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Addition of examples in the harris and peak local max function

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Vincent Albufera
2012-03-26 15:39:59 +02:00
parent 8c9777b967
commit 2aca8cd791
5 changed files with 67 additions and 92 deletions
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doc/examples/plot_peak_local_max.py
+15 -15
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@@ -1,14 +1,15 @@
"""
===============================================================================
Peak local maximum
Finding local maxima
===============================================================================
The peak local maximum return coordinates of peaks in a image. The maximum
filter is used for finding the maximum peaks in the image. It dilates the
original image and is used within peak local max function to find the
coordinates of maximum peaks, comparing the dilated image with the original.
Then, the peak local max function returns the coordinates of points where
image = dilated image.
The peak local maximum function returns the coordinates of local peaks (maxima)
in a 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
@@ -18,14 +19,13 @@ from skimage.feature import peak_local_max
from skimage import data, img_as_float
im = img_as_float(data.coins())
image = im.copy()
# The image_max is the dilation of im with a 20*20 structuring element
# 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(image, size=20, mode='constant')
image_max = ndimage.maximum_filter(im, size=20, mode='constant')
# Comparison between image_max and im to find the coordinates of maximum peaks
coordinates = peak_local_max(im, min_distance = 20)
# 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))
@@ -42,9 +42,9 @@ plt.title('Maximum filter')
plt.subplot(133)
plt.imshow(im, cmap=plt.cm.gray)
a, b = im.shape
plt.plot([p[1] for p in coordinates],[p[0] for p in coordinates],'r.')
plt.xlim(0,b)
plt.ylim(a,0)
plt.plot([p[1] for p in coordinates], [p[0] for p in coordinates], 'r.')
plt.xlim(0, b)
plt.ylim(a, 0)
plt.axis('off')
plt.title('Peak local max')