Abstract
In surface investigation of the concrete structures, an investigator has to often access a high place. In such a case, methods such as temporary scaffold and rope access are adopted. However, these methods are expensive, and danger is accompanied. In recent years, the performances of a digital camera and image processing technology have accomplished remarkable progress. So the authors applied these technologies to the remote investigation technique for the concrete structures, and evaluated applicability of the technique for the dam where investigation area is larger and complicated.
