A Chinese technology startup has begun selling software that recognizes people by their body shape and how they walk, enabling identification when faces are hidden from cameras.
Already used on the streets of Beijing and Shanghai, "gait recognition" is part of a push to develop artificial-intelligence and data-driven surveillance across China.
Huang Yongzhen, the CEO of Watrix, said its system can identify people from up to 50 meters, which is 165 feet away, even with their backs turned or faces covered.
This can fill a gap in facial recognition, which needs close-up, high-resolution views of a person's face to work.
Chinese police also use facial recognition to identify people in crowds and nab jaywalkers.
Not everyone is comfortable with such surveillance.