Field test of beach litter monitoring by commercial aerial drone

The visual survey is the commonest method to quantify and characterize beach litter. However, it is very labour intensive and difficult to carry out on beaches which are remote or difficult to access. We herein report an alternative approach for monitoring beach litter using an unmanned aerial vehicle (UAV), or aerial drone, with automated image requisition and automatic image processing. Litter of different sizes and colours, and made from different materials were placed randomly on four beaches. Images of beaches with different substrates were obtained by the drone at different heights and light conditions. Litter on the beaches was identified from the photos by untrained personnel with the highest accuracy of >90%. The quantification of beach litter was three times faster using the drone than visual census. This study indicates the potential of using the drone as a cost-effective and an efficient sampling method in routine beach litter monitoring programs.