Added character comparison script that uses histogram intersection.

src/Histogram.py

@@ -16,3 +16,15 @@ class Histogram:
     def get_bin_index(self, number):
         return (number - self.min) / ((self.max - self.min) / len(self.bins))
 
+    def intersect(self, other):
+        h1 = self.bins
+        h2 = other.bins
+
+        match = 0
+
+        # Add the minimum of each bin to the result
+        for b in xrange(len(self.bins)):
+            match += min(h1[b], h2[b])
+
+        # Normalize by dividing by the number of pixels
+        return float(match) / sum(h2)

src/test_compare.py

+#!/usr/bin/python
+from matplotlib.pyplot import imshow, subplot, show
+from LocalBinaryPatternizer import LocalBinaryPatternizer
+from GrayscaleImage import GrayscaleImage
+from cPickle import load
+from numpy import zeros, resize
+
+chars = load(file('chars', 'r'))[::2]
+left = None
+right = None
+
+for c in chars:
+    if c.value == '8':
+        if left == None:
+            left = c.image
+        elif right == None:
+            right = c.image
+        else:
+            break
+
+size = 16
+
+d = (left.size[0] * 4, left.size[1] * 4)
+#GrayscaleImage.resize(left, d)
+#GrayscaleImage.resize(right, d)
+
+p1 = LocalBinaryPatternizer(left, size)
+p1.create_features_vector()
+p1 = p1.features
+p2 = LocalBinaryPatternizer(right, size)
+p2.create_features_vector()
+p2 = p2.features
+
+s = (len(p1), len(p1[0]))
+match = zeros(left.shape)
+m = 0
+
+for y in range(s[0]):
+    for x in range(s[1]):
+        h1 = p1[y][x]
+        h2 = p2[y][x]
+        intersect = h1.intersect(h2)
+        print intersect
+
+        for i in xrange(size):
+            for j in xrange(size):
+                try:
+                    match[y*size + i, x*size + j] = 1 - intersect
+                except IndexError:
+                    pass
+
+        m += intersect
+
+print 'Match: %d%%' % int(m / (s[0] * s[1]) * 100)
+
+subplot(311)
+imshow(left.data, cmap='gray')
+subplot(312)
+imshow(match, cmap='gray')
+subplot(313)
+imshow(right.data, cmap='gray')
+
+show()