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Cleaned up adapthist func to use LAB for all RGB->required rest result change

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This commit is contained in:
Steven Silvester
2012-12-01 23:46:52 -06:00
parent 79fb543256
commit 2e1729a9fb
2 changed files with 18 additions and 29 deletions
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skimage/exposure/_adapthist.py
+16 -27
View File
@@ -71,37 +71,26 @@ def adapthist(image, ntiles_x=8, ntiles_y=8, clip_limit=0.01, nbins=256):
.. [1] http://tog.acm.org/resources/GraphicsGems/
.. [2] https://en.wikipedia.org/wiki/CLAHE#CLAHE
'''
# convert to uint image
int_image = skimage.img_as_uint(image)
int_image = rescale_intensity(int_image, out_range=(0, NR_OF_GREY - 1))
# handle color images - CLAHE accepts scalar images only
args = [int_image.copy(), ntiles_x, ntiles_y, clip_limit * nbins, nbins]
if image.ndim == 3:
# check for grayscale
if (np.allclose(image[:, :, 0], image[:, :, 1]) and
np.allclose(image[:, :, 1], image[:, :, 2])):
args[0] = int_image[:, :, 0]
out = _clahe(*args)
image = int_image[:, :, :3]
for channel in range(3):
image[:out.shape[0], :out.shape[1], channel] = out
# for color images, convert to LAB space for processing
else:
lab_img = color.rgb2lab(skimage.img_as_float(image))
l_chan = lab_img[:, :, 0]
l_chan /= np.max(np.abs(l_chan))
l_chan = skimage.img_as_uint(l_chan)
args[0] = rescale_intensity(l_chan, out_range=(0, NR_OF_GREY - 1))
new_l = _clahe(*args).astype(float)
new_l = rescale_intensity(new_l, out_range=(0, 100))
lab_img[:new_l.shape[0], :new_l.shape[1], 0] = new_l
image = color.lab2rgb(lab_img)
image = rescale_intensity(image, out_range=(0, 1))
args = [None, ntiles_x, ntiles_y, clip_limit * nbins, nbins]
if image.ndim > 2:
lab_img = color.rgb2lab(skimage.img_as_float(image))
l_chan = lab_img[:, :, 0]
l_chan /= np.max(np.abs(l_chan))
l_chan = skimage.img_as_uint(l_chan)
args[0] = rescale_intensity(l_chan, out_range=(0, NR_OF_GREY - 1))
new_l = _clahe(*args).astype(float)
new_l = rescale_intensity(new_l, out_range=(0, 100))
lab_img[:new_l.shape[0], :new_l.shape[1], 0] = new_l
image = color.lab2rgb(lab_img)
image = rescale_intensity(image, out_range=(0, 1))
else:
image = skimage.img_as_uint(image)
args[0] = rescale_intensity(image, out_range=(0, NR_OF_GREY - 1))
out = _clahe(*args)
image = int_image
image[:out.shape[0], :out.shape[1]] = out
return rescale_intensity(image)
image = rescale_intensity(image)
return image
def _clahe(image, ntiles_x, ntiles_y, clip_limit, nbins=128):
skimage/exposure/tests/test_exposure.py
+2 -2
View File
@@ -100,8 +100,8 @@ def test_adapthist_grayscale():
nbins=128)
assert_almost_equal = np.testing.assert_almost_equal
assert img.shape == adapted.shape
assert_almost_equal(peak_snr(img, adapted), 106.3020173)
assert_almost_equal(norm_brightness_err(img, adapted), 0.0218686)
assert_almost_equal(peak_snr(img, adapted), 77.5841845)
assert_almost_equal(norm_brightness_err(img, adapted), 0.0376632)
return data, adapted