Hybrid corner and edge-based tracking

A method of detecting an initial pose of an object in an image frame, the method comprising:

• acquiring, from a camera, an image frame representing an object in a real scene;
• detecting, from the image frame, image first features using a first feature detection algorithm;
• retrieving, from one or more memories, data containing (a) a preceding pose of the object, (b) preceding image first features detected in a preceding image frame prior to the image frame and corresponding to the preceding pose of the object, and (c) first 3D points corresponding to the preceding image first features;
• matching the image first features and the preceding image first features to establish first correspondences between the image first features and the first 3D points;
• deriving a candidate pose of the object corresponding to the image frame based on the preceding pose of the object and the first correspondences;
• deriving (a) candidate pose second features using the candidate pose and (b) second 3D points corresponding to the candidate pose second features;
• detecting, from the image frame, image second features using a second feature detection algorithm;
• matching the image second features and the candidate pose second features to establish second correspondences between the image second features and the second 3D points;
• and
• deriving a pose of the object in the image frame based on (a) the candidate pose, (b) the first correspondences, and (c) the second correspondences.

A head-mounted display device comprising:

• a camera;
• one or more memories;
• a display device;
• and
• a processor configured by instructions stored in the one or more memories to perform a method comprising:
• acquiring, from the camera, an image frame representing an object in a real scene;
• detecting, from the image frame, image first features using a first feature detection algorithm;
• retrieving, from the one or more memories, data containing (a) a preceding pose of the object, (b) preceding image first features detected in a preceding image frame prior to the image frame and corresponding to the preceding pose of the object, and (c) first 3D points corresponding to the preceding image first features;
• matching the image first features and the preceding image first features to establish first correspondences between the image first features and the first 3D points;
• deriving a candidate pose of the object corresponding to the image frame based on the preceding pose of the object and the first correspondences;
• deriving (a) candidate pose second features using the candidate pose and (b) second 3D points corresponding to the candidate pose second features;
• detecting, from the image frame, image second features using a second feature detection algorithm;
• matching the image second features and the candidate pose second features to establish second correspondences between the image second features and the second 3D points;
• deriving a pose of the object in the image frame based on (a) the candidate pose, (b) the first correspondences, and (c) the second correspondences;
• and
• display, with the display device, a display image, at least one of the position at which the display image is displayed and the content of the display image being based at least in part on the derived pose of the object.