  We propose a method that integrates two widely available data sources,
building footprints from 2D maps and street level images, to derive valuable
information that is generally difficult to acquire -- building heights and
building facade masks in images. Building footprints are elevated in world
coordinates and projected onto images. Building heights are estimated by
scoring projected footprints based on their alignment with building features in
images. Building footprints with estimated heights can be converted to simple
3D building models, which are projected back to images to identify buildings.
In this procedure, accurate camera projections are critical. However, camera
position errors inherited from external sensors commonly exist, which adversely
affect results. We derive a solution to precisely locate cameras on maps using
correspondence between image features and building footprints. Experiments on
real-world datasets show the promise of our method.
