Robot video search for missing 'woody woodpecker'

Alex Zaharov-Reutt
Monday, 19 February 2007 15:22

Science - Biology

The challenge, they say, is for the software to automatically recognize when animals are present. "Passive infrared (PIR) motion sensors are sometimes used in wildlife research," said Goldberg, who has pioneered networked teleoperation systems for more than a decade. "The problem is that PIR sensors look for heat and are not triggered by birds flying overhead. So we're developing a robotic system that analyzes high resolution video in real time."

In February 2006, the Cornell researchers took Goldberg and Song out to the Cache River National Wildlife Refuge to scout out potential locations for placing the remote cameras. Because no one knows exactly where the bird might appear, the cameras must cover a relatively wide swath of sky.

They settled upon a power line that cuts through the bayou and provides a 50-foot-wide clearing unobstructed by trees.

"It's a natural bottleneck in the forest, and birds passing through that corridor are relatively easy to spot because they expose themselves," said Ron Rohrbaugh, project director at the Cornell Lab of Ornithology. "At this location, we should have the highest probability of capturing an image of the ivory-billed woodpecker."

With the generous help of the Arkansas Electric Cooperative, a 69 kilovolt transformer was erected for the project that provides both a power source and a post to mount the equipment. The researchers decided against solar and battery cells because they would not provide a reliable enough power source.

The two cameras - one pointing east and the other west - are connected to a computer that processes the data. Waterproof gear helps protect the equipment from the elements, including rain and wind, and even from occasional bird droppings.

The researchers created software that keeps video files only when potential "bird flight" movement is sensed.

The software is based on new algorithms that can handle the unpredictable conditions of a natural environment, filtering out false readings from clouds, water reflections and falling leaves. "The program knows, for instance, that the ivory-billed woodpecker flies 20 to 40 miles per hour, so anything outside that range is deleted," said Song, who worked with Ni Qin, a computer science Ph.D. student at Texas A&M, on the software.

"The high-resolution camera we have shoots at 22 frames per second, with approximately 2 to 3 megapixels per frame," said Song. "That's a huge amount of data that must be managed."

Collecting the video data involves a decidedly low-tech approach: Luneau takes a boat out to the site every two weeks to change the disk.

Not only is Luneau skilled with computer equipment, he is an avid bird-watcher and a leading member of the ivory-billed woodpecker search team in Arkansas. He does an initial screening of the images from the hard drive, and then sends the data to researchers at Cornell, Texas A&M and UC Berkeley.

And what if a high-quality image of the ivory-billed woodpecker is captured? "If something really interesting is in the frame, Cornell makes the call (on the identity of the bird)," said Song.

Rohrbaugh pointed out the benefits of using an autonomous camera. "There are other ways of searching for the ivory-billed woodpecker, but those ways usually involve a human positioned in the forest for a very long time," he said. "Humans are expensive, and they're not always alert, and their simple presence is a disturbance to the environment, even when they're camouflaged and sitting quietly. Remote systems that can serve as our eyes and ears are a big advantage."

Song also noted that using the camera extends the search season to the entire year.

"Usually people do this type of bird-watching in the winter because there are fewer leaves, making it easier to spot the woodpecker," Song said. "Also, in the summer, the temperature is hot, it's swampy, and there are mosquitoes and snakes to deal with. Our system can run the whole year, and it is not bothered by mosquitoes."

The researchers are continuing to fine tune the system and algorithms while combing carefully through each new set of video that is collected.

"I'm a person who's been in the outdoors all my life, and I'm trained as a wildlife biologist," said Rohrbaugh. "Certainly going into this I had a lot of skepticism about the usefulness of this robotic camera. But now there's hope that by using this camera, we can get a hi-res image that is an indisputable piece of evidence that the ivory-billed woodpecker is living in Arkansas."

However, the researchers also acknowledge the possibility that the robotic cameras may never capture definitive footage of the famed woodpecker.

"I'm hopeful, but not overconfident," Goldberg said. "We're willing to run this camera for years, and we're prepared to accept it if we never see the bird. But if this persistent robot out on the bayou manages to capture verifiable high-resolution images of the legendary ivory-bill, it would be a major discovery for scientists, for conservationists and for more than 45 million American bird-watchers."