Various Python samples updated for Python 2/3 compatibility.

samples/python2/_coverage.py

@@ -4,6 +4,9 @@
 Utility for measuring python opencv API coverage by samples.
 '''
 
+# Python 2/3 compatibility
+from __future__ import print_function
+
 from glob import glob
 import cv2
 import re
@@ -13,7 +16,7 @@ if __name__ == '__main__':
 
     found = set()
     for fn in glob('*.py'):
-        print ' --- ', fn
+        print(' --- ', fn)
         code = open(fn).read()
         found |= set(re.findall('cv2?\.\w+', code))
 
@@ -23,4 +26,4 @@ if __name__ == '__main__':
         f.write('\n'.join(sorted(cv2_unused)))
 
     r = 1.0 * len(cv2_used) / len(cv2_callable)
-    print '\ncv2 api coverage: %d / %d  (%.1f%%)' % ( len(cv2_used), len(cv2_callable), r*100 )
+    print('\ncv2 api coverage: %d / %d  (%.1f%%)' % ( len(cv2_used), len(cv2_callable), r*100 ))

samples/python2/_doc.py

@@ -5,12 +5,20 @@ Scans current directory for *.py files and reports
 ones with missing __doc__ string.
 '''
 
+# Python 2/3 compatibility
+from __future__ import print_function
+import sys
+PY3 = sys.version_info[0] == 3
+
 from glob import glob
 
 if __name__ == '__main__':
-    print '--- undocumented files:'
+    print('--- undocumented files:')
     for fn in glob('*.py'):
         loc = {}
-        execfile(fn, loc)
+        if PY3:
+            exec(open(fn).read(), loc)
+        else:
+            execfile(fn, loc)
         if '__doc__' not in loc:
-            print fn
+            print(fn)

samples/python2/browse.py

@@ -12,6 +12,14 @@ browse.py [image filename]
 
 '''
 
+# Python 2/3 compatibility
+from __future__ import print_function
+import sys
+PY3 = sys.version_info[0] == 3
+
+if PY3:
+    xrange = range
+
 import numpy as np
 import cv2
 
@@ -19,21 +27,21 @@ import cv2
 import sys
 
 if __name__ == '__main__':
-    print 'This sample shows how to implement a simple hi resolution image navigation.'
-    print 'USAGE: browse.py [image filename]'
-    print
+    print('This sample shows how to implement a simple hi resolution image navigation.')
+    print('USAGE: browse.py [image filename]')
+    print()
 
     if len(sys.argv) > 1:
         fn = sys.argv[1]
-        print 'loading %s ...' % fn
+        print('loading %s ...' % fn)
         img = cv2.imread(fn)
         if img is None:
-            print 'Failed to load fn:', fn
+            print('Failed to load fn:', fn)
             sys.exit(1)
 
     else:
         sz = 4096
-        print 'generating %dx%d procedural image ...' % (sz, sz)
+        print('generating %dx%d procedural image ...' % (sz, sz))
         img = np.zeros((sz, sz), np.uint8)
         track = np.cumsum(np.random.rand(500000, 2)-0.5, axis=0)
         track = np.int32(track*10 + (sz/2, sz/2))

samples/python2/calibrate.py

 #!/usr/bin/env python
 
+# Python 2/3 compatibility
+from __future__ import print_function
+
 import numpy as np
 import cv2
 
@@ -41,10 +44,10 @@ if __name__ == '__main__':
     img_points = []
     h, w = 0, 0
     for fn in img_names:
-        print 'processing %s...' % fn,
+        print('processing %s...' % fn,)
         img = cv2.imread(fn, 0)
         if img is None:
-          print "Failed to load", fn
+          print("Failed to load", fn)
           continue
 
         h, w = img.shape[:2]
@@ -58,15 +61,15 @@ if __name__ == '__main__':
             path, name, ext = splitfn(fn)
             cv2.imwrite('%s/%s_chess.bmp' % (debug_dir, name), vis)
         if not found:
-            print 'chessboard not found'
+            print('chessboard not found')
             continue
         img_points.append(corners.reshape(-1, 2))
         obj_points.append(pattern_points)
 
-        print 'ok'
+        print('ok')
 
     rms, camera_matrix, dist_coefs, rvecs, tvecs = cv2.calibrateCamera(obj_points, img_points, (w, h), None, None)
-    print "RMS:", rms
-    print "camera matrix:\n", camera_matrix
-    print "distortion coefficients: ", dist_coefs.ravel()
+    print("RMS:", rms)
+    print("camera matrix:\n", camera_matrix)
+    print("distortion coefficients: ", dist_coefs.ravel())
     cv2.destroyAllWindows()

samples/python2/camshift.py

@@ -22,6 +22,14 @@ Keys:
     b     - toggle back-projected probability visualization
 '''
 
+# Python 2/3 compatibility
+from __future__ import print_function
+import sys
+PY3 = sys.version_info[0] == 3
+
+if PY3:
+    xrange = range
+
 import numpy as np
 import cv2
 
@@ -103,7 +111,7 @@ class App(object):
                 try:
                     cv2.ellipse(vis, track_box, (0, 0, 255), 2)
                 except:
-                    print track_box
+                    print(track_box)
 
             cv2.imshow('camshift', vis)
 
@@ -121,5 +129,5 @@ if __name__ == '__main__':
         video_src = sys.argv[1]
     except:
         video_src = 0
-    print __doc__
+    print(__doc__)
     App(video_src).run()

samples/python2/coherence.py

@@ -9,6 +9,14 @@ inspired by
   http://www.mia.uni-saarland.de/Publications/weickert-dagm03.pdf
 '''
 
+# Python 2/3 compatibility
+from __future__ import print_function
+import sys
+PY3 = sys.version_info[0] == 3
+
+if PY3:
+    xrange = range
+
 import numpy as np
 import cv2
 
@@ -16,7 +24,7 @@ def coherence_filter(img, sigma = 11, str_sigma = 11, blend = 0.5, iter_n = 4):
     h, w = img.shape[:2]
 
     for i in xrange(iter_n):
-        print i,
+        print(i)
 
         gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
         eigen = cv2.cornerEigenValsAndVecs(gray, str_sigma, 3)
@@ -34,7 +42,7 @@ def coherence_filter(img, sigma = 11, str_sigma = 11, blend = 0.5, iter_n = 4):
         img1 = ero
         img1[m] = dil[m]
         img = np.uint8(img*(1.0 - blend) + img1*blend)
-    print 'done'
+    print('done')
     return img
 
 
@@ -54,7 +62,7 @@ if __name__ == '__main__':
         sigma = cv2.getTrackbarPos('sigma', 'control')*2+1
         str_sigma = cv2.getTrackbarPos('str_sigma', 'control')*2+1
         blend = cv2.getTrackbarPos('blend', 'control') / 10.0
-        print 'sigma: %d  str_sigma: %d  blend_coef: %f' % (sigma, str_sigma, blend)
+        print('sigma: %d  str_sigma: %d  blend_coef: %f' % (sigma, str_sigma, blend))
         dst = coherence_filter(src, sigma=sigma, str_sigma = str_sigma, blend = blend)
         cv2.imshow('dst', dst)
 
@@ -64,7 +72,7 @@ if __name__ == '__main__':
     cv2.createTrackbar('str_sigma', 'control', 9, 15, nothing)
 
 
-    print 'Press SPACE to update the image\n'
+    print('Press SPACE to update the image\n')
 
     cv2.imshow('src', src)
     update()

samples/python2/common.py

@@ -4,6 +4,14 @@
 This module contains some common routines used by other samples.
 '''
 
+# Python 2/3 compatibility
+from __future__ import print_function
+import sys
+PY3 = sys.version_info[0] == 3
+
+if PY3:
+    from functools import reduce
+
 import numpy as np
 import cv2
 
@@ -70,7 +78,8 @@ def mtx2rvec(R):
     axis = np.cross(vt[0], vt[1])
     return axis * np.arctan2(s, c)
 
-def draw_str(dst, (x, y), s):
+def draw_str(dst, target, s):
+    x, y = target
     cv2.putText(dst, s, (x+1, y+1), cv2.FONT_HERSHEY_PLAIN, 1.0, (0, 0, 0), thickness = 2, lineType=cv2.LINE_AA)
     cv2.putText(dst, s, (x, y), cv2.FONT_HERSHEY_PLAIN, 1.0, (255, 255, 255), lineType=cv2.LINE_AA)
 
@@ -135,12 +144,12 @@ def clock():
 
 @contextmanager
 def Timer(msg):
-    print msg, '...',
+    print(msg, '...',)
     start = clock()
     try:
         yield
     finally:
-        print "%.2f ms" % ((clock()-start)*1000)
+        print("%.2f ms" % ((clock()-start)*1000))
 
 class StatValue:
     def __init__(self, smooth_coef = 0.5):
@@ -192,7 +201,11 @@ class RectSelector:
 def grouper(n, iterable, fillvalue=None):
     '''grouper(3, 'ABCDEFG', 'x') --> ABC DEF Gxx'''
     args = [iter(iterable)] * n
-    return it.izip_longest(fillvalue=fillvalue, *args)
+    if PY3:
+        output = it.zip_longest(fillvalue=fillvalue, *args)
+    else:
+        output = it.izip_longest(fillvalue=fillvalue, *args)
+    return output
 
 def mosaic(w, imgs):
     '''Make a grid from images.
@@ -201,7 +214,10 @@ def mosaic(w, imgs):
     imgs -- images (must have same size and format)
     '''
     imgs = iter(imgs)
-    img0 = imgs.next()
+    if PY3:
+        img0 = next(imgs)
+    else:
+        img0 = imgs.next()
     pad = np.zeros_like(img0)
     imgs = it.chain([img0], imgs)
     rows = grouper(w, imgs, pad)

samples/python2/deconvolution.py

@@ -30,6 +30,9 @@ Examples:
 [1] http://en.wikipedia.org/wiki/Wiener_deconvolution
 '''
 
+# Python 2/3 compatibility
+from __future__ import print_function
+
 import numpy as np
 import cv2
 
@@ -63,7 +66,7 @@ def defocus_kernel(d, sz=65):
 
 
 if __name__ == '__main__':
-    print __doc__
+    print(__doc__)
     import sys, getopt
     opts, args = getopt.getopt(sys.argv[1:], '', ['circle', 'angle=', 'd=', 'snr='])
     opts = dict(opts)
@@ -76,7 +79,7 @@ if __name__ == '__main__':
 
     img = cv2.imread(fn, 0)
     if img is None:
-        print 'Failed to load fn1:', fn1
+        print('Failed to load fn1:', fn1)
         sys.exit(1)
 
     img = np.float32(img)/255.0

samples/python2/demo.py

@@ -4,16 +4,25 @@
 Sample-launcher application.
 '''
 
+# Python 2/3 compatibility
+from __future__ import print_function
+import sys
+PY3 = sys.version_info[0] == 3
+
 # local modules
 from common import splitfn
 
 # built-in modules
-import sys
 import webbrowser
-import Tkinter as tk
 from glob import glob
 from subprocess import Popen
-from ScrolledText import ScrolledText
+
+if PY3:
+    import tkinter as tk
+    from tkinter.scrolledtext import ScrolledText
+else:
+    import Tkinter as tk
+    from ScrolledText import ScrolledText
 
 
 #from IPython.Shell import IPShellEmbed
@@ -97,14 +106,17 @@ class App:
         run_btn.pack()
 
     def on_link(self, url):
-        print url
+        print(url)
         webbrowser.open(url)
 
     def on_demo_select(self, evt):
         name = self.demos_lb.get( self.demos_lb.curselection()[0] )
         fn = self.samples[name]
         loc = {}
-        execfile(fn, loc)
+        if PY3:
+            exec(open(fn).read(), loc)
+        else:
+            execfile(fn, loc)
         descr = loc.get('__doc__', 'no-description')
 
         self.linker.reset()
@@ -152,7 +164,7 @@ class App:
 
     def on_run(self, *args):
         cmd = self.cmd_entry.get()
-        print 'running:', cmd
+        print('running:', cmd)
         Popen(sys.executable + ' ' + cmd, shell=True)
 
     def run(self):

samples/python2/dft.py

 #!/usr/bin/env python
 
+# Python 2/3 compatibility
+from __future__ import print_function
+
 import cv2
 import numpy as np
 import sys
@@ -57,7 +60,7 @@ if __name__ == "__main__":
         im = cv2.imread(sys.argv[1])
     else :
         im = cv2.imread('../data/baboon.jpg')
-        print "usage : python dft.py <image_file>"
+        print("usage : python dft.py <image_file>")
 
     # convert to grayscale
     im = cv2.cvtColor(im, cv2.COLOR_BGR2GRAY)

samples/python2/distrans.py

@@ -11,6 +11,8 @@ Keys:
   v     - toggle voronoi mode
 '''
 
+# Python 2/3 compatibility
+from __future__ import print_function
 
 import numpy as np
 import cv2
@@ -23,11 +25,11 @@ if __name__ == '__main__':
         fn = sys.argv[1]
     except:
         fn = '../data/fruits.jpg'
-    print __doc__
+    print(__doc__)
 
     img = cv2.imread(fn, 0)
     if img is None:
-        print 'Failed to load fn:', fn
+        print('Failed to load fn:', fn)
         sys.exit(1)
 
     cm = make_cmap('jet')
@@ -62,7 +64,7 @@ if __name__ == '__main__':
             break
         if ch == ord('v'):
             voronoi = not voronoi
-            print 'showing', ['distance', 'voronoi'][voronoi]
+            print('showing', ['distance', 'voronoi'][voronoi])
             update()
         if need_update:
             update()

samples/python2/edge.py

@@ -10,6 +10,9 @@ Usage:
 
 '''
 
+# Python 2/3 compatibility
+from __future__ import print_function
+
 import cv2
 
 # relative module
@@ -20,7 +23,7 @@ import sys
 
 
 if __name__ == '__main__':
-    print __doc__
+    print(__doc__)
 
     try:
         fn = sys.argv[1]

samples/python2/facedetect.py

 #!/usr/bin/env python
 
+# Python 2/3 compatibility
+from __future__ import print_function
+
 import numpy as np
 import cv2
 
@@ -24,7 +27,7 @@ def draw_rects(img, rects, color):
 
 if __name__ == '__main__':
     import sys, getopt
-    print help_message
+    print(help_message)
 
     args, video_src = getopt.getopt(sys.argv[1:], '', ['cascade=', 'nested-cascade='])
     try:

samples/python2/fitline.py

@@ -22,6 +22,11 @@ f     - change distance function
 ESC   - exit
 '''
 
+# Python 2/3 compatibility
+from __future__ import print_function
+import sys
+PY3 = sys.version_info[0] == 3
+
 import numpy as np
 import cv2
 
@@ -43,7 +48,11 @@ def sample_line(p1, p2, n, noise=0.0):
     return p1 + (p2-p1)*t + np.random.normal(size=(n, 2))*noise
 
 dist_func_names = it.cycle('DIST_L2 DIST_L1 DIST_L12 DIST_FAIR DIST_WELSCH DIST_HUBER'.split())
-cur_func_name = dist_func_names.next()
+
+if PY3:
+    cur_func_name = next(dist_func_names)
+else:
+    cur_func_name = dist_func_names.next()
 
 def update(_=None):
     noise = cv2.getTrackbarPos('noise', 'fit line')
@@ -71,7 +80,7 @@ def update(_=None):
     cv2.imshow('fit line', img)
 
 if __name__ == '__main__':
-    print __doc__
+    print(__doc__)
 
     cv2.namedWindow('fit line')
     cv2.createTrackbar('noise', 'fit line', 3, 50, update)
@@ -81,6 +90,9 @@ if __name__ == '__main__':
         update()
         ch = cv2.waitKey(0) & 0xFF
         if ch == ord('f'):
-            cur_func_name = dist_func_names.next()
+            if PY3:
+                cur_func_name = next(dist_func_names)
+            else:
+                cur_func_name = dist_func_names.next()
         if ch == 27:
             break

samples/python2/floodfill.py

@@ -14,6 +14,9 @@ Keys:
   ESC   - exit
 '''
 
+# Python 2/3 compatibility
+from __future__ import print_function
+
 import numpy as np
 import cv2
 
@@ -23,11 +26,11 @@ if __name__ == '__main__':
         fn = sys.argv[1]
     except:
         fn = '../data/fruits.jpg'
-    print __doc__
+    print(__doc__)
 
     img = cv2.imread(fn, True)
     if img is None:
-        print 'Failed to load image file:', fn
+        print('Failed to load image file:', fn)
         sys.exit(1)
 
     h, w = img.shape[:2]
@@ -68,10 +71,10 @@ if __name__ == '__main__':
             break
         if ch == ord('f'):
             fixed_range = not fixed_range
-            print 'using %s range' % ('floating', 'fixed')[fixed_range]
+            print('using %s range' % ('floating', 'fixed')[fixed_range])
             update()
         if ch == ord('c'):
             connectivity = 12-connectivity
-            print 'connectivity =', connectivity
+            print('connectivity =', connectivity)
             update()
     cv2.destroyAllWindows()

samples/python2/gabor_threads.py

@@ -14,6 +14,9 @@ gabor_threads.py [image filename]
 
 '''
 
+# Python 2/3 compatibility
+from __future__ import print_function
+
 import numpy as np
 import cv2
 from multiprocessing.pool import ThreadPool
@@ -48,7 +51,7 @@ if __name__ == '__main__':
     import sys
     from common import Timer
 
-    print __doc__
+    print(__doc__)
     try:
         img_fn = sys.argv[1]
     except:
@@ -56,7 +59,7 @@ if __name__ == '__main__':
 
     img = cv2.imread(img_fn)
     if img is None:
-        print 'Failed to load image file:', img_fn
+        print('Failed to load image file:', img_fn)
         sys.exit(1)
 
     filters = build_filters()
@@ -66,7 +69,7 @@ if __name__ == '__main__':
     with Timer('running multi-threaded'):
         res2 = process_threaded(img, filters)
 
-    print 'res1 == res2: ', (res1 == res2).all()
+    print('res1 == res2: ', (res1 == res2).all())
     cv2.imshow('img', img)
     cv2.imshow('result', res2)
     cv2.waitKey()

samples/python2/grabcut.py

@@ -27,6 +27,9 @@ Key 's' - To save the results
 ===============================================================================
 '''
 
+# Python 2/3 compatibility
+from __future__ import print_function
+
 import numpy as np
 import cv2
 import sys
@@ -72,13 +75,13 @@ def onmouse(event,x,y,flags,param):
         cv2.rectangle(img,(ix,iy),(x,y),BLUE,2)
         rect = (min(ix,x),min(iy,y),abs(ix-x),abs(iy-y))
         rect_or_mask = 0
-        print " Now press the key 'n' a few times until no further change \n"
+        print(" Now press the key 'n' a few times until no further change \n")
 
     # draw touchup curves
 
     if event == cv2.EVENT_LBUTTONDOWN:
         if rect_over == False:
-            print "first draw rectangle \n"
+            print("first draw rectangle \n")
         else:
             drawing = True
             cv2.circle(img,(x,y),thickness,value['color'],-1)
@@ -98,14 +101,14 @@ def onmouse(event,x,y,flags,param):
 if __name__ == '__main__':
 
     # print documentation
-    print __doc__
+    print(__doc__)
 
     # Loading images
     if len(sys.argv) == 2:
         filename = sys.argv[1] # for drawing purposes
     else:
-        print "No input image given, so loading default image, ../data/lena.jpg \n"
-        print "Correct Usage: python grabcut.py <filename> \n"
+        print("No input image given, so loading default image, ../data/lena.jpg \n")
+        print("Correct Usage: python grabcut.py <filename> \n")
         filename = '../data/lena.jpg'
 
     img = cv2.imread(filename)
@@ -119,8 +122,8 @@ if __name__ == '__main__':
     cv2.setMouseCallback('input',onmouse)
     cv2.moveWindow('input',img.shape[1]+10,90)
 
-    print " Instructions: \n"
-    print " Draw a rectangle around the object using right mouse button \n"
+    print(" Instructions: \n")
+    print(" Draw a rectangle around the object using right mouse button \n")
 
     while(1):
 
@@ -132,10 +135,10 @@ if __name__ == '__main__':
         if k == 27:         # esc to exit
             break
         elif k == ord('0'): # BG drawing
-            print " mark background regions with left mouse button \n"
+            print(" mark background regions with left mouse button \n")
             value = DRAW_BG
         elif k == ord('1'): # FG drawing
-            print " mark foreground regions with left mouse button \n"
+            print(" mark foreground regions with left mouse button \n")
             value = DRAW_FG
         elif k == ord('2'): # PR_BG drawing
             value = DRAW_PR_BG
@@ -145,9 +148,9 @@ if __name__ == '__main__':
             bar = np.zeros((img.shape[0],5,3),np.uint8)
             res = np.hstack((img2,bar,img,bar,output))
             cv2.imwrite('grabcut_output.png',res)
-            print " Result saved as image \n"
+            print(" Result saved as image \n")
         elif k == ord('r'): # reset everything
-            print "resetting \n"
+            print("resetting \n")
             rect = (0,0,1,1)
             drawing = False
             rectangle = False
@@ -158,8 +161,8 @@ if __name__ == '__main__':
             mask = np.zeros(img.shape[:2],dtype = np.uint8) # mask initialized to PR_BG
             output = np.zeros(img.shape,np.uint8)           # output image to be shown
         elif k == ord('n'): # segment the image
-            print """ For finer touchups, mark foreground and background after pressing keys 0-3
-            and again press 'n' \n"""
+            print(""" For finer touchups, mark foreground and background after pressing keys 0-3
+            and again press 'n' \n""")
             if (rect_or_mask == 0):         # grabcut with rect
                 bgdmodel = np.zeros((1,65),np.float64)
                 fgdmodel = np.zeros((1,65),np.float64)

samples/python2/houghcircles.py

@@ -6,13 +6,16 @@ Usage: ./houghcircles.py [<image_name>]
 image argument defaults to ../data/board.jpg
 '''
 
+# Python 2/3 compatibility
+from __future__ import print_function
+
 import cv2
 import numpy as np
 import sys
 
 if __name__ == '__main__':
 
-    print __doc__
+    print(__doc__)
     try:
         fn = sys.argv[1]
     except:

samples/python2/houghlines.py

@@ -4,6 +4,9 @@ This example illustrates how to use Hough Transform to find lines
 Usage: ./houghlines.py [<image_name>]
 image argument defaults to ../data/pic1.png
 '''
+# Python 2/3 compatibility
+from __future__ import print_function
+
 import cv2
 import numpy as np
 import sys
@@ -15,7 +18,7 @@ if __name__ == '__main__':
         fn = sys.argv[1]
     except:
         fn = "../data/pic1.png"
-    print __doc__
+    print(__doc__)
     src = cv2.imread(fn)
     dst = cv2.Canny(src, 50, 200)
     cdst = cv2.cvtColor(dst, cv2.COLOR_GRAY2BGR)

samples/python2/inpaint.py

@@ -15,6 +15,9 @@ Keys:
   ESC   - exit
 '''
 
+# Python 2/3 compatibility
+from __future__ import print_function
+
 import numpy as np
 import cv2
 from common import Sketcher
@@ -26,11 +29,11 @@ if __name__ == '__main__':
     except:
         fn = '../data/fruits.jpg'
 
-    print __doc__
+    print(__doc__)
 
     img = cv2.imread(fn)
     if img is None:
-        print 'Failed to load image file:', fn
+        print('Failed to load image file:', fn)
         sys.exit(1)
 
     img_mark = img.copy()

samples/python2/kalman.py

@@ -11,6 +11,13 @@
    Pressing any key (except ESC) will reset the tracking with a different speed.
    Pressing ESC will stop the program.
 """
+# Python 2/3 compatibility
+import sys
+PY3 = sys.version_info[0] == 3
+
+if PY3:
+    long = int
+
 import cv2
 from math import cos, sin
 import numpy as np
@@ -21,7 +28,7 @@ if __name__ == "__main__":
     img_width = 500
     kalman = cv2.KalmanFilter(2, 1, 0)
 
-    code = -1L
+    code = long(-1)
 
     cv2.namedWindow("Kalman")
 

samples/python2/lappyr.py

@@ -12,6 +12,14 @@ References:
 Alexander Mordvintsev 6/10/12
 '''
 
+# Python 2/3 compatibility
+from __future__ import print_function
+import sys
+PY3 = sys.version_info[0] == 3
+
+if PY3:
+    xrange = range
+
 import numpy as np
 import cv2
 import video
@@ -38,7 +46,7 @@ def merge_lappyr(levels):
 
 if __name__ == '__main__':
     import sys
-    print __doc__
+    print(__doc__)
 
     try:
         fn = sys.argv[1]

samples/python2/lk_homography.py

@@ -20,6 +20,9 @@ SPACE - start tracking
 r     - toggle RANSAC
 '''
 
+# Python 2/3 compatibility
+from __future__ import print_function
+
 import numpy as np
 import cv2
 import video
@@ -108,7 +111,7 @@ def main():
     except:
         video_src = 0
 
-    print __doc__
+    print(__doc__)
     App(video_src).run()
     cv2.destroyAllWindows()
 

samples/python2/lk_track.py

@@ -18,6 +18,9 @@ Keys
 ESC - exit
 '''
 
+# Python 2/3 compatibility
+from __future__ import print_function
+
 import numpy as np
 import cv2
 import video
@@ -93,7 +96,7 @@ def main():
     except:
         video_src = 0
 
-    print __doc__
+    print(__doc__)
     App(video_src).run()
     cv2.destroyAllWindows()
 

samples/python2/logpolar.py

 #!/usr/bin/env python
+
+# Python 2/3 compatibility
+from __future__ import print_function
+
 import cv2
 
 if __name__ == '__main__':
@@ -10,7 +14,7 @@ if __name__ == '__main__':
 
     img = cv2.imread(fn)
     if img is None:
-        print 'Failed to load image file:', fn
+        print('Failed to load image file:', fn)
         sys.exit(1)
 
     img2 = cv2.logPolar(img, (img.shape[0]/2, img.shape[1]/2), 40, cv2.WARP_FILL_OUTLIERS)

samples/python2/morphology.py

@@ -12,12 +12,17 @@ Keys:
   ESC - exit
 '''
 
+# Python 2/3 compatibility
+from __future__ import print_function
+import sys
+PY3 = sys.version_info[0] == 3
+
 import numpy as np
 import cv2
 
 
 if __name__ == '__main__':
-    print __doc__
+    print(__doc__)
 
     import sys
     from itertools import cycle
@@ -31,15 +36,20 @@ if __name__ == '__main__':
     img = cv2.imread(fn)
 
     if img is None:
-        print 'Failed to load image file:', fn
+        print('Failed to load image file:', fn)
         sys.exit(1)
 
     cv2.imshow('original', img)
 
     modes = cycle(['erode/dilate', 'open/close', 'blackhat/tophat', 'gradient'])
     str_modes = cycle(['ellipse', 'rect', 'cross'])
-    cur_mode = modes.next()
-    cur_str_mode = str_modes.next()
+
+    if PY3:
+        cur_mode = next(modes)
+        cur_str_mode = next(str_modes)
+    else:
+        cur_mode = modes.next()
+        cur_str_mode = str_modes.next()
 
     def update(dummy=None):
         sz = cv2.getTrackbarPos('op/size', 'morphology')
@@ -73,8 +83,14 @@ if __name__ == '__main__':
         if ch == 27:
             break
         if ch == ord('1'):
-            cur_mode = modes.next()
+            if PY3:
+                cur_mode = next(modes)
+            else:
+                cur_mode = modes.next()
         if ch == ord('2'):
-            cur_str_mode = str_modes.next()
+            if PY3:
+                cur_str_mode = next(str_modes)
+            else:
+                cur_str_mode = str_modes.next()
         update()
     cv2.destroyAllWindows()

samples/python2/mosse.py

@@ -21,6 +21,14 @@ Keys:
     http://www.cs.colostate.edu/~bolme/publications/Bolme2010Tracking.pdf
 '''
 
+# Python 2/3 compatibility
+from __future__ import print_function
+import sys
+PY3 = sys.version_info[0] == 3
+
+if PY3:
+    xrange = range
+
 import numpy as np
 import cv2
 from common import draw_str, RectSelector
@@ -178,7 +186,7 @@ class App:
 
 
 if __name__ == '__main__':
-    print __doc__
+    print (__doc__)
     import sys, getopt
     opts, args = getopt.getopt(sys.argv[1:], '', ['pause'])
     opts = dict(opts)

samples/python2/mouse_and_match.py

@@ -8,6 +8,10 @@ Demonstrate using a mouse to interact with an image:
  When they let go of the mouse, it correlates (using matchTemplate) that patch with the image.
  ESC to exit
 '''
+
+# Python 2/3 compatibility
+from __future__ import print_function
+
 import numpy as np
 import cv2
 
@@ -46,7 +50,7 @@ def onmouse(event, x, y, flags, param):
             cv2.rectangle(img, (sel[0], sel[1]), (sel[2], sel[3]), (0,255,255), 1)
             cv2.imshow("gray", img)
         else:
-            print "selection is complete"
+            print("selection is complete")
             drag_start = None
 
 if __name__ == '__main__':
@@ -61,7 +65,7 @@ if __name__ == '__main__':
     for infile in glob.glob( os.path.join(path, '*.*') ):
         ext = os.path.splitext(infile)[1][1:] #get the filename extenstion
         if ext == "png" or ext == "jpg" or ext == "bmp" or ext == "tiff" or ext == "pbm":
-            print infile
+            print(infile)
 
             img=cv2.imread(infile,1)
             if img == None:

samples/python2/opencv_version.py

 #!/usr/bin/env python
 
+# Python 2/3 compatibility
+from __future__ import print_function
+
 import cv2
 
 if __name__ == '__main__':
@@ -10,9 +13,9 @@ if __name__ == '__main__':
         param = ""
 
     if ("--build" == param):
-        print cv2.getBuildInformation()
+        print(cv2.getBuildInformation())
     elif ("--help" == param):
-        print "\t--build\n\t\tprint complete build info"
-        print "\t--help\n\t\tprint this help"
+        print("\t--build\n\t\tprint complete build info")
+        print("\t--help\n\t\tprint this help")
     else:
-        print "Welcome to OpenCV"
+        print("Welcome to OpenCV")

samples/python2/peopledetect.py

 #!/usr/bin/env python
 
+# Python 2/3 compatibility
+from __future__ import print_function
+
 import numpy as np
 import cv2
 
@@ -27,20 +30,20 @@ if __name__ == '__main__':
     from glob import glob
     import itertools as it
 
-    print help_message
+    print(help_message)
 
     hog = cv2.HOGDescriptor()
     hog.setSVMDetector( cv2.HOGDescriptor_getDefaultPeopleDetector() )
 
     for fn in it.chain(*map(glob, sys.argv[1:])):
-        print fn, ' - ',
+        print(fn, ' - ',)
         try:
             img = cv2.imread(fn)
             if img is None:
-                print 'Failed to load image file:', fn
+                print('Failed to load image file:', fn)
                 continue
         except:
-            print 'loading error'
+            print('loading error')
             continue
 
         found, w = hog.detectMultiScale(img, winStride=(8,8), padding=(32,32), scale=1.05)
@@ -53,7 +56,7 @@ if __name__ == '__main__':
                 found_filtered.append(r)
         draw_detections(img, found)
         draw_detections(img, found_filtered, 3)
-        print '%d (%d) found' % (len(found_filtered), len(found))
+        print('%d (%d) found' % (len(found_filtered), len(found)))
         cv2.imshow('img', img)
         ch = 0xFF & cv2.waitKey()
         if ch == 27:

samples/python2/squares.py

@@ -6,6 +6,13 @@ Simple "Square Detector" program.
 Loads several images sequentially and tries to find squares in each image.
 '''
 
+# Python 2/3 compatibility 
+import sys
+PY3 = sys.version_info[0] == 3
+
+if PY3:
+    xrange = range
+
 import numpy as np
 import cv2
 

samples/python2/turing.py

@@ -7,6 +7,14 @@ Multiscale Turing Patterns generator
 Inspired by http://www.jonathanmccabe.com/Cyclic_Symmetric_Multi-Scale_Turing_Patterns.pdf
 '''
 
+# Python 2/3 compatibility
+from __future__ import print_function
+import sys
+PY3 = sys.version_info[0] == 3
+
+if PY3:
+    xrange = range
+
 import numpy as np
 import cv2
 from common import draw_str
@@ -20,7 +28,7 @@ Press ESC to stop.
 '''
 
 if __name__ == '__main__':
-    print help_message
+    print(help_message)
 
     w, h = 512, 512
 
@@ -30,7 +38,7 @@ if __name__ == '__main__':
     if '-o' in args:
         fn = args['-o']
         out = cv2.VideoWriter(args['-o'], cv2.VideoWriter_fourcc(*'DIB '), 30.0, (w, h), False)
-        print 'writing %s ...' % fn
+        print('writing %s ...' % fn)
 
     a = np.zeros((h, w), np.float32)
     cv2.randu(a, np.array([0]), np.array([1]))

samples/python2/video.py

@@ -29,6 +29,9 @@ Keys:
 
 '''
 
+# Python 2/3 compatibility
+from __future__ import print_function
+
 import numpy as np
 from numpy import pi, sin, cos
 
@@ -162,7 +165,7 @@ def create_capture(source = 0, fallback = presets['chess']):
             cap.set(cv2.CAP_PROP_FRAME_WIDTH, w)
             cap.set(cv2.CAP_PROP_FRAME_HEIGHT, h)
     if cap is None or not cap.isOpened():
-        print 'Warning: unable to open video source: ', source
+        print('Warning: unable to open video source: ', source)
         if fallback is not None:
             return create_capture(fallback, None)
     return cap
@@ -171,7 +174,7 @@ if __name__ == '__main__':
     import sys
     import getopt
 
-    print __doc__
+    print(__doc__)
 
     args, sources = getopt.getopt(sys.argv[1:], '', 'shotdir=')
     args = dict(args)
@@ -194,6 +197,6 @@ if __name__ == '__main__':
             for i, img in enumerate(imgs):
                 fn = '%s/shot_%d_%03d.bmp' % (shotdir, i, shot_idx)
                 cv2.imwrite(fn, img)
-                print fn, 'saved'
+                print(fn, 'saved')
             shot_idx += 1
     cv2.destroyAllWindows()

samples/python2/video_threaded.py

@@ -15,6 +15,8 @@ Keyboard shortcuts:
    space - switch between multi and single threaded processing
 '''
 
+# Python 2/3 compatibility
+from __future__ import print_function
 
 import numpy as np
 import cv2
@@ -37,7 +39,7 @@ class DummyTask:
 if __name__ == '__main__':
     import sys
 
-    print __doc__
+    print(__doc__)
 
     try:
         fn = sys.argv[1]