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FK 3D PostStack applies a frequency-wavenumber (F-K) filter to a 3D post-stack seismic volume to attenuate coherent noise such as acquisition footprint, linear interference, and spatially-aliased noise. The input gather must be a 3D post-stack volume arranged as a regular inline-by-crossline grid of traces. The module computes the 3D F-K spectrum, displays it interactively in separate inline and crossline panels, and applies a user-defined polygon mute drawn directly on the spectrum to pass or reject energy within the picked region.
The filter operates in two modes. In 3D mode, a full 3D Fourier transform (inline, crossline, and time) is performed, the pick polygon is applied as a mute in the 3D F-K-x/K-y volume, and the data are inverse-transformed back to the time domain. In Pseudo-3D mode, the filter is applied independently to each inline slice of the volume using a 2D F-K transform, which is faster and uses less memory but does not fully exploit the 3D nature of the noise. This module is marked as deprecated; use it for legacy workflows where 3D F-K filtering is required on post-stack data.
Connect the 3D post-stack seismic gather here. The gather must contain exactly InlineCount times CrosslineCount traces arranged in a regular rectangular grid (one trace per bin). When the Calculate Bin Grid option is enabled, the module reads the inline and crossline coordinates from the trace headers and automatically determines the grid layout. If the total trace count does not match the product of the declared inline and crossline counts, the module will report an error and will not produce output.
This item stores the interactive F-K mute polygon that defines the noise rejection zone in the frequency-wavenumber domain. It is created and updated automatically within the module as you pick points on the displayed F-K spectrum. The picking item can be saved to and loaded from a .corr file using the Custom Actions below, allowing you to reuse a mute polygon across multiple datasets or processing iterations. If no picking has been done yet, connecting input data and viewing the F-K spectrum panel is the first step.
Default: enabled (true). When enabled, the module automatically reads the inline/crossline header coordinates from the input gather to determine the grid dimensions (number of inlines, number of crosslines) and the spatial sampling intervals. The calculated values are reported in the read-only output fields at the bottom of the parameter panel. Leave this option enabled for standard 3D datasets where geometry is correctly stored in trace headers. Disable it only if you need to override the grid parameters manually, for example when working with data that have incorrect or missing geometry headers.
Default: 10. The number of inline lines in the input 3D volume. This parameter is active only when Calculate Bin Grid is disabled. The value must be set so that InlineCount multiplied by CrosslineCount equals the total number of traces in the input gather. Setting this incorrectly will prevent execution. When Calculate Bin Grid is enabled, this parameter is ignored and the count is determined automatically.
Default: 460. The number of crossline traces in the input 3D volume. This parameter is active only when Calculate Bin Grid is disabled. Together with InlineCount, it defines the spatial dimensions of the data patch on which the 3D Fourier transform is computed. When Calculate Bin Grid is enabled, this parameter is ignored and the count is determined automatically from trace headers.
Default: 30 m. The physical distance in metres between adjacent inline lines. This value is used to compute the inline wavenumber axis of the F-K spectrum. Accurate spatial sampling values are critical for correct wavenumber scaling: if the step is set larger than the true value the wavenumber axis will be compressed, and vice versa. This parameter is active only when Calculate Bin Grid is disabled.
Default: 30 m. The physical distance in metres between adjacent crossline traces. This value is used to compute the crossline wavenumber axis of the F-K spectrum. As with Step Between Inlines, accuracy is important for correct F-K domain representation. This parameter is active only when Calculate Bin Grid is disabled.
Default: Mute Inside. Controls which part of the F-K spectrum is zeroed (muted) relative to the picked polygon boundary. Mute Inside zeros the energy inside the polygon — use this when the polygon encloses the noise zone (for example, a low-frequency high-wavenumber interference band). Mute Outside zeros all energy outside the polygon — use this when the polygon encloses the signal passband and you want to suppress everything else. A cosine taper controlled by the Taper parameter is applied at the polygon boundary to avoid Gibbs artefacts.
Default: 3D. Selects between two FK filtering strategies. 3D performs a full 3D Fourier transform across all inlines, crosslines, and time samples simultaneously, producing a true 3D F-Kx-Ky spectrum. The mute is applied in this full 3D domain before the inverse transform. This mode gives the most accurate noise attenuation but requires more memory proportional to the volume size. Pseudo3d applies independent 2D F-K transforms slice by slice along inlines. It is faster and uses less memory, and is appropriate when the dominant noise exhibits strong linear moveout along inlines that can be isolated in the inline F-K plane.
Default: 0.1. A fractional transition width applied at the boundary of the F-K mute polygon to produce a smooth roll-off instead of a hard cut. A value of 0.1 means a 10% cosine taper is applied on both sides of the mute boundary. Larger values produce a smoother but wider transition zone, which reduces ringing artefacts while slightly compromising the sharpness of noise removal. A value of 0 produces a hard (brick-wall) mute, which typically introduces high-amplitude edge artefacts in the output. Values between 0.05 and 0.2 are recommended for most datasets.
The F-K filtered 3D post-stack gather in the time domain. The output has the same dimensions, sample interval, and header values as the input gather. Energy within (or outside, depending on Mute mode) the user-picked polygon has been attenuated. The output is only produced when a valid picking polygon is present in the G3DFKPickingItem. If no picks have been made, no output gather is produced.
Removes all currently picked points from the F-K polygon stored in the G3DFKPickingItem. The module will ask for confirmation before deleting. Use this action when you want to start a fresh mute design from scratch without reloading the module.
Opens a file selection dialog to load a previously saved F-K mute polygon from a .corr file. The loaded polygon replaces any existing picks in the G3DFKPickingItem. This allows you to reuse a carefully designed mute polygon on a different dataset or to restore a picking session from a saved state.
Opens a file save dialog to write the current F-K mute polygon to a .corr file. Save the picking after completing your interactive mute design so that it can be reloaded later or shared with colleagues. The file will not be saved if no picking points are present.
The module displays the computed F-K spectrum in two interactive vista panels: one for the inline direction (GVistaFKSpectrumInline) and one for the crossline direction (GVistaFKSpectrumCrossline). Both panels show wavenumber on the horizontal axis and frequency on the vertical axis. The muted spectrum is shown in the GVistaFKSpectrumMute panel after execution.
To define the mute polygon, click directly on the displayed F-K spectrum panel. Left-click adds a new pick point at the clicked frequency-wavenumber location. Left-click and drag moves the nearest selected point. Right-click deletes the nearest pick point. The interpolated polygon boundary (the Curve overlay) is updated in real time as you add or adjust points. Once the polygon is closed around the noise zone, execute the module to apply the filter and view the result in the output gather.