Method for detection of objects in abundant water conditions, involves first spectral reflection survey of area to be investigated of frequencies around water absorption band

The method for detection of objects in abundant water conditions involves a first spectral reflection survey of an area to be investigated of frequencies around a water absorption band. A second spectral reflection survey is then made of the area of the frequencies around a reference band. The location of the water-holding objects, such as vegetation, is then fixed by the determination of the zones where the first and second surveys differ. First and second cameras (1,2) with first and second filters (3,4) are used. So that both cameras can view the same scene, a mirror (5) and a part mirror (6) are used. For focussing a lens unit (7) is employed and the system has an optical axis (8).