Fig. 12

Horizontal transects through the center of the synthetic UMN logo results for scenario 3. Shown at left are the TNT-NN solution and known solution and at right is the difference thereof. Without additional regularization, least-squares methods act as low-pass filters which produce solutions that are naturally smooth. This can manifest as a “spreading” of the solution in space as seen at the right. This behavior does not allow the least-squares solution to fully capture the sharp interfaces in the known solution