A method of extracting image features from objects on a plane within video images; detecting the objects from a relative position on the plane by comparing the extracted image features with sample image features; and generating object identification data identifying the objects on the plane. The method includes generating a 3D model of the plane and logging object identification data and object path data, the object path data including a time history of object position on the 3D model and a path of the objects within the video images. The method also includes detecting an occlusion event indicating whether object features are occluded; associating object identification data with object path data for objects in the occlusion event; identifying one of the objects involved in the occlusion event by comparing the objects image features and the sample image features; and updating the path data after the identification.