py_tutorials: fix cv2.findContours return val

doc/py_tutorials/py_imgproc/py_contours/py_contour_features/py_contour_features.markdown

@@ -23,7 +23,7 @@ import numpy as np
 
 img = cv2.imread('star.jpg',0)
 ret,thresh = cv2.threshold(img,127,255,0)
-contours,hierarchy = cv2.findContours(thresh, 1, 2)
+im2,contours,hierarchy = cv2.findContours(thresh, 1, 2)
 
 cnt = contours[0]
 M = cv2.moments(cnt)

doc/py_tutorials/py_imgproc/py_contours/py_contours_more_functions/py_contours_more_functions.markdown

@@ -38,8 +38,8 @@ import numpy as np
 
 img = cv2.imread('star.jpg')
 img_gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
-ret, thresh = cv2.threshold(img_gray, 127, 255,0)
-contours,hierarchy = cv2.findContours(thresh,2,1)
+ret,thresh = cv2.threshold(img_gray, 127, 255,0)
+im2,contours,hierarchy = cv2.findContours(thresh,2,1)
 cnt = contours[0]
 
 hull = cv2.convexHull(cnt,returnPoints = False)
@@ -93,9 +93,9 @@ img2 = cv2.imread('star2.jpg',0)
 
 ret, thresh = cv2.threshold(img1, 127, 255,0)
 ret, thresh2 = cv2.threshold(img2, 127, 255,0)
-contours,hierarchy = cv2.findContours(thresh,2,1)
+im2,contours,hierarchy = cv2.findContours(thresh,2,1)
 cnt1 = contours[0]
-contours,hierarchy = cv2.findContours(thresh2,2,1)
+im2,contours,hierarchy = cv2.findContours(thresh2,2,1)
 cnt2 = contours[0]
 
 ret = cv2.matchShapes(cnt1,cnt2,1,0.0)