Drawing on long years at the easel
While computers are more efficient than people at storing information and retrieving it quickly, the human brain’s primary strength lies in using the imagination to fill in the blanks when information is missing.
That’s why police departments still need people such as Lin Yuhui, an artist who can draw an accurate sketch of a suspect even when security cameras fail to capture a clear image.
Lin’s skill lies in identifying clues that enable him to produce an almost faithful likeness, either from blurred photos or camera surveillance footage that shows just 25 percent of a person’s face.
“As long as incomplete or blurred photos contain a certain amount of information about features such as the eyes, chin or nose, my experience allows me to work out the rest for myself,” he said.
Lin has sketched about 70,000 faces, mainly people he has observed in public places such as railway stations.
The information he garnered enabled him to sort them into eight categories and create a “database” of typical Chinese faces.
“In the past when there was no camera surveillance, most of the information relating to a suspect’s image was provided by victims of crime, which provided very vague and sometimes inaccurate descriptions,” he said.
As a countermeasure, Lin shows victims his hand-painted database in the hope of jogging their memories.
His office at the Public Security Department in Shandong province is always crowded with police officers from across China looking for guidance.
Lin also uses facial features that remain relatively unchanged over time to create portraits of missing children.
“Some parents are searching for their children with photos taken five or six years ago. Because children grow quickly, those old pictures may not help the parents to find the child, so I draw sketches of the child at different ages, which is a better way of helping,” he said.
Mei Lin, direc tor of the Cyber Physical System R&D Center at the Ministr y of Public Security ’s T hird Research Institute, said departments t hat use facialrecognition technology need to cooperate with experienced experts such as Lin to improve the quality of their work.
“We are considering working with police artists to see whether it is possible to use their experience of recovering facial images to improve our computers’ i mageprocessing capacities,” he said.