FLIR Ranger HRC MS, Руководство оператора

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Ranger HRC™ operator´s manual – Theory of thermal imaging
Publ. No. TM G007971 Rev. A1 – ENGLISH (EN) – Sept 09. 2008
1
2
10
-1
10
1
0 5 10 15 20 25 30
10
-2
1
10
-3
10
-4
10
-5
1000 K
800
700
600
500
900
400
300
200
100
Figure 17.6 Planckian curves plotted on semi-log scales from 100 K to 1.000 K. The dotted
line represents the locus of maximum radiant exitance at each temperature as described by
Wien’s displacement law. 1: Spectral radiant exitance (W/cm2 (μm)); 2: Wavelength (μm).
17.3.3 Stefan­Boltzmann’s law
By integrating Planck’s formula from
l
= 0 to
l
= ∞, we obtain the total
radiant exitance (­M
e
) of a blackbody:
[ ]
2 4
/ m W T M
e
σ =
[ ]
4 2 8
/ 10 67 . 5 K m W
−
⋅ = σ
where
This is the Stefan-Boltzmann formula (­after
Josef Stefan
, 1835–1893,
and
Ludwig Boltzmann
, 1844–1906), which states that the total emissive
power of a blackbody is proportional to the fourth power of its absolute
temperature. Graphically, M
e
represents the area below the Planck curve
for a particular temperature. It can be shown that the radiant exitance in
the interval
l
= 0 to
l
max
is only 25 % of the total, which represents about
the amount of the sun’s radiation which lies inside the visible light spec-
trum.