#! /usr/bin/env python3
#
# Copyright 2019 California Institute of Technology
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# ISOFIT: Imaging Spectrometer Optimal FITting
# Author: David R Thompson, david.r.thompson@jpl.nasa.gov
#
from os.path import split, abspath
import numpy as np
from ..core.common import load_spectrum, expand_path, json_load_ascii
from ..core.instrument import Instrument
from ..core.geometry import Geometry
[docs]def generate_noise(config):
"""Add noise to a radiance spectrum or image."""
config = json_load_ascii(config, shell_replace=True)
configdir, configfile = split(abspath(config))
infile = expand_path(configdir, config['input_radiance_file'])
outfile = expand_path(configdir, config['output_radiance_file'])
instrument = Instrument(config['instrument_model'])
geom = Geometry()
if infile.endswith('txt'):
rdn, wl = load_spectrum(infile)
Sy = instrument.Sy(rdn, geom)
rdn_noise = rdn + np.random.multivariate_normal(np.zeros(rdn.shape), Sy)
with open(outfile, 'w') as fout:
for w, r in zip(wl, rdn_noise):
fout.write('%8.5f %8.5f' % (w, r))
else:
raise ValueError("Image cubes not yet implemented.")