Dynamic object tracking

A head mounted display that determines and displays movement of an object in an environment, comprising:

• a camera that captures an image stream of the environment, including an earlier image and a later image;
• a processor configured to:
• identify later environment features located in the environment in the later image, earlier environment features located in the environment in the earlier image, and earlier object features located on the object in the earlier image;
• determine a camera movement from the earlier image to the later image using a difference in location between the earlier environment features and the later environment features;
• estimate object features in the later image using the earlier object features and the determined camera movement;
• locate, in the later image, matched object features that are actual object features in the later image at a same location as the estimated object features;
• determine that the object has moved between the earlier image and the later image if a number of matched object features does not exceed a threshold;
• and
• determine that the object has not moved between the earlier image and the later image if the number of matched object features exceeds the threshold;
• and
• a display that displays a notification if the object has moved.

A non-transitory computer readable medium that embodies instructions that cause one or more processors to perform a method comprising:

• acquiring an earlier image and a later image of an environment from an image stream captured by a camera;
• identifying later environment features located in the environment in the later image, earlier environment features located in the environment in the earlier image, and earlier object features located on the object in the earlier image;
• determining a camera movement from the earlier image to the later image using a difference in location between the earlier environment features and the later environment features;
• estimating object features in the later image using the earlier object features and the determined camera movement;
• locating, in the later image, matched object features that are actual object features in the later image at a same location as the estimated object features;
• determining that the object has moved between the earlier image and the later image if a number of matched object features does not exceed a threshold;
• determining that the object has not moved between the earlier image and the later image if the number of matched object features exceeds the threshold;
• and
• instructing a display to displaying a notification if the object has moved.