Author(s): I. Fujita; H. Akita; M. Shimono
Linked Author(s): Ichiro FUJITA
Keywords: Velocity Measurement; Video Image Analysis; LSPIV; STIV; Clinometer
Abstract: In applying image-based techniques such as the large-scale particle image velocimetry (LSPIV) or the space-time image velocimetry (STIV) to river flow measurements, the images usually taken from a riverbank have to be rectified by using several ground control points (GCPs) set along the river. However, the rectification process sometimes generates erroneous results due to a measurement error of GCP or even when the measurements are correct, rectified images are difficult to use for a very wide rivers viewed from a low-height elevation due to the lack of enough special resolution. Furthermore, appropriate setting of GCPs becomes difficult for the flow measurement of deep valley. Therefore, we developed a correction method to generate and modify error-included rectified images by using functional relation of the collinear equation. Moreover, a new method by using a digital clinometer while shooting is proposed that can reduce the number of GCP in the actual field measurements.