def test_06_NaN(self):
"""Regression test of Otsu with NaN in input (issue #624)"""
r = np.random.RandomState()
r.seed(6)
data = r.uniform(size = 100)
data[r.uniform(size = 100) > .8] = np.NaN
self.assertEqual(otsu(data), otsu(data[~ np.isnan(data)]))
self.assertEqual(entropy(data), entropy(data[~ np.isnan(data)]))
self.assertEqual(otsu3(data), otsu3(data[~ np.isnan(data)]))
self.assertEqual(entropy3(data), entropy3(data[~ np.isnan(data)]))
def test_06_NaN(self):
"""Regression test of Otsu with NaN in input (issue #624)"""
r = np.random.RandomState()
r.seed(6)
data = r.uniform(size = 100)
data[r.uniform(size = 100) > .8] = np.NaN
self.assertEqual(otsu(data), otsu(data[~ np.isnan(data)]))
self.assertEqual(entropy(data), entropy(data[~ np.isnan(data)]))
self.assertEqual(otsu3(data), otsu3(data[~ np.isnan(data)]))
self.assertEqual(entropy3(data), entropy3(data[~ np.isnan(data)]))
def test_04_max_threshold(self):
"""Test Otsu with a max_threshold"""
np.random.seed(0)
#
# There should be three peaks with the otsu
# between the second and third
# With a fixed max threshold, the otsu
# should be between the first two peaks.
x0 = np.random.binomial(40,.1,2000).astype(float)/40.0
x1 = np.random.binomial(40,.5,2000).astype(float)/40.0
x2 = np.random.binomial(40,.9,10000).astype(float)/40.0
x = np.concatenate((x0,x1,x2))
self.assertTrue(otsu(x) > .5)
self.assertTrue(otsu(x) < .9)
self.assertTrue(otsu(x,max_threshold=.5) >=.1)
self.assertTrue(otsu(x,max_threshold=.5) <=.5)
def get_otsu_threshold(image, mask = None,
two_class_otsu = True,
use_weighted_variance = True,
assign_middle_to_foreground = True):
if not mask is None:
image = image[mask]
else:
image = np.array(image.flat)
image = image[image >= 0]
if len(image) == 0:
return 1
image, d = log_transform(image)
if two_class_otsu:
if use_weighted_variance:
threshold = otsu(image)
else:
threshold = entropy(image)
else:
if use_weighted_variance:
t1, t2 = otsu3(image)
else:
t1,t2 = entropy3(image)
threshold = t1 if assign_middle_to_foreground else t2
threshold = inverse_log_transform(threshold, d)
return threshold
def get_ridler_calvard_threshold(image, mask = None):
"""Find a threshold using the method of Ridler and Calvard
The reference for this method is:
"Picture Thresholding Using an Iterative Selection Method"
by T. Ridler and S. Calvard, in IEEE Transactions on Systems, Man and
Cybernetics, vol. 8, no. 8, August 1978.
"""
cropped_image = np.array(image.flat) if mask is None else image[mask]
if np.product(cropped_image.shape)<3:
return 0
if np.min(cropped_image) == np.max(cropped_image):
return cropped_image[0]
# We want to limit the dynamic range of the image to 256. Otherwise,
# an image with almost all values near zero can give a bad result.
min_val = np.max(cropped_image)/256;
cropped_image[cropped_image < min_val] = min_val;
im = np.log(cropped_image);
min_val = np.min(im);
max_val = np.max(im);
im = (im - min_val)/(max_val - min_val);
pre_thresh = 0;
# This method needs an initial value to start iterating. Using
# graythresh (Otsu's method) is probably not the best, because the
# Ridler Calvard threshold ends up being too close to this one and in
# most cases has the same exact value.
new_thresh = otsu(im)
delta = 0.00001;
while abs(pre_thresh - new_thresh)>delta:
pre_thresh = new_thresh;
mean1 = np.mean(im[im<pre_thresh]);
mean2 = np.mean(im[im>=pre_thresh]);
new_thresh = np.mean([mean1,mean2]);
return math.exp(min_val + (max_val-min_val)*new_thresh);
def test_04_max_threshold(self):
"""Test Otsu with a max_threshold"""
np.random.seed(0)
#
# There should be three peaks with the otsu
# between the second and third
# With a fixed max threshold, the otsu
# should be between the first two peaks.
x0 = np.random.binomial(40,.1,2000).astype(float)/40.0
x1 = np.random.binomial(40,.5,2000).astype(float)/40.0
x2 = np.random.binomial(40,.9,10000).astype(float)/40.0
x = np.concatenate((x0,x1,x2))
self.assertTrue(otsu(x) > .5)
self.assertTrue(otsu(x) < .9)
self.assertTrue(otsu(x,max_threshold=.5) >=.1)
self.assertTrue(otsu(x,max_threshold=.5) <=.5)
def test_03_min_threshold(self):
"""Test Otsu with a min_threshold"""
np.random.seed(0)
#
# There should be three peaks with the otsu
# between the first and second peaks.
# With a fixed min threshold, the otsu
# should be between the second two peaks.
x0 = np.random.binomial(40, 0.1, 10000).astype(float) / 40.0
x1 = np.random.binomial(40, 0.5, 2000).astype(float) / 40.0
x2 = np.random.binomial(40, 0.9, 2000).astype(float) / 40.0
x = np.concatenate((x0, x1, x2))
self.assertTrue(otsu(x) >= 0.1)
self.assertTrue(otsu(x) <= 0.5)
self.assertTrue(otsu(x, min_threshold=0.5) >= 0.5)
self.assertTrue(otsu(x, min_threshold=0.5) < 0.9)
def test_02_TwoDistributions(self):
"""Test Otsu of two distributions with no points in between is between the two distributions"""
np.random.seed(0)
x0 = np.random.uniform(.1,.4,size=1000)
x1 = np.random.uniform(.6,1.0,size=1000)
x = np.append(x0,x1)
np.random.shuffle(x)
threshold = otsu(x)
self.assertTrue(threshold >= .4)
self.assertTrue(threshold <= .6)
def test_05_threshold_of_flat(self):
"""Test Otsu with a threshold and all input values the same
This is a regression test of an apparent bug where the Otsu
of an all-zero image has a threshold of zero even though
the min_threshold was .1
"""
np.random.seed(0)
x = np.zeros((10,))
self.assertTrue(otsu(x,min_threshold=.1)>=.1)
def test_05_threshold_of_flat(self):
"""Test Otsu with a threshold and all input values the same
This is a regression test of an apparent bug where the Otsu
of an all-zero image has a threshold of zero even though
the min_threshold was .1
"""
np.random.seed(0)
x = np.zeros((10,))
self.assertTrue(otsu(x,min_threshold=.1)>=.1)
def test_02_TwoDistributions(self):
"""Test Otsu of two distributions with no points in between is between the two distributions"""
np.random.seed(0)
x0 = np.random.uniform(.1,.4,size=1000)
x1 = np.random.uniform(.6,1.0,size=1000)
x = np.append(x0,x1)
np.random.shuffle(x)
threshold = otsu(x)
self.assertTrue(threshold >= .4)
self.assertTrue(threshold <= .6)
def test_05_01_otsu_wv(self):
'''Test the weighted variance version of Otsu'''
np.random.seed(0)
image = np.hstack((np.random.exponential(1.5, size=600),
np.random.poisson(15, size=300)))
image.shape = (30, 30)
image = stretch(image)
limage, d = T.log_transform(image)
threshold = otsu(limage)
threshold = T.inverse_log_transform(threshold, d)
expected = image > threshold
workspace, module = self.make_workspace(image)
module.binary.value = A.BINARY
module.threshold_scope.value = I.TS_GLOBAL
module.threshold_method.value = T.TM_OTSU
module.use_weighted_variance.value = I.O_WEIGHTED_VARIANCE
module.two_class_otsu.value = I.O_TWO_CLASS
module.run(workspace)
output = workspace.image_set.get_image(OUTPUT_IMAGE_NAME)
self.assertTrue(np.all(output.pixel_data == expected))
def test_05_01_otsu_wv(self):
'''Test the weighted variance version of Otsu'''
np.random.seed(0)
image = np.hstack((np.random.exponential(1.5,size=600),
np.random.poisson(15,size=300)))
image.shape=(30,30)
image = stretch(image)
limage, d = T.log_transform(image)
threshold = otsu(limage)
threshold = T.inverse_log_transform(threshold, d)
expected = image > threshold
workspace, module = self.make_workspace(image)
module.binary.value = A.BINARY
module.threshold_scope.value = I.TS_GLOBAL
module.threshold_method.value = T.TM_OTSU
module.use_weighted_variance.value = I.O_WEIGHTED_VARIANCE
module.two_class_otsu.value = I.O_TWO_CLASS
module.run(workspace)
output = workspace.image_set.get_image(OUTPUT_IMAGE_NAME)
self.assertTrue(np.all(output.pixel_data == expected))
from centrosome.otsu import otsu
javabridge.start_vm(class_path=bioformats.JARS)
try:
app = wx.PySimpleApp()
figure = matplotlib.figure.Figure()
images = []
objects = []
masks = []
for i, arg in enumerate(sys.argv[1:]):
img = bioformats.load_image(arg)
images.append(
ImageData("Image %d" % (i+1), img,
alpha = 1.0 / (len(sys.argv) - 1),
mode = MODE_COLORIZE))
thresh = otsu(img)
l, _ = label(img >= thresh, np.ones((3,3), bool))
outline_color = tuple([int(idx == i) for idx in range(3)])
objects.append(ObjectsData(
"Objects %d" % (i+1), [l],
outline_color = outline_color,
mode = MODE_LINES))
ii = np.linspace(-1, 1, num = img.shape[0])[:, np.newaxis]
jj = np.linspace(-1, 1, num = img.shape[1])[np.newaxis, :]
mask = (ii ** (2*i+2) + jj ** (2*i+2)) ** (1.0 / (2*i+2)) < .75
masks.append(MaskData("Mask %d" % (i+1), mask,
mode = MODE_LINES,
color = outline_color))
artist = CPImageArtist(images = images, objects=objects, masks = masks)
def test_01_TwoValues(self):
"""Test Otsu of two values is between the two"""
x = otsu([.2,.8])
self.assertTrue(x >= .2)
self.assertTrue(x <= .8)
javabridge.start_vm(class_path=bioformats.JARS)
try:
app = wx.PySimpleApp()
figure = matplotlib.figure.Figure()
images = []
objects = []
masks = []
for i, arg in enumerate(sys.argv[1:]):
img = bioformats.load_image(arg)
images.append(
ImageData("Image %d" % (i + 1),
img,
alpha=1.0 / (len(sys.argv) - 1),
mode=MODE_COLORIZE))
thresh = otsu(img)
l, _ = label(img >= thresh, np.ones((3, 3), bool))
outline_color = tuple([int(idx == i) for idx in range(3)])
objects.append(
ObjectsData("Objects %d" % (i + 1), [l],
outline_color=outline_color,
mode=MODE_LINES))
ii = np.linspace(-1, 1, num=img.shape[0])[:, np.newaxis]
jj = np.linspace(-1, 1, num=img.shape[1])[np.newaxis, :]
mask = (ii**(2 * i + 2) + jj**(2 * i + 2))**(1.0 /
(2 * i + 2)) < .75
masks.append(
MaskData("Mask %d" % (i + 1),
mask,
mode=MODE_LINES,
color=outline_color))
def test_01_TwoValues(self):
"""Test Otsu of two values is between the two"""
x = otsu([.2,.8])
self.assertTrue(x >= .2)
self.assertTrue(x <= .8)
