Figure 5.

(a) Average atlas. (b) Atlas built without frequency domain decomposition. (c) Proposed atlas built with frequency domain construction. (d) An example patch from the average atlas, along with its frequency subband composition examples. For the average atlas, dictionary elements are combined with equal weights. (e) Similar composition example for the patch from the atlas built without frequency domain decomposition. Dictionary elements from respective subjects are combined with unequal weights, although weights on different subbands remain the same. (f) For building the proposed atlas, dictionary elements for different subjects and different subbands are combined with different contributions. See text for details. The patches shown here are enlarged for illustration purpose. [Color figure can be viewed in the online issue, which is available at http://wileyonlinelibrary.com.]