When a child goes missing at a large public event, worried parents and the police would normally search through CCTV footage of the surrounding area. In the future they might try hunting through the photos being taken by smartphone owners instead, using a new system called Theia developed by a team of US researchers.
Privacy concerns aside, searching smartphone photos is a clever idea, but constantly querying someone’s phone sounds like a great way to drain their battery – not a service that many people are likely to sign up for. That’s why Theia is designed to cleverly manage energy usage, while also paying smartphone owners for sharing their photos.
It works like this. People sign up to Theia by downloading a mobile app that can search through photos stored in a folder designated for sharing, while search requests are carried out with a separate piece of software that runs on an ordinary computer. Searchers can select a number of options, such as face and body detection, texture matching, and colour filtering. For example, the system can find pictures of people’s faces against a cloudy sky by combining face detection with a search for cloudy textures and the colour blue.