Figure 1. Stratal slices from a horizon picked close to t=1200 ms through (a) Sobel filter similarity, and (b) energy ratio coherence volumes. Although both "coherence" algorithms used the same structurally-oriented filtered data volume as input and the same 5-trace by ±10 ms analysis window, these two images are quite different, with the Sobel filter similarity showing more stratigraphic features and the energy ratio coherence providing sharper fault images.