Scientists unlock secrets of bird-brained vision

Researchers at the University of Queensland’s Brain Institute (QBI; St Lucia, Queensland) have unlocked the secret of how birds avoid collisions as they soar, swoop, dive, glide, and engage in other aeronautic maneuvers.

According to lead researcher Partha Bhagavatula, PhD, it had been suggested that birds detect and avoid obstacles and control landing maneuvers by using cues derived from the motion of images they see during flight.

To investigate whether that was the case, during their research experiments the team filmed birds' trajectories during flight in a corridor whose walls were decorated with various combinations of thick black horizontal and vertical stripes.

They found that birds flew down the center of the corridor when the optical cues were balanced (with identical, vertical stripes on either side of the corridor) but more closely toward one wall or another when these cues were unbalanced (such as when one wall was lined with horizontal stripes and the other with vertical stripes).

The birds also flew faster when the tunnels were lined with horizontal stripes (rather than vertical stripes), indicating that they were using the optical cues to regulate their flight speed.

According to Queensland’s Brain Institute Professor Srinivasan, the findings have important implications for robotics. Specifically, the research could teach scientists a lot about designing vision systems for guiding autonomous aerial vehicles (also known as unmanned aerial vehicles, or UAVs) through densely cluttered environments.

The researchers documented their results in a recent paper -- "Optic Flow Cues Guide Flight in Birds" -- that was published in Current Biology.

-- By Dave Wilson, Senior Editor, Vision Systems Design