In this' patio of heaven ', people are likely to be more sensitive to the sky which is usually ignored, to the sunlight at the top of the wall, as well as to the projection of the flying corridor.

The algorithm first makes a top-down coarse location using the projection analysis of the edge density graph and then makes a bottom-up precise location based on the vertical edge linkage intensity.

The space configuration illustrated in v? H? W three-plane projection drawing (i. e. front view, top view and left view) can generally be determined completely.