Merge pull request #166 from 'vincent-albufera/exemple_modif'

DOC: Improve harris corners and peak detection examples and docstrings.

doc/examples/plot_peak_local_max.py

@@ -0,0 +1,50 @@
+"""
+===============================================================================
+Finding local maxima
+===============================================================================
+
+The ``peak_local_max`` function returns the coordinates of local peaks (maxima)
+in an image. A maximum filter is used for finding local maxima. This operation
+dilates the original image and merges neighboring local maxima closer than the
+size of the dilation. Locations where the original image is equal to the
+dilated image are returned as local maxima.
+
+"""
+from scipy import ndimage
+import matplotlib.pyplot as plt
+from skimage.feature import peak_local_max
+from skimage import data, img_as_float
+
+im = img_as_float(data.coins())
+
+# image_max is the dilation of im with a 20*20 structuring element
+# It is used within peak_local_max function
+image_max = ndimage.maximum_filter(im, size=20, mode='constant')
+
+# Comparison between image_max and im to find the coordinates of local maxima
+coordinates = peak_local_max(im, min_distance=20)
+
+# display results
+plt.figure(figsize=(8, 3))
+plt.subplot(131)
+plt.imshow(im, cmap=plt.cm.gray)
+plt.axis('off')
+plt.title('Original')
+
+plt.subplot(132)
+plt.imshow(image_max, cmap=plt.cm.gray)
+plt.axis('off')
+plt.title('Maximum filter')
+
+plt.subplot(133)
+plt.imshow(im, cmap=plt.cm.gray)
+plt.autoscale(False)
+plt.plot([p[1] for p in coordinates], [p[0] for p in coordinates], 'r.')
+plt.axis('off')
+plt.title('Peak local max')
+
+plt.subplots_adjust(wspace=0.02, hspace=0.02, top=0.9,
+                    bottom=0.02, left=0.02, right=0.98)
+
+plt.show()
+