Abstract: |
The threat of climate catastrophe is endangering the integrity of habitats such as forests on our planet. In current forecasts by the Intergovernmental Panel on Climate Change, the habitats on our planet will become even more endangered in the coming years. Intact ecosystems such as forests, however, are the basis of our existence in a complex interplay of countless species given by the biodiversity of these systems. If individual species from these interactions are lost or become prevalent, ecosystems affected by this, threaten to become unbalanced. A crucial aspect to preserve this balance is the preservation and promotion of biodiversity. This requires the monitoring of population levels, for example in the form of area-wide observation of wildlife.
However, safeguarding biodiversity can only be done with the help of accurate surveying techniques, such as counting and analyzing animal populations. This process of population monitoring is needed to detect changes in numbers as well as inter-/intragroup distributions within different species. Such changes represent an indicator of a stable population. Conversely, overpopulation (e.g., invasive species) or underpopulation (e.g., due to disease, loss of habitat, ...) can be identified, which need to be addressed by appropriate means e.g., to protect endangered species or to control the spread of invasive species.
Current methods (e.g., camera traps) use random sampling to estimate the population and density. However, such methods are unsuitable for large-scale areas. In contrast, camera-based observation using uncrewed aerial vehicles (UAV) can be used over large areas, but in forested areas, area-wide observation and counting of wildlife are very limited due to dense vegetation. Accounting for this obscuring forest cover is possible, for the first time, using a new technique called airborne light-field sampling (ALFS), which allows uncovering the forest floor (e.g., wildlife). ALFS is based on light-field technology, in which a RGB and/or thermal video/image sequence of a flyover is combined with position data and an elevation model of the terrain. Unfortunately, ALFS is highly dependent on a static scenario without or with only little movement. For the use case of wild-life monitoring, this can be an issue, as animals may react to the presence of UAVs and may engage in escape behavior. Therefore, the population monitoring should be carried out in a two-folded manner: using integral images (created with ALFS) and geo-referenced video sequences. |