The Structurally-Oriented Filtering (SOF) process smooths along structural planes as defined by a dip field. It is an effective method of removing incoherent noise and improving continuity of events, without smoothing across dipping planes.
This process requires a dip field to guide the smoothing operation (see Dip Field).
Create SOF process
- In the Control Panel, open the Process tab.
- At the tab header, click the Add icon and select New Process.
- Double-click Structurally-Oriented Filter.
- Type a name for the process and click OK.
Define SOF settings
- In the Details Panel at Dip Volume, select the dip volume that will be used in the SOF process.
- At Input Volume, select the volume that you want to apply the filter. The fields to define more settings for SOF will be available.
- At Half-window distance for smoothing along inline (crosslines), type the value for the inline smoothing radius. A bigger value means more smoothing to be applied in this direction.
- Likewise, type the value for the crossline smoothing radius at Half-window distance for smoothing along crossline (inlines).
- If you have selected a gather volume at Input Volume, you can type the smoothing radius for the gather dimension at Half-window distance for smoothing across gather (m).
- At Percentage to retain when smoothing, type a percentage value to determine whether you want to apply the mean or median-mean smoothing in the process. By default, this is set at "100" which indicates the mean smoothing. The process will apply the median-mean smoothing at a percentage less than 100.
As a result of this process, a new volume is available in the Volume tab.
Tip: To quickly open the output volume, right-click the process item in the Process tab and click Open Child Volume. Vice versa, you can also open the process from the Volume tab directly. To do this, right-click the volume which was created from a process (indicated in italics) and click Open Parent Process.
The following example shows the SOF volume displayed in the IL/CL View:
Example of SOF
The SOF is essentially dip-aware smoothing. The parameters control the number of traces to be combined in the IL and CL directions.
To use a concrete example to demonstrate the filtering technique used by Insight: if the half-window distance for smoothing along the inline and crossline are set to 2 and 3 respectively, then it will:
- Read a 5 crosslines by 7 inlines grid of samples around a given point, following the dip.
- Average those 35 samples together to get a new output sample for that location.
- Repeat for every sample in the volume.
The larger the half-window distances, the more it will tend to emphasize large and strong events, and tend to remove short and stubby reflections and noise.