add unsharpen example.

Author: jesolem

examples/unsharp.py

@@ -0,0 +1,33 @@
+from PIL import Image
+from pylab import *
+from scipy.ndimage import filters
+
+
+"""
+This is an example of unsharp masking using Gaussian blur.
+"""
+
+# load sample eye image from http://en.wikipedia.org/wiki/Unsharp_masking
+im = array(Image.open("unsharpen.jpg").convert("L"), "f")
+
+# create blurred version of the image
+sigma = 3
+blurred = filters.gaussian_filter(im,sigma)
+
+# create unsharp version (no thresholding)
+weight = 0.25
+unsharp = im - 0.25*blurred
+
+
+# plot the original and the unsharpened image
+figure()
+imshow(im)
+gray()
+title("original image")
+
+figure()
+imshow(unsharp)
+gray()
+title("unsharp mask with weight {}".format(weight))
+
+show()