17. An object/scene recognition method comprising, with one or more mobile computing devices: obtaining two-dimensional image data and three-dimensional image data from one or more image sensors; temporally and spatially aligning the two-dimensional image data and the three-dimensional image data; and recognizing a plurality of visual features in the image data by: recognizing larger-scale objects; recognizing smaller-scale objects by iteratively performing context-free object identification and contextual object identification; and recognizing a complex object comprising a plurality of the smaller-scale objects using a classifier.
17. An object/scene recognition method comprising, with one or more mobile computing devices: obtaining two-dimensional image data and three-dimensional image data from one or more image sensors; temporally and spatially aligning the two-dimensional image data and the three-dimensional image data; and recognizing a plurality of visual features in the image data by: recognizing larger-scale objects; recognizing smaller-scale objects by iteratively performing context-free object identification and contextual object identification; and recognizing a complex object comprising a plurality of the smaller-scale objects using a classifier. 19. The method of claim 17 , comprising executing an invariant three-dimensional feature detection algorithm directly on point cloud data obtained from at least one of the image sensors.