-
Notifications
You must be signed in to change notification settings - Fork 0
/
distance_metrics.py
94 lines (68 loc) · 2.93 KB
/
distance_metrics.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
# python -m unittest harris_corner_detector
import numpy as np
import unittest
def sum_of_absolute_differences(a, b):
return np.sum(np.abs(a - b))
def sum_of_squared_differences(a, b):
return np.sum(np.square(a - b))
def cross_correlation(a, b):
return np.sum(a * b)
def normalised_cross_correlation(a, b):
numerator = cross_correlation(a, b)
denominator = np.sqrt(np.sum(a * a)) * np.sqrt(np.sum(b * b))
return numerator / denominator
def cosine(a, b):
return normalised_cross_correlation(a, b)
def correlation_coefficient(a, b):
normalised_a = a - np.mean(a)
normalised_b = b - np.mean(b)
numerator = cross_correlation(normalised_a, normalised_b)
denominator = np.sqrt(np.sum(np.square(normalised_a))) * np.sqrt(np.sum(np.square(normalised_b)))
return numerator / denominator
def euclidean_distance(a, b):
return np.sqrt(np.sum(np.square(a - b)))
class TestDistanceMetrics(unittest.TestCase):
T1 = np.array([
[1, 1, 1],
[1, 0, 0],
[1, 1, 1],
])
T2 = np.array([
[1, 0, 0],
[1, 0, 0],
[1, 1, 1],
])
T3 = np.array([
[1, 1, 1],
[1, 0, 1],
[1, 1, 1],
])
I = np.array([
[1, 1, 1],
[1, 0, 0],
[1, 1, 1],
])
def test_cross_correlation(self):
self.assertEqual(cross_correlation(self.T1, self.I), 7)
self.assertEqual(cross_correlation(self.T2, self.I), 5)
self.assertEqual(cross_correlation(self.T3, self.I), 7)
def test_normalised_cross_correlation(self):
self.assertEqual(round(normalised_cross_correlation(self.T1, self.I), 2), 1)
self.assertEqual(round(normalised_cross_correlation(self.T2, self.I), 2), 0.85)
self.assertEqual(round(normalised_cross_correlation(self.T3, self.I), 2), 0.94)
def test_correlation_coefficient(self):
self.assertEqual(round(correlation_coefficient(self.T1, self.I), 2), 1)
self.assertEqual(round(correlation_coefficient(self.T2, self.I), 2), 0.60)
self.assertEqual(round(correlation_coefficient(self.T3, self.I), 2), 0.66)
def test_sum_of_absolute_differences(self):
self.assertEqual(round(sum_of_absolute_differences(self.T1, self.I), 2), 0)
self.assertEqual(round(sum_of_absolute_differences(self.T2, self.I), 2), 2)
self.assertEqual(round(sum_of_absolute_differences(self.T3, self.I), 2), 1)
def test_sum_of_squared_differences(self):
self.assertEqual(round(sum_of_squared_differences(self.T1, self.I), 2), 0)
self.assertEqual(round(sum_of_squared_differences(self.T2, self.I), 2), 2)
self.assertEqual(round(sum_of_squared_differences(self.T3, self.I), 2), 1)
def test_euclidean_distance(self):
self.assertEqual(round(euclidean_distance(self.T1, self.I), 2), 0)
self.assertEqual(round(euclidean_distance(self.T2, self.I), 2), 1.41)
self.assertEqual(round(euclidean_distance(self.T3, self.I), 2), 1)