A computer-implemented method is provided for identifying objects in an image. The method includes: capturing a series of images of a scene using a camera; receiving a topographical map for the scene that defines distances between objects in the scene; determining distances between objects in the scene from a given image; approximating identities of objects in the given image by comparing the distances between objects as determined from the given image in relation to the distances between objects from the map. The identities of objects can be re-estimated using features of the objects extracted from the other images.