Indexing open imagery to create tools to fight sex trafficking

Images are important to fighting sex trafficking because they are: (a) used to advertise for sex services, (b) shared among criminal networks, and (c) connect a person in an image to the place where the image was taken. This work explores the ability to link images to indoor places in order to support the investigation and prosecution of criminal activity. We propose a framework which includes a database of open-source information available on the Internet, a crowd-sourcing approach to gathering additional images, and two baseline matching approaches. We concentrate on spatio-temporal indexing of hotel rooms, and to date have an index of more than 1.5 million geo-coded images. Our smart-phone app collects contextual information and metadata along-side images. On a test that included a database of 1800 images from 200 different hotels in St. Loouis, the correct hotel that matched a query images was found in the top 10 responses two-thirds of the time. We conclude with an analysis ocitehe successes and limitations of our data set, our matching process, and suggestions for future research.