Determining coordinate frames in a dynamic environment

A head-mounted display device, comprising:

• a plurality of sensors;
• a see-through display;
• a logic machine;
• and
• a storage machine holding instructions executable by the logic machine to
• obtain a representation of the real-world features in two or more coordinate frames;
• receive sensor data from two or more sensors, a first sensor corresponding to a first coordinate frame and a second sensor corresponding to a second coordinate frame, and one or more of the first sensor and the second sensor being located external to the head-mounted display device;
• distinguish a real-world feature in the first coordinate frame from a real-world feature in the second coordinate frame based upon the sensor data;
• and
• display via the see-through display a virtual object positionally associated with a real world object in a selected coordinate frame.

On a head-mounted display device, a method of tracking real-world features, the method comprising:

• obtaining a representation of real-world features in a coordinate frame using image data from a camera;
• obtaining motion data from two or more inertial measurement units, one or more of the inertial measurement units being external to the head-mounted display device;
• detecting movement of a first real-world feature relative to a second real-world feature based on information from one or more of the image data and the motion data;
• and
• separating the coordinate frame into different coordinate frames including a first coordinate frame and a second coordinate frame, the first real-world feature being associated with the first coordinate frame based upon data from a first inertial measurement unit and the second real-world feature being associated with the second coordinate frame based upon data from a second inertial measurement unit.