| 摘要 |
PROBLEM TO BE SOLVED: To enable the presence or absence of crack to be accurately detected even if a concrete wall surface or the like is smeared with soot or the like to make any crack therein difficult to visually recognize.SOLUTION: Light irradiating means 3 irradiates a concrete wall surface 2 with red, blue or green light, and photographic means 4 photographs the wall surface. RGB values r, g and b of respective pixels in a picture obtained by the photographic means 4 are converted by color saturation calculating means 5 into color saturation S, and crack determining means 6 determines the presence or absence of crack on the basis of the values of the color saturation S. Even if the concrete wall surface or the like is smeared with soot or the like to make any crack therein difficult to visually recognize, the crack determining means 6 can accurately detect the presence or absence of crack since the value of the color saturation S in the presence of a crack significantly differs from that in the absence of a crack. |
