Enhancing UAV images to improve the observation of submerged whales using a water column correction method.

Insights into the use of an unmanned aerial vehicle (UAV) to investigate the behavior of humpback whales (Megaptera novaeangliae) in Vava'u, Kingdom of Tonga. For whales on or just below the surface, the red/green and red/blue depth-invariant band pairs were the most effective band pair combination for enhancing contrast between the whale and surrounding waters, both visually (Figure 3A and C) and resulting in the highest anomaly values (Table 1). The UAV was launched to an initial altitude of 55 m to provide sufficient sensor field of view for whale identification and lowered to >=25 m once whale(s) were visible on the controller screen. [Extracted from the article]