Fugro-LCT Software© > Grid Signal Analysis
Frequency Domain Grid Filtering with GRDFFT©
A frequency-domain interactive grid enhancement program that:
- Applies a variety of standard and enhanced frequency-domain filters
- Computes upward and downward continuation
- Computes vertical derivatives and integrals
- Shows reduction to pole with low-latitude stabilization
GRDFFT is an interactive frequency-domain grid enhancement program. Users can enhance grid data using a diverse suite of standard and advanced wavenumber domain filters.
Filters may be cascaded without limit. Interpretation of data is easy with GRDFFT's rapid computation and visualization of grid enhancement algorithms.
GRDFFT shows multiple and simultaneous views of the grid data including the original grid, the filtered grid, 3D views, the power spectrum and radial-averaged power spectrum. In addition to its important use for potential field data, users can apply GRDFFT to seismic, topographic, and other grid datasets.
Filters include:
- Low, high and band pass
- Vertical / Horizontal derivative or integrals
- RTP for high and low latitudes
- Differential RTP for large areas
- Pseudo gravity and magnetic transformations
- Wiener noise removal
- Tilt Angle Filter
- Magnetic Component Calculation
- Multiple import/export grid file type options
- Upward and downward continuation from and to arbitrary surfaces
Spatial Domain Grid Filtering with GRDSDT©
A space-domain interactive grid enhancement program that:
- Applies a variety of linear and non-linear space-domain filters
- Computes vertical derivatives and integrals
- Fast computations with more benign edge effects than frequency-domain filters
In the past, the space domain filtering was very slow compared with frequency domain filtering. As computers have become very fast and affordable, spatial domain filtering is becoming more feasible. Fugro Gravity & Magnetic Services new module, GRDSDT, provides the explorationist with a rich set of filters to bring out subtle features in gridded datasets. Compared to frequency domain filtering, spatial domain filtering is more robust to noise, suffers much weaker edge effect, and can perform nonlinear transformations.
Filters include:
- Smoothing and Restoration
- Polynomial fitting
- Automatic Gain Control
- Derivatives and Sharpening
- Coherence
- Edge-enhancing smoothing
- Curvature attributes
- Easy import of a variety of grid formats, such as GXF, GMT and USGS grids
- Multiple import/export grid file type options
Application of horizontal gradient transformation followed by coherence filter to the gravity response of a shallowly-buried cube. The black square shows the position of the cube on the computation plane. The coherence of the HGA of the gravity delineates cube boundaries better than the HGA.
