Distance estimation for marine vehicles using a monocular video camera

Abstract

Distance estimation for marine vessels is of vital importance to unmanned ship vehicles (USVs) for navigation and collision prevention. This can be achieved by means such as radar or laser sighting. However, due to constraints of the USV, it may be desired to estimate distance using a monocular camera. In this paper, we propose a method that, given a video of a marine vehicle in a maritime environment and a tracker, estimates the distance of the tracked vehicle from the camera. The method detects the horizon and uses its distance as a reference. It detects the contact point of the vehicle with the sea surface by finding a maximally stable extremal region (MSER). Then, it relies on geometries of the earth and on optical properties of the camera to compute the distance. The method was tested on video footage of several sea maneuvers with an average error of 7.1%.