"""
Thresholding
============
This module contains vairous thresholding routines, including
hysteresis thresholding.
Module towards smart thresholding routines.
"""
__author__ = 'Christoph Kirst <ckirst@rockefeller.edu>'
__license__ = 'MIT License <http://www.opensource.org/licenses/mit-license.php>'
__copyright__ = 'Copyright (c) 2017 by Christoph Kirst, The Rockefeller University, New York City'
import os
import numpy as np
import ClearMap.IO.IO as io;
import pyximport;
#pyximport.install(setup_args={"include_dirs":np.get_include()}, reload_support=True)
old_get_distutils_extension = pyximport.pyximport.get_distutils_extension
[docs]def new_get_distutils_extension(modname, pyxfilename, language_level=None):
extension_mod, setup_args = old_get_distutils_extension(modname, pyxfilename, language_level)
extension_mod.language='c++'
return extension_mod,setup_args
pyximport.pyximport.get_distutils_extension = new_get_distutils_extension
pyximport.install(setup_args = {"include_dirs" : [np.get_include(), os.path.dirname(os.path.abspath(__file__))]},
reload_support=True)
from . import ThresholdingCode as code
###############################################################################
### Hysteresis thresholding
###############################################################################
[docs]def threshold(source, sink = None, threshold = None, hysteresis_threshold = None, seeds = None, background = None):
"""Hysteresis thresholding.
Arguments
---------
source : array
Input source.
sink : array or None
If None, a new array is allocated.
threshold : float
The threshold for the intial seeds.
hysteresis_threshold : float or None
The hysteresis threshold to extend the initial seeds.
If None, no hysteresis thresholding is performed.
seeds : array or None
The seeds from which to start the hysteresis thresholds
background : array or None
Exclude this area from the hysteresis thresholding.
Returns
-------
sink : array
Thresholded output.
"""
if threshold is None and seeds is None:
raise ValueError('The threshold and seeds cannot both be None!');
if source is sink:
raise NotImplementedError("Cannot perform operation in place.")
if sink is None:
sink = np.zeros(source.shape, dtype = 'int8', order = io.order(source));
source_flat = source.reshape(-1, order=io.order(source));
sink_flat = sink.reshape(-1, order=io.order(sink));
strides = np.array(io.element_strides(source));
if seeds is None:
seeds = np.where(source_flat >= threshold)[0];
else:
seeds_flat = seeds.reshape(-1, order=io.order(seeds));
seeds = np.where(seeds_flat)[0];
if hysteresis_threshold is not None:
parameter_index = np.zeros(0, dtype = int);
parameter_double = np.array([hysteresis_threshold], dtype = float);
if background is not None:
background_flat = background.reshape(-1, order=io.order(background));
background_flat = background_flat.view(dtype='uint8')
code.threshold_to_background(source_flat, sink_flat, background_flat, strides, seeds, parameter_index, parameter_double);
else:
code.threshold(source_flat, sink_flat, strides, seeds, parameter_index, parameter_double);
else:
sink_flat[seeds] = 1;
return sink;
###############################################################################
### Tests
###############################################################################
def _test():
import numpy as np
import ClearMap.Visualization.Plot3d as p3d
import ClearMap.ImageProcessing.Thresholding.Thresholding as th
r = np.arange(50);
x,y,z = np.meshgrid(r,r,r);
x,y,z = [i - 25 for i in (x,y,z)];
d = np.exp(-(x*x + y*y +z*z)/10.0**2)
t = th.threshold(d, sink = None, threshold = 0.9, hysteresis_threshold=0.5);
p3d.plot([[d,t]])
Source
