In some implementations, a computer-implemented method of classifying image data includes receiving a plurality of data points corresponding to three-dimensional image data; creating from the plurality of data points a first subset of data points that are above a ground plane in a scene represented by the plurality of data points; identifying a second subset of data points associated with an object in the scene, from the first subset of data points; identifying a plurality of features associated with the second subset of data points and determining a signature for the identified plurality of features; and classifying the second set of data points according to a correspondence between the calculated signature and a reference signature.