Evaluation of Images Obtained with the Micasense Sensor to Estimate Bathymetry in Optically Shallow Water

Abstract

The bathymetric survey is an integral part of the study of hydrography and consequently of the existing water bodies. Lately, the dissemination of the importance of preserving existing water bodies on the planet has been well known. In this context, bathymetric surveys are the key to calculating silting over the years, estimating volume, erosion at the edges, calculating suspended sediments, among others. These studies are usually performed using echo sounders, which use the sound wave to obtain depth. However, these are time consuming and most of the time have a high cost. Thus, with technological advances, numerous works in this area have already been done with orbital images and the emergence of RPA's (Remotely Pilot Aircraft) systems coupled to aircraft, has brought countless benefits for coastal mapping in the agility, but still not showing efficiency in the cost issue. In view of these issues raised, the present study has as main objective the evaluation of the bathymetry estimate obtained with the Micasense multispectral sensor linked to an unmanned autonomous aircraft. The results found showed that the methodology described, together with the chosen sensor, can be used in several studies of an environmental nature or that aim at the better management of water resources, mainly in clear waters. However, there must be some cautions, especially during the execution of the aerial photogrammetric survey, with attention to the fact that
different locations will contain different rates of Optically Active Components and consequently different results.