Neumann decomposition (neumann_parm)#

polsartools.neumann_parm(in_dir, win=1, fmt='tif', cog=False, ovr=[2, 4, 8, 16], comp=False, max_workers=None, block_size=(512, 512), progress_callback=None)[source]

Perform Neumann Decomposition for full-pol SAR data.

This function implements the Neumann decomposition for full-polarimetric SAR data, extracting four key parameters: polarization orientation angle (psi), degree of polarization (delta_mod), phase difference (delta_pha), and helicity (tau). This decomposition is particularly useful for characterizing complex scattering mechanisms in urban and natural environments.

Examples

>>> # Basic usage with default parameters
>>> neumann_parm("/path/to/fullpol_data")

>>> # Advanced usage with custom parameters
>>> neumann_parm(
...     in_dir="/path/to/fullpol_data",
...     win=5,
...     fmt="tif",
...     cog=True,
...     block_size=(1024, 1024)
... )
Parameters:

  • in_dir (str) – Path to the input folder containing full-pol T3 or C3 matrix files.

  • win (int, default=1) – Size of the spatial averaging window. Larger windows reduce speckle noise but decrease spatial resolution.

  • fmt ({'tif', 'bin'}, default='tif') – Output file format: - ‘tif’: GeoTIFF format with georeferencing information - ‘bin’: Raw binary format

  • cog (bool, default=False) – If True, creates Cloud Optimized GeoTIFF (COG) outputs with internal tiling and overviews for efficient web access.

  • ovr (list[int], default=[2, 4, 8, 16]) – Overview levels for COG creation. Each number represents the decimation factor for that overview level.

  • comp (bool, default=False) – If True, uses LZW compression for GeoTIFF outputs.

  • max_workers (int | None, default=None) – Maximum number of parallel processing workers. If None, uses CPU count - 1 workers.

  • block_size (tuple[int, int], default=(512, 512)) – Size of processing blocks (rows, cols) for parallel computation. Larger blocks use more memory but may be more efficient.

Returns:

Writes four output files to disk:

  1. Neu_psi: Polarization orientation angle

  2. Neu_delta_mod: Degree of polarization

  3. Neu_delta_pha: Phase difference

  4. Neu_tau: Helicity parameter

Return type:

None

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