fpipy

Top-level package for Fabry-Perot Imaging in Python.

fpipy.read_hdt(hdtfile)[source]

Load metadata from a .hdt header file (VTT format).

fpipy.read_ENVI_cfa(filepath, raw_unit='dn', **kwargs)[source]

Read ENVI format CFA data and metadata to an xarray Dataset.

For the VTT format raw ENVI files the ENVI metadata is superfluous and is discarded, with the actual metadata read from the separate VTT header file. Wavelength and fwhm data will be replaced with information from metadata and number of layers etc. are omitted as redundant. Gain and bayer pattern are assumed to be constant within each file.

Parameters
  • filepath (str) – Path to the datafile to be opened, either with or without extension. Expects data and metadata to have extensions .dat and .hdt.

  • raw_unit (str, optional) – Units for the raw data.

  • **kwargs – Keyword arguments to be passed on to xr.open_rasterio.

Returns

dataset – Dataset derived from the raw image data and accompanying metadata. If the ENVI data had an included dark layer, it is separated into its own data variable in the dataset.

Return type

xarray.Dataset

fpipy.raw_to_radiance(raw, **kwargs)[source]

Performs demosaicing and computes radiance from RGB values.

Parameters
  • raw (xarray.Dataset) – A dataset containing the following variables: c.sinv_data, c.wavelength_data´, `c.fwhm_data c.camera_exposure c.cfa_data, c.dark_reference_data,

  • dm_method (str, optional) – {‘bilinear’, ‘DDFAPD’, ‘Malvar2004’, ‘Menon2007’} Demosaicing method. Default is ‘bilinear’. See the colour_demosaicing package for more info on the different methods.

  • keep_variables (list-like, optional) – List of variables to keep in the result, default None. If you wish to keep the intermediate data, pass the relevant names from fpipy.conventions.

Returns

radiances – Includes computed radiance sorted by wavelength along with original metadata.

Return type

xarray.Dataset

fpipy.raw_to_reflectance(raw, whiteraw, keep_variables=None)[source]

Performs demosaicing and computes radiance from RGB values.

Parameters
  • raw (xarray.Dataset) – A dataset containing the following variables: c.cfa_data, c.dark_reference_data, c.sinv_data, c.wavelength_data´, `c.fwhm_data c.camera_exposure

  • white (xarray.Dataset) – Same as raw but for a cube that describes a white reference target.

  • keep_variables (list-like, optional) – List of variables to keep in the result, default None. If you wish to keep the intermediate data, pass the relevant names from fpipy.conventions.

Returns

reflectance – Includes computed radiance and reflectance as data variables sorted by wavelength or just the reflectance DataArray.

Return type

xarray.Dataset or xarray.DataArray

fpipy.radiance_to_reflectance(radiance, white, keep_variables=None)[source]

Computes reflectance from radiance and a white reference cube.

Parameters
  • radiance (xarray.Dataset) – Dataset containing the image(s) to divide by the references.

  • white (xarray.Dataset) – White reference image(s).

  • keep_variables (list-like, optional) – List of variables to keep in the result, default None. If you wish to keep the intermediate data, pass the relevant names from fpipy.conventions.

Returns

reflectance – Dataset containing the reflectance and the original metadata for both datasets indexed by measurement type.

Return type

xarray.Dataset

fpipy.demosaic(cfa, pattern, dm_method)[source]

Perform demosaicing on a DataArray.

Parameters
Returns

Return type

xarray.DataArray

fpipy.subtract_dark(ds, keep_variables=None)[source]

Subtracts dark current reference from image data.

Subtracts a dark reference frame from all the layers in the given raw data and clamps any negative values in the result to zero. The result is stored in the dataset as the variable c.dark_corrected_cfa_data which is overwritten if it exists.

Parameters
  • ds (xarray.DataSet) – Dataset containing the raw images in fpipy.conventions.cfa_data and the dark current reference measurement as fpipy.conventions.dark_reference_data.

  • keep_variables (list-like, optional) – List of variables to keep in the result, default None. If you wish to keep the dark reference data and/or the original raw images, pass a list including the variable names.

Returns

Dataset with the dark corrected data as fpipy.conventions.dark_corrected_cfa_data

Return type

xarray.Dataset