When Samsung unveiled the Galaxy S 4 in March, there was a near-inescapable emphasis on face detection features. What we didn't know is just whose technology was making them possible. As it happens, it's not entirely Samsung's -- DigitalOptics has stepped forward to claim some of the responsibility. The California firm recently struck a multi-year licensing deal with Samsung to supply its Face Detection and Face Tracking software, which can detect pupils for interface features (think Smart Stay or Smart Pause) and keep tabs on photo subjects. DigitalOptics hasn't provided the exact details of its involvement in the GS4, let alone a roadmap, but it's safe to presume that Samsung isn't dropping its emphasis on camera-driven software anytime soon.