Page 77 - Sensors and Control Systems in Manufacturing

The Role of Sensors in the 21st Century
1.15.12 Calculating Four Calculation Points: 39

2
.
.
.
.
(
E
P = 0 93 R E +1 5 E + 0 75 E + 0 125 )
3 2 1 0
1.15.13 Calculating Five Calculation Points:
2
.
E
(
.
.
.
.
0
P = 072 R E +164 E +109 E + 055 E + 009 )
3
2
4
1
1.15.14 Calculating Eight Points:
+
2
.
.
.
.
.
E
(
.
.
.
0
P = 043 R E +18 E +15 E +12 E + 09 E + 06 E + 03 E + 005 )
2
4
3
1
5
6
7
where P = total lumens
R = beam radius
E = illumination
In the case of a “soft edge” fixture, where the image size is taken
at 10 percent of the center illumination (field angle), the formula
becomes:
2
P = 126 R E
.
center
1.16 LED and Spectralon
1.16.1 Spectralon® Material—Light Reflectance Calibration
Spectralon reflectance standards (Fig. 1.24) are available individually
and in sets consisting of a diffuse white standard and a selection of
diffuse gray standards. Each is supplied with reflectance data from
250 nm to 2500 nm, in 50-nm increments. These durable, chemically
FIGURE 1.24 Spectralon ® diffuse white standards provide the highest diffuse
refl ectance values of any known substance.