DHI-GRAS / dg-calibration

Coefficients and functions for calibrating DigitalGlobe imagery in Python

dg_calibration

Coefficients and functions for calibrating DigitalGlobe imagery in Python

Bascially a Python-implementation of https://dg-cms-uploads-production.s3.amazonaws.com/uploads/document/file/209/ABSRADCAL_FLEET_2016v0_Rel20170606.pdf with metadata parsing.

Installation

Requires numpy as single non-trivial dependency. All other dependencies are easily pip-installable.

pip install -r requirements.txt
pip install .

Usage

Compute radiance from digital numbers

from dg_calibration import radiance

imdfile = r'/path/to/some/metadata.IMD'

dn = np.random.randint(0, 6000, size=(3, 20, 30))

rad = radiance.dn_to_radiance(dn, imdfile, band_ids=[3, 2, 1])  # band 4, 3, 2

Compute reflectance from digital numbers or radiance

from dg_calibration import reflectance

refl = reflectance.dn_to_reflectance(dn, imdfile, band_ids=None)  # full band stack

refl = reflectance.radiance_to_reflectance(rad, imdfile, band_ids=[3, 2, 1])

Retrieve gain and offset

from dg_calibration import gain_offset

gain = gain_offset.get_gain_values('WV02')
offset = gain_offset.get_offset_values('GE01')

Testing

python -m pytest -v