Method and device for inspecting sewer pipe walls

摘要

A support frame (10) for a television camera (16) has two laser modules (32) which direct two parallel, narrowly focused light beams onto a wall surface to be detected. The spacing of the light points on the wall is equal to the axial spacing of the two lasers (32) on the camera (16). If the camera (16) determines a crack in the wall, said crack is visualised on a monitor together with the two light points, imaged on the monitor, of the laser (32). It is possible independently of the distance of the camera from the wall to be investigated for the dimensions of the crack imaged on the monitor to be estimated or measured and brought into a relationship with the spacing of the two imaged light points and - since the actual spacing of the two light points on the wall is known - to recalculate the actual dimensions of the crack. <IMAGE>