A method and device for detecting an overhead cable from an aerial vessel, for instance from a helicopter in motion, and specifically for use in a landing preparing procedure. The method includes providing, from a camera arranged in the aerial vessel, a plurality of images of an area beneath the aerial vessel when the aerial vessel is in motion; detecting lines in the images; determining if the lines represent lines at ground level or lines at a level above ground level; and determining if a line at a level above ground level represents a possible overhead cable. The step of detecting lines in the images may include a modified SUSAN algorithm. The step of determining if the lines represent lines at ground level or lines above ground level may include parallax calculation.