GPS‐level accurate camera localization with HorizonNet. Issue 6 (23rd December 2019)

• Record Type: Journal Article
• Authors: Grelsson, Bertil; Robinson, Andreas; Felsberg, Michael; Khan, Fahad Shahbaz
• Is Part Of: Journal of field robotics. Volume 37:Issue 6(2020)
• Page Start: 951
• Page End: 971
• Publication Date: 2019-12-23
• Subjects: GPS‐denied operation -- localization -- marine robotics; Robots, Industrial -- Periodicals; Automatic control -- Periodicals; 629.892
• DOI: 10.1002/rob.21929
• Languages: English
• ISSNs: 1556-4959

Abstract

Abstract: This paper investigates the problem of position estimation of unmanned surface vessels (USVs) operating in coastal areas or in the archipelago. We propose a position estimation method where the horizon line is extracted in a 360° panoramic image around the USV. We design a convolutional neural network (CNN) architecture to determine an approximate horizon line in the image and implicitly determine the camera orientation (the pitch and roll angles). The panoramic image is warped to compensate for the camera orientation and to generate an image from an approximately level camera. A second CNN architecture is designed to extract the pixelwise horizon line in the warped image. The extracted horizon line is correlated with digital elevation model data in the Fourier domain using a minimum output sum of squared error correlation filter. Finally, we determine the location of the maximum correlation score over the search area to estimate the position of the USV. Comprehensive experiments are performed in field trials conducted over 3 days in the archipelago. Our approach provides excellent results by achieving robust position estimates with global positioning system (GPS)‐level accuracy in previously unvisited test areas.