ULISES: an open source code for extrinsic calibrations and planview generations in coastal video monitoring systems

Abstract

Video monitoring systems have become a powerful and low-cost tool in coastal studies. Extrinsic calibration of the cameras is compulsory to get quantitative information from the images. This paper presents an Open Source Software for extrinsic calibration and for the generation of related products such as planviews and time stacks. The methodology employed for extrinsic calibration minimizes errors comprising ground control points, the camera position, and, whenever is available, the horizon line. The dip of the horizon due to Earth curvature is corrected for. Planview generation is performed in such a way that the user can decide the smoothing degree in the transition zone between cameras. Time stack generation has been designed to save the minimum number of pixels in order to obtain the desired transect in the real world. The reader will find a versatile software meant to manage large data sets in a simple way.