METHOD AND APPARATUS FOR DEVICE ORIENTATION TRACKING USING A VISUAL GYROSCOPE

A method for tracking device orientation on a portable device is disclosed. The method comprises initializing a device orientation to a sensor orientation, wherein the sensor orientation is based on information from an inertial measurement unit (IMU) sensor. It also comprises initiating visual tracking using a camera on the portable device and capturing a frame. Next, it comprises determining a plurality of visual features in the frame and matching the frame to a keyframe, wherein capture of the keyframe precedes capture of the frame. Subsequently, it comprises computing a rotation amount between the frame and the keyframe. Responsive to a determination that a rotational distance between the frame and the keyframe exceeds a predetermined threshold, promoting the frame to a keyframe status and adding it to a first orientation map and adjusting the frame with all prior captured keyframes.