Smart Child Porn Detection Algorithm Will Help Cops Sift Through Illicit Imagery

Fraunhofer Filter

desCry is a program that automatically searches photos and videos for child-pornographic content, and displays suspicious images on an image viewer.© Fraunhofer IPK

Police who track pedophiles have to do some pretty thankless work once they have their perps — they must sift through large volumes of videos and images to find the illegal ones, and catalog what they've found. Now a new detection algorithm could make their work a little easier, by helping to spot files containing child pornography.

By the time authorities have tracked down and deleted images of child abuse victims, they've already been downloaded, explains a news release from the Fraunhofer Institute for Production Systems and Design Technology IPK in Berlin. And the hoarders of this illicit imagery are pretty good at hiding it, sometimes burying the files in mountains of other unrelated data. Fraunhofer's new pattern-recognition software can sort and organize a computer's contents, and then analyze images and video to search for qualities that would characterize them as child porn.

"Technologies such as facial and skin-tone recognition are combined with contextual and scene analyses to identify suspicious content," said project manager Raul Vicente-Garcia.

The images are displayed as thumbnails in an image viewer, like the one seen above, and suspicious files are singled out. An investigator can click to embiggen each of them to inspect it, and a second click marks the images as evidence, according to Fraunhofer. A human investigator still has to verify the software's findings, but it's much faster than looking through each file individually — on a standard computer, the software can process 10 images per second.

The system is called "desCRY," after a literary English word meaning "to discern" or "to catch sight of."

Porn filters are not a new idea — remember this sonic one, that listens for the telltale sounds of sexual activity? Still, this Fraunhofer one is interesting because it combines still image and video detection, still an evolving field for search programmers. And it focuses on child porn, a particular target for police agencies around the globe.

Researchers led by Bertram Nickolay at Fraunhofer IPK worked with investigators from the State Office of Criminal Investigation in Berlin to develop the system, and this month they are considering using it in field tests. Meanwhile, software giant SAP agreed to help market the technology, Fraunhofer says.