##
2-D Bases of the Wavelet Subspaces

These are the basis functions to generate the wavelet
subspaces of the two dimensional L-2 space. The upper
left spans the subspace V, and upper right spans the subspace
Vh, the lower left spans the Vv, while the lower right
spans the Vd. V represents the lower frequency components,
both in vertical and horizontal directions,
Vh represents the horizontal lower but vertically higher
components, Vv represents the vertical lower but horizontally
higher components, while Vd represents the higher
frequency features in both directions.

Maintained by
*Zhaobo Meng*