Degree of Polarization (dop_fp) — PolSARtools 0.11 documentation

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# Degree of Polarization (`dop_fp`)

polsartools.dop_fp(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)

  Calculate Barakat Degree of Polarization from full-pol SAR coherency/covariance matrix.

  This function computes the Barakat Degree of Polarization (DoP) from full-polarimetric SAR data using either the coherency (T3) or covariance (C3) matrix. The Barakat DoP provides a generalized measure of the polarization state for partially polarized waves in full-pol SAR systems.

  Examples

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

      >>> # Advanced usage with custom parameters
      >>> dop_fp(
      ...     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 C3 or T3 matrix files.

    - win (int, default=1) – Size of the spatial averaging window. Larger windows improve DoP estimation accuracy 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 a Cloud Optimized GeoTIFF (COG) 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, applies LZW compression to the output GeoTIFF files.

    - 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 one output file to disk: - ‘dop_fp.tif’ or ‘dop_fp.bin’: Barakat Degree of Polarization image

  Return type:

    None

\[\text{DOP}_{fp}=\sqrt{1-\frac{27\times\text{det([T3])}}{\text{(Trace[T3])}^3}}\]

Further details on the Barakat Degree of polarization can be found in [[10]](#10)