System and method for measuring the distance to an object in water

A system for determining a distance between a boat and at least one object at least partially immerged in a water area, said system comprising:

• a capturing module, configured to be mounted on said boat, said capturing module comprising at least one camera, said at least one camera being configured to generate at least one sequence of images of said water area, a processing module, configured to be embedded onboard said boat, said processing module being configured to receive the at least one sequence of images from said at least one camera, to detect at least one object in said at least one received sequence of images, to determine rotation component values of the at least one camera in a boat reference frame, wherein said boat reference frame is vehicle-carried and comprises a plane defined by the water area and a vertical axis normal to said plane, and to determine the distance between the boat and the at least one detected object using said rotation component values by doing a mapping from a two-dimensional image space to a two-dimensional water surface, said mapping including an inverse projection from said two-dimensional image space to said two-dimensional water surface.