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The Recon module attenuates multiple reflections in seismic gathers by identifying and suppressing energy with anomalous apparent velocity. The algorithm applies a sliding 2D window transform into the frequency-wavenumber (F-K) domain and targets either low-velocity energy (ground roll, surface waves, and water-bottom multiples) or high-velocity energy (interbed multiples with steeply dipping move-out). The difference between the input gather and the reconstructed primary-only gather is output as the multiple model.
Processing is performed in overlapping spatial windows (1-trace overlap) and time windows (1-sample overlap) so that the output is seamlessly merged across window boundaries. An optional AGC pre-conditioning step can be applied before the F-K filtering and is reversed afterwards so that the output amplitudes are preserved relative to the input.
The seismic data container connecting to the input dataset. The module works on pre-stack gathers sorted by CMP/offset before multiple attenuation.
The input seismic gather to be filtered. Connect to the output gather of the preceding module in the workflow. The module outputs both a primary-only gather and a multiple-model gather.
The number of adjacent traces included in each spatial F-K window. A larger window provides better wavenumber resolution and more effective separation of signal from noise in the F-K domain, but may smear laterally variable features. The windows overlap by one trace. Default: 10 traces.
The number of time samples included in each temporal F-K window. Larger values improve frequency resolution in the transform domain but increase the risk of mixing events with different apparent velocities. The windows overlap by one sample. Default: 10 samples.
Controls which energy is attenuated. Up mode attenuates high-apparent-velocity energy (interbed multiples that appear nearly flat on gathers after NMO, or steep-dip noise). Down mode attenuates low-apparent-velocity energy such as ground roll, guided waves, and water-bottom multiples that have residual move-out after NMO. Default: Up.
When enabled, a temporary AGC (Automatic Gain Control) is applied to the gather before the F-K velocity filter to equalize amplitude levels across the record. After the filter is applied, the AGC is reversed by multiplying the output by the original AGC gain function. This improves the detection of weak multiples masked by amplitude decay. Default: enabled.
The length of the time window (in seconds) over which the removable AGC gain is computed. Shorter windows produce a more aggressive amplitude equalization; longer windows preserve the relative amplitude trend better. Only active when Use Removable AGC Filter is enabled. Default: 0.5 s.