Update python samples

samples/python/camera_calibration_show_extrinsics.py

 #!/usr/bin/env python
-# -*- coding: utf-8 -*-
+
+'''
+Plot camera calibration extrinsics.
+
+usage:
+    camera_calibration_show_extrinsics.py [--calibration <input path>] [--cam_width] [--cam_height] [--scale_focal] [--patternCentric ]
+
+default values:
+    --calibration    : left_intrinsics.yml
+    --cam_width      : 0.064/2
+    --cam_height     : 0.048/2
+    --scale_focal    : 40
+    --patternCentric : True
+'''
 
 # Python 2/3 compatibility
 from __future__ import print_function

samples/python/common.py

@@ -222,7 +222,7 @@ def mosaic(w, imgs):
     pad = np.zeros_like(img0)
     imgs = it.chain([img0], imgs)
     rows = grouper(w, imgs, pad)
-    return np.vstack(map(np.hstack, rows))
+    return np.vstack(list(map(np.hstack, rows)))
 
 def getsize(img):
     h, w = img.shape[:2]

samples/python/digits.py

@@ -191,3 +191,4 @@ if __name__ == '__main__':
     model.save('digits_svm.dat')
 
     cv.waitKey(0)
+    cv.destroyAllWindows()

samples/python/digits_video.py

@@ -29,7 +29,7 @@ def main():
         src = sys.argv[1]
     except:
         src = 0
-    cap = video.create_capture(src)
+    cap = video.create_capture(src, fallback='synth:bg={}:noise=0.05'.format(cv.samples.findFile('sudoku.png')))
 
     classifier_fn = 'digits_svm.dat'
     if not os.path.exists(classifier_fn):

samples/python/facedetect.py

@@ -39,13 +39,13 @@ def main():
     except:
         video_src = 0
     args = dict(args)
-    cascade_fn = args.get('--cascade', "data/haarcascades/haarcascade_frontalface_alt.xml")
-    nested_fn  = args.get('--nested-cascade', "data/haarcascades/haarcascade_eye.xml")
+    cascade_fn = args.get('--cascade', "haarcascades/haarcascade_frontalface_alt.xml")
+    nested_fn  = args.get('--nested-cascade', "haarcascades/haarcascade_eye.xml")
 
     cascade = cv.CascadeClassifier(cv.samples.findFile(cascade_fn))
     nested = cv.CascadeClassifier(cv.samples.findFile(nested_fn))
 
-    cam = create_capture(video_src, fallback='synth:bg={}:noise=0.05'.format(cv.samples.findFile('samples/data/lena.jpg')))
+    cam = create_capture(video_src, fallback='synth:bg={}:noise=0.05'.format(cv.samples.findFile('lena.jpg')))
 
     while True:
         _ret, img = cam.read()

samples/python/qrcode.py

@@ -245,4 +245,6 @@ def main():
 
 
 if __name__ == '__main__':
+    print(__doc__)
     main()
+    cv.destroyAllWindows()

samples/python/text_skewness_correction.py

@@ -15,7 +15,7 @@ import argparse
 
 def main():
     parser = argparse.ArgumentParser()
-    parser.add_argument("-i", "--image", required=True, help="path to input image file")
+    parser.add_argument("-i", "--image", default="imageTextR.png", help="path to input image file")
     args = vars(parser.parse_args())
 
     # load the image from disk
@@ -37,9 +37,9 @@ def main():
     coords = cv.findNonZero(thresh)
     angle = cv.minAreaRect(coords)[-1]
     # the `cv.minAreaRect` function returns values in the
-    # range [-90, 0) if the angle is less than -45 we need to add 90 to it
-    if angle < -45:
-        angle = (90 + angle)
+    # range [0, 90) if the angle is more than 45 we need to subtract 90 from it
+    if angle > 45:
+        angle = (angle - 90)
 
     (h, w) = image.shape[:2]
     center = (w // 2, h // 2)
@@ -55,4 +55,6 @@ def main():
 
 
 if __name__ == "__main__":
+    print(__doc__)
     main()
+    cv.destroyAllWindows()