31 lines
1.2 KiB
Markdown
31 lines
1.2 KiB
Markdown
# FFT 2D
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Compute the 2D FFT with optional windowing and mean/plane subtraction. Outputs log magnitude, magnitude, phase, and PSDF as separate channels. Equivalent to gwy_data_field_2dfft / gwy_data_field_2dpsdf.
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## Inputs
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| Name | Type | Required | Description |
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|------|------|----------|-------------|
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| field | DATA_FIELD | Yes | Input spatial-domain field |
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## Outputs
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| Name | Type | Description |
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|------|------|-------------|
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| log_magnitude | DATA_FIELD | log(1 + |F|) of the 2D FFT, centered on DC |
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| magnitude | DATA_FIELD | |F| of the 2D FFT, centered on DC |
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| phase | DATA_FIELD | Phase angle of the 2D FFT in radians, centered on DC |
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| psdf | DATA_FIELD | 2D power spectral density function |
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## Controls
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| Name | Type | Default | Description |
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|------|------|---------|-------------|
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| windowing | dropdown | hann | Window function applied before FFT: hann, hamming, blackman, or none |
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| level | dropdown | mean | Pre-processing: subtract mean, subtract plane, or none |
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## Notes
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- Output fields are in the frequency domain; physical units on axes are spatial frequency (1/m).
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- Phase output uses the raw FFT phase and is sensitive to field origin; it is most useful when paired with the Inverse 2D FFT node.
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