Hough lines

git-svn-id: https://code.ros.org/svn/opencv/trunk@2770 73c94f0f-984f-4a5f-82bc-2d8db8d8ee08

diff --git a/opencv/samples/python/houghlines.py b/opencv/samples/python/houghlines.py
new file mode 100755 (executable)
index 0000000..79e788c
--- /dev/null
+++ b/opencv/samples/python/houghlines.py
@@ -0,0 +1,57 @@
+#!/usr/bin/python
+# This is a standalone program. Pass an image name as a first parameter of the program.
+
+import sys
+from math import sin, cos, sqrt, pi
+import cv
+import urllib2
+
+# toggle between CV_HOUGH_STANDARD and CV_HOUGH_PROBILISTIC
+USE_STANDARD = True
+
+if __name__ == "__main__":
+    if len(sys.argv) > 1:
+        filename = sys.argv[1]
+        src = cv.LoadImage(filename, cv.CV_LOAD_IMAGE_GRAYSCALE)
+    else:
+        url = 'https://code.ros.org/svn/opencv/trunk/opencv/doc/pics/building.jpg'
+        filedata = urllib2.urlopen(url).read()
+        imagefiledata = cv.CreateMatHeader(1, len(filedata), cv.CV_8UC1)
+        cv.SetData(imagefiledata, filedata, len(filedata))
+        src = cv.DecodeImageM(imagefiledata, cv.CV_LOAD_IMAGE_GRAYSCALE)
+
+
+    cv.NamedWindow("Source", 1)
+    cv.NamedWindow("Hough", 1)
+
+    while True:
+        dst = cv.CreateImage(cv.GetSize(src), 8, 1)
+        color_dst = cv.CreateImage(cv.GetSize(src), 8, 3)
+        storage = cv.CreateMemStorage(0)
+        lines = 0
+        cv.Canny(src, dst, 50, 200, 3)
+        cv.CvtColor(dst, color_dst, cv.CV_GRAY2BGR)
+
+        if USE_STANDARD:
+            lines = cv.HoughLines2(dst, storage, cv.CV_HOUGH_STANDARD, 1, pi / 180, 100, 0, 0)
+            for (rho, theta) in lines[:100]:
+                a = cos(theta)
+                b = sin(theta)
+                x0 = a * rho 
+                y0 = b * rho
+                pt1 = (cv.Round(x0 + 1000*(-b)), cv.Round(y0 + 1000*(a)))
+                pt2 = (cv.Round(x0 - 1000*(-b)), cv.Round(y0 - 1000*(a)))
+                cv.Line(color_dst, pt1, pt2, cv.RGB(255, 0, 0), 3, 8)
+        else:
+            lines = cv.HoughLines2(dst, storage, cv.CV_HOUGH_PROBABILISTIC, 1, pi / 180, 50, 50, 10)
+            for line in lines:
+                cv.Line(color_dst, line[0], line[1], cv.CV_RGB(255, 0, 0), 3, 8)
+
+        cv.ShowImage("Source", src)
+        cv.ShowImage("Hough", color_dst)
+
+        k = cv.WaitKey(0)
+        if k == ord(' '):
+            USE_STANDARD = not USE_STANDARD
+        if k == 27:
+            break