Large-scale Particle Image Velocimetry (LSPIV) implementation on smartphone

Ryota Tsubaki, Ichiro Fujita, Kwonkyu Yu, Marian Muste

Thursday 2 july 2015

16:45 - 17:00h at Africa (level 0)

Themes: (T) Special session, (ST) Acoustic monitoring of flow, turbulence and river discharge

Parallel session: 13F. Special session: Acoustic monitoring of flow, turbulence and river discharge

Modern smartphone is a bundle of sophisticated sensors under control of a central processing unit (CPU) with network accessibility. LSPIV (large-scale particle image velocimetry) is an image based method to measure the velocity distribution on water surface. By introducing the assumption of the vertical velocity distribution and cross-sectional profile data, the flow rate through the channel can be estimated. Conventional LSPIV consists of an independent camera system and data processing unit, and requires explicit ortho-rectification using ground control points (GCPs) to correlate the image coordinate to physical coordinate. The surveying of all GCPs are required before the ortho-rectification implementation, and this limits flexibility of LSPIV application in urgent measurement in remote area. These demands are usual for the flood observation. In this study, we develop the system consisting of smartphone and application software that utilizes sensors including video camera, global positioning sensor (GPS), acceleration sensor and gyros (Yu et al. 2014). In this system, the image captured by the camera is automatically ortho-rectified immediately without use of GCPs. The performance of the developed system is verified through both flume and field experiments. Finally, the future plan is described.