1. A method for locating and marking flaws on a surface of a three-dimensional object ( 2 ), said method comprising the steps of: a) detecting and locating at least one flaw on the surface of the three-dimensional object by taking at least one picture with at least one optical image-taking device ( 3 , 4 ), so that the at least one flaw appears in the at least one picture; b) determining at least one location of the at least flaw on the surface of the three-dimensional object from the at least one picture using design data related to the object ( 2 ), optical imaging properties of the at least one optical image-taking device ( 3 , 4 ), and a position of the at least one optical image-taking device ( 3 , 4 ) and a position of the object ( 2 ) when the at least one picture is taken; c) transferring the at least one location of the at least one flaw determined in step b) to a marking device ( 15 ); d) determining a start path traversable by the marking device ( 15 ) from the design data related to the object ( 2 ), from position data and from previously-defined, permissible areas of movement of the marking device ( 15 ); e) moving the marking device ( 15 ) over the object ( 2 ) to the at least one location of the at least one flaw; and then f) marking the at least one location of the at least one flaw on the object ( 2 ) with the marking device ( 15 ); wherein the at least one optical image-taking device ( 3 , 4 ), the object ( 2 ) and at least one of respective displacement devices ( 9 , 10 , 16 ) for moving the at least one optical image-taking device ( 3 , 4 ), the object ( 2 ), and the marking device ( 15 ) are three-dimensionally calibrated to each other.