019b). However, practical usage of Gabor holography and phase retrieval holography is limited by the huge execution time for volumetric reconstruction.…”