import pathlib
import numpy as np
import qpimage
from .file_formats import formats, formats_dict, UnknownFileFormatError, \
WrongFileFormatError
def guess_format(path):
"""Determine the file format of a folder or a file"""
for fmt in formats:
if fmt.verify(path):
return fmt.__name__
else:
msg = "Undefined file format: '{}'".format(path)
raise UnknownFileFormatError(msg)
[docs]def load_data(path, fmt=None, bg_data=None, bg_fmt=None,
meta_data={}, holo_kw={}, as_type="float32"):
"""Load experimental data
Parameters
----------
path: str
Path to experimental data file or folder
fmt: str
The file format to use (see `file_formats.formats`).
If set to `None`, the file format is guessed.
bg_data: str
Path to background data file or `qpimage.QPImage`
bg_fmt: str
The file format to use (see `file_formats.formats`)
for the background. If set to `None`, the file format
is be guessed.
meta_data: dict
Meta data (see `qpimage.meta.DATA_KEYS`)
holo_kw: dict
Keyword arguments for hologram data; See
:func:`qpimage.holo.get_field` for valid keyword arguments.
as_type: str
Defines the data type that the input data is casted to.
The default is "float32" which saves memory. If high
numerical accuracy is required (does not apply for a
simple 2D phase analysis), set this to double precision
("float64").
Returns
-------
dataobj: SeriesData or SingleData
Object that gives lazy access to the experimental data.
"""
path = pathlib.Path(path).resolve()
# sanity checks
for kk in meta_data:
if kk not in qpimage.meta.DATA_KEYS:
msg = "Meta data key not allowed: {}".format(kk)
raise ValueError(msg)
# ignore None or nan values in meta_data
for kk in list(meta_data.keys()):
if meta_data[kk] in [np.nan, None]:
meta_data.pop(kk)
if fmt is None:
fmt = guess_format(path)
else:
if not formats_dict[fmt].verify(path):
msg = "Wrong file format '{}' for '{}'!".format(fmt, path)
raise WrongFileFormatError(msg)
dataobj = formats_dict[fmt](path=path,
meta_data=meta_data,
holo_kw=holo_kw,
as_type=as_type)
if bg_data is not None:
if isinstance(bg_data, qpimage.QPImage):
# qpimage instance
dataobj.set_bg(bg_data)
else:
# actual data on disk
bg_path = pathlib.Path(bg_data).resolve()
if bg_fmt is None:
bg_fmt = guess_format(bg_path)
bgobj = formats_dict[bg_fmt](path=bg_path,
meta_data=meta_data,
holo_kw=holo_kw,
as_type=as_type)
dataobj.set_bg(bgobj)
return dataobj