Abstract
Periodic inspection of the tunnel requires too much labor. Because of this, traveling type image measurement vehicle has been attracting attention. It is possible to obtain images of tunnel wall surface in a short time using this equipment. In addition, the crack on the wall can be investigated from deployment image of the tunnel wall with this equipment. However, the work for extracting the crack from the image requires tracing by technicians. In this study, the auhours proposed a method for calculating a level difference height of the concrete wall from the image by irradiation angle of floodlight and width of shade. As a result, it was able to calculate the level difference height of 80-120% of the real height with proposed method. In addition, it could be calculated most accurately with illumination angle of 45°.
