MLX90255-BA
Linear Optical Array
6. Cosine Correction
When using a single LED light source, which is placed above the middle of the die, the light intensity that
falls onto the outer pixels is lower than the light intensity that falls onto the middle pixels (due to the
distance die-LED, the shape of the LED light emission and the sensitivity of pixels vs. angle of incident
light). To compensate for these effects, each pixel in the array has a slightly different gain correction with
respect to the centre of the array. For a light source to photodiode array distance of 15mm the relative
pixels sensitivities are shown in the table below.
Pixel
number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
132
131
130
129
128
127
126
125
124
123
122
121
120
119
118
117
116
Relative
Pixel
Sensitivity
1.1703
1.1649
1.1596
1.1544
1.1493
1.1442
1.1393
1.1345
1.1298
1.1251
1.1206
1.1161
1.1117
1.1074
1.1032
1.0991
1.0951
Pixel
number
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
115
114
113
112
111
110
109
108
107
106
105
104
103
102
101
100
99
Relative
Pixel
Sensitivity
1.0912
1.0874
1.0836
1.0799
1.0764
1.0729
1.0695
1.0661
1.0629
1.0598
1.0567
1.0537
1.0508
1.0480
1.0453
1.0426
1.0400
Pixel
number
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
98
97
96
95
94
93
92
91
90
89
88
87
86
85
84
83
82
Relative
Pixel
Sensitivity
1.0376
1.0352
1.0328
1.0306
1.0284
1.0263
1.0243
1.0224
1.0206
1.0188
1.0171
1.0155
1.0140
1.0126
1.0112
1.0099
1.0087
Pixel
number
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
81
80
79
78
77
76
75
74
73
72
71
70
69
68
67
Relative
Pixel
Sensitivity
1.0076
1.0066
1.0056
1.0047
1.0039
1.0031
1.0025
1.0019
1.0014
1.0010
1.0006
1.0003
1.0002
1.0000
1.0000
390109025502
Rev. 008
Page 6 of 12
Nov/05
MELEXIS [ Melexis Microelectronic Systems ]
