TABLE 9-5 Values of K(α) for Various Configurations of n1 − 1, n2, ∆1, ∆2, and α for the Pessimistic Scenario

1

n1 − 1

2

n2

Confidence Level

50%

75%

90%

99%

3

1,000

5

1,000

17

52

82

135

3

1,000

6

10,000

17

51

82

135

3

1,000

7

100,000

17

51

81

133

4

10,000

6

10,000

24

113

192

330

4

10,000

7

100,000

24

112

192

330

4

10,000

8

1,000,000

24

112

190

325

5

10,000

7

10,000

3

20

35

60

5

10,000

8

100,000

3

20

35

62

5

10,000

9

1,000,000

3

19

35

61

6

100,000

8

100,000

2

25

50

85

6

100,000

9

1,000,000

2

24

44

76

6

100,000

10

10,000,000

2

26

50

80

7

1,000,000

9

1,000,000

1

30

50

90

7

1,000,000

10

10,000,000

1

26

48

85

holds if ∆2 is 3 units bigger than ∆1 and n2 =10n1 or if ∆2 is 4 units bigger than ∆1 and n2 = 100n1. So, for instance, the ability to detect matches in a relatively small database containing equal numbers of moderately distinct images (∆1 = 4, ∆2 = 6; 10,000 each) is comparable to that when one small set of images (∆1 = 4; 10,000) is flooded with 1,000,000 images that are vastly different in mean (∆2 = 8).



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