From 56fe676c66a8f6c75e0b4b90f4170cf5bb6af5fa Mon Sep 17 00:00:00 2001
From: Stefan van der Walt <stefan@sun.ac.za>
Date: Sat, 16 Jul 2011 14:15:39 -0500
Subject: [PATCH] ENH: Add hough transform plot.

---
 doc/source/plots/hough_tf.py | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 doc/source/plots/hough_tf.py

diff --git a/doc/source/plots/hough_tf.py b/doc/source/plots/hough_tf.py
new file mode 100644
index 00000000..663edff1
--- /dev/null
+++ b/doc/source/plots/hough_tf.py
@@ -0,0 +1,30 @@
+import numpy as np
+import matplotlib.pyplot as plt
+
+from scikits.image.transform import hough
+
+img = np.zeros((100, 150), dtype=bool)
+img[30, :] = 1
+img[:, 65] = 1
+img[35:45, 35:50] = 1
+for i in range(90):
+    img[i, i] = 1
+img += np.random.random(img.shape) > 0.95
+
+out, angles, d = hough(img)
+
+plt.subplot(1, 2, 1)
+
+plt.imshow(img, cmap=plt.cm.gray)
+plt.title('Input image')
+
+plt.subplot(1, 2, 2)
+plt.imshow(out, cmap=plt.cm.bone,
+           extent=(d[0], d[-1],
+                   np.rad2deg(angles[0]), np.rad2deg(angles[-1])))
+plt.title('Hough transform')
+plt.xlabel('Angle (degree)')
+plt.ylabel('Distance (pixel)')
+
+plt.subplots_adjust(wspace=0.4)
+plt.show()