Motion camouflage

Principle of motion camouflage. An attacker A flies towards a target T, choosing its path so that it remains on a line between T and a landscape point P. A thus looms larger as it closes on T, but does not otherwise appear to move

Motion camouflage is a dynamic type of camouflage by which an object can approach a target while appearing to remain stationary from the perspective of the target. The attacking object simply remains on the line between the target and some landmark point, so it seems to stay near the landmark point from the target's perspective. The only visible evidence that the attacker is moving would be its angle and its looming, the change in size as the attacker approaches. First discovered in certain flies, it has been suggested that missiles could use similar techniques to reduce the time available to targets to respond.

Biological examples

The Australian Emperor dragonfly uses motion camouflage to approach rivals

Motion camouflage was discovered by Srinivasan and Davey in 1995 who were studying mating behavior in hoverflies. The male hoverfly appeared to be using the tracking technique to approach prospective mates.

Motion camouflage has also been observed in territorial battles between dragonflies, where males of the Australian Emperor Dragonfly, Hemianax papuensis, were seen to adjust their flight paths to appear stationary to their rivals in "breakneck territorial dogfight[s]". Researchers found that 6 of 15 encounters involved motion camouflage.

External links

• Dragonflies prove clever predators
• Steering laws for motion camouflage
• Octave implementation of 2D Motion Camouflage
• Brisbane Insects: Australian Emperor Dragonfly