Figure is a generalization of Figure . The red (darker in gray scale) dots are the same as in Figure , and represent the mapping into angle domain with degrees, and degrees. The green (lighter in gray scale) is the mapping when the azimuthal range is broader close to normal incidence, that is with degrees, and degrees, and p=3. Notice that the integration domain represented by the green dots (lighter in gray scale) does not shrink close to the origin, as the original integration domain does.
Figure shows the effect of the variable azimuthal range on the synthetic data set. Figure b shows the same ADCIG as in Figure b. The azimuthal range was constant over ;that is degrees, and degrees. Figure a shows the ADCIG extracted at the same location as the one in Figure b, but obtained with variable azimuthal range. The parameters were degrees, degrees, degrees, degrees, and p=3. The reduction in the azimuthal range attenuates the numerical noise in the image. In particular, it attenuates the ``frowning'' artifacts that, as I discussed in the previous section, are related to the narrow azimuthal coverage of the data.
Figure shows a depth slice extracted from the image at the same depth as the slices shown in Figures -, but with the variable azimuthal range defined by the parameters listed above. The comparison of Figure with Figure demonstrates that the window defined using the relationships (1) and (2) preserves the coherent energy of the event, while removing noise.
Figure 9 Graphical representation of the effects of the variable azimuthal range on the mapping from the offset wavenumber plane into the plane. The green (lighter in gray scale) dots correspond to the mapping with variable azimuthal range.
Figure 10 ADCIGs for a synthetic data set. Left: Image obtained after application of both the angular dependent weighting and the variable azimuthal range. Right: Image obtained after application of the angular dependent weighting.
Figure 11 Depth slice taken at the same depth as the slice shown in Figure (z=1,1140 meters), after application of both the angular dependent weighting and the variable azimuthal range.