Improve visualization of labelling

doc/examples/plot_label.py

@@ -7,13 +7,14 @@ This example shows how to segment an image with image labelling.
 
 """
 
+import numpy as np
 import matplotlib.pyplot as plt
 import matplotlib.patches as mpatches
 
 from skimage import data
 from skimage.filter import threshold_otsu
 from skimage.segmentation import clear_border
-from skimage.morphology import label
+from skimage.morphology import label, closing, square
 from skimage.measure import regionprops
 
 
@@ -21,11 +22,7 @@ image = data.coins()[50:-50, 50:-50]
 
 # apply threshold
 thresh = threshold_otsu(image)
-bw = image > thresh
-
-fig, ax = plt.subplots(ncols=1, nrows=1, figsize=(6, 6))
-plt.gray()
-ax.imshow(bw)
+bw = closing(image > thresh, square(3))
 
 # remove artifacts connected to image border
 cleared = bw.copy()
@@ -33,6 +30,11 @@ clear_border(cleared)
 
 # label image regions
 label_image = label(cleared)
+borders = np.logical_xor(bw, cleared)
+label_image[borders] = -1
+
+fig, ax = plt.subplots(ncols=1, nrows=1, figsize=(6, 6))
+ax.imshow(label_image)
 
 for region in regionprops(label_image, ['Area', 'BoundingBox']):