ENH fixed stupid bug in quickshift, example

doc/examples/plot_quickshift.py

@@ -0,0 +1,47 @@
+import matplotlib.pyplot as plt
+import numpy as np
+
+from scipy import ndimage
+#from skimage.data import lena
+#from skimage.util import img_as_float
+from skimage.segmentation import quickshift
+
+from IPython.core.debugger import Tracer
+tracer = Tracer()
+
+
+def microstructure(l=256):
+    """
+    Synthetic binary data: binary microstructure with blobs.
+
+    Parameters
+    ----------
+
+    l: int, optional
+        linear size of the returned image
+    """
+    n = 5
+    x, y = np.ogrid[0:l, 0:l]
+    mask = np.zeros((l, l))
+    generator = np.random.RandomState(1)
+    points = l * generator.rand(2, n ** 2)
+    mask[(points[0]).astype(np.int), (points[1]).astype(np.int)] = 1
+    mask = ndimage.gaussian_filter(mask, sigma=l / (4. * n))
+    return (mask > mask.mean()).astype(np.float)
+
+
+#img = img_as_float(lena()[250:300, 250:300])
+img = microstructure(l=50)
+segments = quickshift(img.reshape(50, 50, 1))
+segments = np.unique(segments, return_inverse=True)[1].reshape(50, 50)
+intensities = np.bincount(segments.ravel(), img.ravel())
+counts = np.bincount(segments.ravel())
+intensities /= counts
+
+plt.imshow(img, interpolation='nearest')
+plt.figure()
+plt.imshow(segments, interpolation='nearest')
+plt.figure()
+plt.imshow(intensities[segments], interpolation='nearest')
+plt.show()
+print("num segments: %d" % len(np.unique(segments)))