import os
import numpy as np
from polsartools.utils.proc_utils import process_chunks_parallel
from polsartools.utils.utils import time_it
from polsartools.cprvicpp import process_chunk_cprvicpp
from .cp_infiles import cpc2files
[docs]
@time_it
def cprvi(in_dir, chi=45, psi=0, win=1, fmt="tif", cog=False,
ovr = [2, 4, 8, 16], comp=False,
max_workers=None,block_size=(512, 512),
progress_callback=None, # for QGIS plugin
):
"""Compute compact-pol Radar Vegetation Index (CpRVI) from C2 matrix data.
This function processes compact-polarimetric SAR data to generate the CP-RVI, which
is useful for vegetation monitoring and biomass estimation using compact-pol SAR systems.
The processing is done in parallel blocks for improved performance.
Examples
--------
>>> # Basic usage with default parameters (right circular transmission)
>>> cprvi("/path/to/cp_data")
>>> # Custom parameters for left circular transmission
>>> cprvi(
... in_dir="/path/to/cp_data",
... chi=-45,
... psi=0,
... win=3,
... fmt="tif",
... cog=True
... )
Parameters
----------
in_dir : str
Path to the input folder containing compact-pol C2 matrix files.
chi : float, default=45
Ellipticity angle chi of the transmitted wave in degrees.
For circular polarization, chi = 45° (right circular) or -45° (left circular).
psi : float, default=0
Orientation angle psi of the transmitted wave in degrees.
For circular polarization, typically 0°.
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 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.
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
-------
None
Results are written to disk as either 'cprvi.tif' or 'cprvi.bin'
in the input folder.
"""
write_flag=True
input_filepaths = cpc2files(in_dir)
output_filepaths = []
if fmt == "bin":
output_filepaths.append(os.path.join(in_dir, "cprvi.bin"))
else:
output_filepaths.append(os.path.join(in_dir, "cprvi.tif"))
process_chunks_parallel(input_filepaths, list(output_filepaths),
win,
write_flag,
process_chunk_cprvi,
*[chi, psi],
block_size=block_size,
max_workers=max_workers,
num_outputs=len(output_filepaths),
cog=cog, comp=comp, ovr=ovr,
progress_callback=progress_callback
)
def process_chunk_cprvi(chunks, window_size, *args, **kwargs):
chi=args[-2]
psi=args[-1]
# print(chi,psi)
chunk_arrays = [np.array(ch) for ch in chunks]
# CPP function
vi_c_raw = process_chunk_cprvicpp( chunk_arrays, window_size, chi, psi )
return np.array(vi_c_raw, copy=True).astype(np.float32)
