python cv2 sample: coherence enhancing

diff --git a/samples/python2/coherence.py b/samples/python2/coherence.py
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+'''\r
+  Coherence-enhancing filtering example\r
+\r
+  inspired by  \r
+    Joachim Weickert "Coherence-Enhancing Shock Filters"\r
+    http://www.mia.uni-saarland.de/Publications/weickert-dagm03.pdf\r
+'''\r
+\r
+import numpy as np\r
+import cv, cv2\r
+\r
+\r
+def coherence_filter(img, sigma = 11, str_sigma = 11, blend = 0.5, iter_n = 4):\r
+    h, w = img.shape[:2]\r
+\r
+    for i in xrange(iter_n):\r
+        print i,\r
+        \r
+        gray = cv2.cvtColor(img, cv.CV_BGR2GRAY)\r
+        eigen = cv2.cornerEigenValsAndVecs(gray, str_sigma, 3)\r
+        eigen = eigen.reshape(h, w, 3, 2)  # [[e1, e2], v1, v2]\r
+        x, y = eigen[:,:,1,0], eigen[:,:,1,1]\r
+        \r
+        gxx = cv2.sobel(gray, cv2.CV_32F, 2, 0, ksize=sigma)\r
+        gxy = cv2.sobel(gray, cv2.CV_32F, 1, 1, ksize=sigma)\r
+        gyy = cv2.sobel(gray, cv2.CV_32F, 0, 2, ksize=sigma)\r
+        gvv = x*x*gxx + 2*x*y*gxy + y*y*gyy\r
+        m = gvv < 0\r
+\r
+        ero = cv2.erode(img, None)\r
+        dil = cv2.dilate(img, None)\r
+        img1 = ero\r
+        img1[m] = dil[m]\r
+        img = np.uint8(img*(1.0 - blend) + img1*blend)\r
+    print 'done'\r
+    return img\r
+\r
+    \r
+if __name__ == '__main__':\r
+    import sys\r
+    try: fn = sys.argv[1]\r
+    except: fn = '../cpp/baboon.jpg'\r
+\r
+    src = cv2.imread(fn)\r
+\r
+    def nothing(*argv):\r
+        pass\r
+\r
+    def update():\r
+        sigma = cv2.getTrackbarPos('sigma', 'control')*2+1\r
+        str_sigma = cv2.getTrackbarPos('str_sigma', 'control')*2+1\r
+        blend = cv2.getTrackbarPos('blend', 'control') / 10.0\r
+        print 'sigma: %d  str_sigma: %d  blend_coef: %f' % (sigma, str_sigma, blend)\r
+        dst = coherence_filter(src, sigma=sigma, str_sigma = str_sigma, blend = blend)\r
+        cv2.imshow('dst', dst)\r
+\r
+    cv2.namedWindow('control', 0)\r
+    cv.CreateTrackbar('sigma', 'control', 9, 15, nothing)\r
+    cv.CreateTrackbar('blend', 'control', 7, 10, nothing)\r
+    cv.CreateTrackbar('str_sigma', 'control', 9, 15, nothing)\r
+\r
+\r
+    print 'Press SPACE to update the image\n'\r
+\r
+    cv2.imshow('src', src)\r
+    update()\r
+    while True:\r
+        ch = cv2.waitKey()\r
+        if ch == ord(' '):\r
+            update()\r
+        if ch == 27:\r
+            break\r