A drone spied a missing elderly woman who suffers from dementia after searchers on foot were defeated by rough terrain, authorities said.

The Randolph County Sheriff's Office in North Carolina launched the small, remote-controlled device equipped with a camera and flew it over a 40-acre field near the woman's home, then over a desiccated cornfield.

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There, in a sea of waving brown stalks, was a blur of purple. The department's drone operator dropped the camera until it captured the gray-haired, 81-year-old woman sitting in the dirt.

As the drone approached, she looked up and pulled the hood of her purple jacket over her head. 

Deputies approached, kneeling in front of her and radioing colleagues that she was fine and not injured.

The woman's husband reported her missing at about 11:30 a.m. Sunday. Family members had looked around the couple's property, but couldn't find her.

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Deputies and K-9 units searched the rural area on foot, but were slowed down by the size of surrounding properties and rough terrain.

Within minutes of deploying the department's 6-week-old drone, the lost woman was spotted.

"The family expressed their gratitude for the quick response," Sheriff Robert Graves posted on the office's Facebook page. "I am very proud of all of our team."