斜め画像を使った河床粒度分布調査における撮影俯角推定技術と精度検証

抄録

New grain sizing, image processing method with digital photography, is modern analysis by using computer, and has ever been improved to keep the result accurate in any conditions of river bed. Because it is the characteristic of image processing method not to take time for the analysis, the observation to take photos requires effort the most.

For the purpose of improving efficiency, we suggest two techniques. One is estimating photography angle from shape of a quadrate frame in an inclined image and the other is calibration of distortion with optical theorem, which supposes that grain is hemisphere body. In the result, the error of estimated angle is less than 1.5 degrees in any cases, and distortion calibrating shows the better fix than the traditional method, sieve analysis test.