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#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Copyright (c) 2009.
# SMHI,
# Folkborgsvägen 1,
# Norrköping,
# Sweden
# Author(s):
# Martin Raspaud <martin.raspaud@smhi.se>
# Adam Dybbroe <adam.dybbroe@smhi.se>
# This file is part of the mpop.
# mpop is free software: you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# mpop is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
# You should have received a copy of the GNU General Public License
# along with mpop. If not, see <http://www.gnu.org/licenses/>.
"""Miscellaneous image processing tools.
"""
import numpy
def gamma_correction(arr, gamma):
"""Perform gamma correction *g* to an array *arr*, which is assumed
to be in the range [0.0,1.0], and return the resulting array (same
range).
"""
return arr ** (1.0 / gamma)
def crude_stretch(arr, norm = 1, amin = None, amax = None):
"""Perform simple linear stretching (without any cutoff) and normalize."""
if(amin is None):
amin = arr.min()
if(amax is None):
amax = arr.max()
res = (arr - amin) * (norm * 1.0) / (amax - amin)
res = numpy.where(res > norm, norm, res)
res = numpy.where(res < 0, 0, res)
return res
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