fix type error of slice indices

doc/py_tutorials/py_imgproc/py_pyramids/py_pyramids.markdown

@@ -117,7 +117,7 @@ for i in range(5,0,-1):
 LS = []
 for la,lb in zip(lpA,lpB):
     rows,cols,dpt = la.shape
-    ls = np.hstack((la[:,0:cols/2], lb[:,cols/2:]))
+    ls = np.hstack((la[:,0:cols//2], lb[:,cols//2:]))
     LS.append(ls)
 
 # now reconstruct
@@ -127,7 +127,7 @@ for i in range(1,6):
     ls_ = cv.add(ls_, LS[i])
 
 # image with direct connecting each half
-real = np.hstack((A[:,:cols/2],B[:,cols/2:]))
+real = np.hstack((A[:,:cols//2],B[:,cols//2:]))
 
 cv.imwrite('Pyramid_blending2.jpg',ls_)
 cv.imwrite('Direct_blending.jpg',real)