samples/python/distrans.py

   1 #!/usr/bin/python
   2 import sys
   3 import cv2.cv as cv
   4 import urllib2
   5
   6 wndname = "Distance transform"
   7 tbarname = "Threshold"
   8
   9 # The output images
  10 dist = 0
  11 dist8u1 = 0
  12 dist8u2 = 0
  13 dist8u = 0
  14 dist32s = 0
  15
  16 gray = 0
  17 edge = 0
  18
  19 # define a trackbar callback
  20 def on_trackbar(edge_thresh):
  21
  22     cv.Threshold(gray, edge, float(edge_thresh), float(edge_thresh), cv.CV_THRESH_BINARY)
  23     #Distance transform
  24     cv.DistTransform(edge, dist, cv.CV_DIST_L2, cv.CV_DIST_MASK_5)
  25
  26     cv.ConvertScale(dist, dist, 5000.0, 0)
  27     cv.Pow(dist, dist, 0.5)
  28
  29     cv.ConvertScale(dist, dist32s, 1.0, 0.5)
  30     cv.AndS(dist32s, cv.ScalarAll(255), dist32s, None)
  31     cv.ConvertScale(dist32s, dist8u1, 1, 0)
  32     cv.ConvertScale(dist32s, dist32s, -1, 0)
  33     cv.AddS(dist32s, cv.ScalarAll(255), dist32s, None)
  34     cv.ConvertScale(dist32s, dist8u2, 1, 0)
  35     cv.Merge(dist8u1, dist8u2, dist8u2, None, dist8u)
  36     cv.ShowImage(wndname, dist8u)
  37
  38
  39 if __name__ == "__main__":
  40     edge_thresh = 100
  41
  42     if len(sys.argv) > 1:
  43         gray = cv.LoadImage(sys.argv[1], cv.CV_LOAD_IMAGE_GRAYSCALE)
  44     else:
  45         url = 'http://code.opencv.org/svn/opencv/trunk/opencv/samples/c/stuff.jpg'
  46         filedata = urllib2.urlopen(url).read()
  47         imagefiledata = cv.CreateMatHeader(1, len(filedata), cv.CV_8UC1)
  48         cv.SetData(imagefiledata, filedata, len(filedata))
  49         gray = cv.DecodeImage(imagefiledata, cv.CV_LOAD_IMAGE_GRAYSCALE)
  50
  51     # Create the output image
  52     dist = cv.CreateImage((gray.width, gray.height), cv.IPL_DEPTH_32F, 1)
  53     dist8u1 = cv.CloneImage(gray)
  54     dist8u2 = cv.CloneImage(gray)
  55     dist8u = cv.CreateImage((gray.width, gray.height), cv.IPL_DEPTH_8U, 3)
  56     dist32s = cv.CreateImage((gray.width, gray.height), cv.IPL_DEPTH_32S, 1)
  57
  58     # Convert to grayscale
  59     edge = cv.CloneImage(gray)
  60
  61     # Create a window
  62     cv.NamedWindow(wndname, 1)
  63
  64     # create a toolbar
  65     cv.CreateTrackbar(tbarname, wndname, edge_thresh, 255, on_trackbar)
  66
  67     # Show the image
  68     on_trackbar(edge_thresh)
  69
  70     # Wait for a key stroke; the same function arranges events processing
  71     cv.WaitKey(0)
  72     cv.DestroyAllWindows()