Motion Stills AR Stickers Done With Instant Motion Tracking

Google's Motion Stills started out as an ironically iOS-only app that employed otherwise geeky computer vision and algorithms to produce impressive and stabilized video clips. Motion Stills finally arrived on Android last year, but hasn't exactly gotten much love since then. That changes today, with Google rolling out a new feature that plays to the company's new-found love for augmented reality. Yes, AR stickers have arrived on Motion Stills, and it's actually a bit more complicated behind the scenes than you might expect from such a whimsical feature.

This isn't simply a matter of having a 2D smiley or sticker that stays in place no matter where you turn. It involves placing 3D virtual objects in the real-world that seem to know exactly where they are placed and move and resize just like real-world objects do.

Unsurprisingly, there's a lot of math and theory involved, and Google is also unsurprisingly very excited to share it with anyone willing to listen. Motion Stills uses the phone's accelerometer to determine the device's orientation in relation to the ground, which it then uses to determine how to place the 3D object. But since the 3D object has to move and resize accordingly, simply knowing where to place it isn't enough. That's where Google's Instant Motion Tracking kicks in.

In a nutshell, Instant Motion Tracking estimates an object's movement (translation) separately from its rotation. This allows the app to scale the object up or down as the camera gets closer and rotate the image depending on the phone's gyroscope. This is similar to the Motion Text effect that Google introduced in the iOS version of Motion Stills.

Of course, all of this is invisible to the end user, who simply has to tap in the camera's viewfinder to place such a 3D AR sticker. As with any Motion Stills clip, you can record it as a video or GIF to show off to others. In addition to the new AR mode, the updated Android app also features a cleaner UI to make using it easier and faster.