1. A method comprising: filtering 3D lung image data, the 3D lung image data comprising a plurality of voxels and using at least one of a filter based on both planar structures and vessel suppression, a filter based on curvature computations, and a filter based on local gradient magnitude and direction comparisons; for each voxel of said plurality of voxels, calculating a score representing the likelihood of the voxel being a fissure using said at least one of a filter based on both planar structures and vessel suppression, a filter based on curvature computations, and a filter based on local gradient magnitude and direction comparisons; and identifying lobar fissures in the 3D lung image data based on the filtered 3D lung image data resulting from said filtering step.