Add new tests on python

modules/python/test/test_texture_flow.py

@@ -0,0 +1,52 @@
+#!/usr/bin/env python
+
+'''
+Texture flow direction estimation.
+
+Sample shows how cv2.cornerEigenValsAndVecs function can be used
+to estimate image texture flow direction.
+'''
+
+# Python 2/3 compatibility
+from __future__ import print_function
+
+import numpy as np
+import cv2
+import sys
+
+from tests_common import NewOpenCVTests
+
+
+class texture_flow_test(NewOpenCVTests):
+
+    def test_texture_flow(self):
+
+        fn = '../../../samples/data/pic6.png'
+        img = cv2.imread(fn)
+
+        gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
+        h, w = img.shape[:2]
+
+        eigen = cv2.cornerEigenValsAndVecs(gray, 15, 3)
+        eigen = eigen.reshape(h, w, 3, 2)  # [[e1, e2], v1, v2]
+        flow = eigen[:,:,2]
+
+        vis = img.copy()
+        vis[:] = (192 + np.uint32(vis)) / 2
+        d = 80
+        points =  np.dstack( np.mgrid[d/2:w:d, d/2:h:d] ).reshape(-1, 2)
+
+        textureVectors = []
+        
+        for x, y in np.int32(points):
+            textureVectors.append(np.int32(flow[y, x]*d))
+
+        eps = 0.05
+
+        testTextureVectors = [[0, 0], [0, 0], [0, 0], [0, 0], [0, 0], 
+        [-38, 70], [-79, 3], [0, 0], [0, 0], [-39, 69], [-79, -1],
+        [0, 0], [0, 0], [0, -79], [17, -78], [-48, -63], [65, -46],
+        [-69, -39], [-48, -63], [-45, 66]]
+
+        for i in range(len(textureVectors)):
+            self.assertLessEqual(cv2.norm(textureVectors[i] - testTextureVectors[i], cv2.NORM_L2), eps)