'Get Dressed!': Fudan Professor's Warning on Facial Recognition Goes Viral

Caption: A temporary ID card in China, printed with a user's half-naked photo, which he accidentally captured during an online facial recognition process.

A trending topic warning "Never forget to wear clothes during face recognition" has gone viral on Chinese social media recently, startling numerous netizens who rushed to share regrets about their past careless habits in the comment sections.

Many users belatedly realized they had completed facial verification while in bed, on the toilet, or shirtless.

The widespread discussion stems from a resurfaced popular science video featuring Zhang Junping, a professor from the School of Computer Science and Technology at Fudan University. In the clip, originally posted in 2021, Professor Zhang explains that during facial recognition, the system uploads not just the area within the circular frame displayed on the screen, but the entire field of view captured by the camera.

Caption: A netizen said the photo was taken while brushing her teeth.

"You absolutely must have your clothes on," he emphasized in the video. "The camera does not only see the content within the circle. It actually captures everything. That's why you shouldn't do facial recognition while bathing."

Professor Zhang clarified that the "circle" on the screen acts as a "mask" — a visual guide to help users align their faces — rather than a boundary for the camera's capture range. The actual footage recorded extends far beyond this on-screen guide.