Figure 1

Challenges of detecting elephants in their natural habitat. (a) Two highly occluded elephants. This example shows that shape is not a good indicator for elephant detection. (b) A group of elephants. Due to bad lighting conditions, the elephant labeled with an arrow has a very low contrast and is thus difficult to detect, especially in front of the background (plants) which is dark as well. (c) Elephants at a water hole. The encircled areas show regions on the ground and on the elephant’s skin which have similar color and are thus difficult to distinguish. (d) Elephants on a wet trail. The elephant’s skin is partly covered by mud from the ground.