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This module is deprecated. It is retained for legacy workflow compatibility.
The Residual DVA (Dip Velocity Analysis) module estimates a residual velocity correction field from a set of DVA entropy gathers computed at multiple velocity scale factors. For each trace and time sample, it identifies the velocity factor that produces maximum entropy (best focusing), then uses kriging interpolation to create a smooth velocity correction map. The output consists of three attribute gathers: the optimal velocity factor map, the entropy value map, and a focusedness ratio map.
This module is used after migration to detect areas where the velocity model needs correction. The output velocity factor gather guides updates to the velocity model to improve migration focus.
A collection of velocity scale factors (e.g., 0.9, 0.95, 1.0, 1.05, 1.1) corresponding to each DVA entropy gather in the DVACollection. The number of entries must match the number of DVA gathers. Each factor represents the ratio of the test velocity to the reference migration velocity.
A collection of DVA entropy gathers, each computed at a different velocity scale factor. These gathers are produced by the DVA module and represent the focusedness of migrated energy as a function of velocity perturbation. All gathers must have identical dimensions (same number of traces and samples).
The number of neighbouring control points used in the kriging interpolation to spatially smooth the velocity correction field. Higher values produce a smoother output map at the cost of computation time. Default: 5.
The minimum focusedness ratio required for a sample to be considered a reliable velocity correction point. Samples below this threshold are excluded from the kriging interpolation. Setting a higher threshold keeps only the most reliable picks, resulting in a sparser but more confident velocity correction map. Default: 0.0 (all samples included).