Avaliação de algoritmos de rastreamento no problema de detecção de pessoas no mar

Abstract

It is known that shark attacks are a constant fear for the population on the beaches of Pernambuco. Many of these attacks are fatal, which calls for some action to be taken, considering that Pernambuco beaches attract thousands of tourists each year. Therefore, researchers from UFRPE initiated a study aiming to develop a system for tracking people in the sea, which would make it possible to alert lifeguards when individuals exceed a designated safe area on the beach, as well as allocate a greater number of these professionals in areas with a higher concentration of people. The system was divided into three stages: image segmentation, detection of beachgoers, and tracking of individuals. This work focuses on the third stage. Tracking people is a complex task with high computational costs. Problems such as changes in lighting conditions, alterations in the direction of targets, and variations in the background are just a few of the difficulties that can be mentioned. Thus, the objective of this research is to evaluate six people tracking algorithms found in the literature using beach images. Firstly, a database of ten videos recorded at Boa Viagem beach in Pernambuco was manually labeled. Then, six algorithms were selected for evaluation. Subsequently, the output of each frame provided by the algorithm was compared with the previously labeled data, and an average was calculated. Overall averages were then obtained to assess the algorithm’s accuracy and execution time. Finally, the best algorithm was chosen for optimization using a genetic algorithm, and any improvements in the results were verified. CSRT was the algorithm that obtained the best result and after optimization with the genetic algorithm, an improvement of 20% in its accuracy was obtained.