Christian Haschek, who lives in Austria, came up with the solution after he discovered an image showing child sex abuse had been uploaded on his image hosting platform Pictshare.
He called the police, who told him to print it out and bring it to them.
However it is illegal to possess images of child abuse, digitally or in print.
“Erm… not what I planned to do,” Mr Haschek said.
Instead he put together a homegrown solution for identifying and removing explicit images.
Mr Haschek used three Raspberry PIs, powering two Intel Movidius sticks, which can be trained to classify images. He also used an open source algorithm for identifying explicit material called NSFW (Not Safe For Work), available free of charge from Yahoo.
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