Chauvin Arnoux C.A 1875, Руководство пользователя

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65
The principle of the conservation of energy yields the following equation:
α . I(T) + ρ . I(T) + τ . I(T) = I(T) ,
or α + ρ + τ = 1
At equilibrium, the object emits
ε (T) the same quantity of energy as it absorbs α (T).
This gives the following equation:
α . I(T) = ε . I(T)
or
α
=
ε
Whence:
ε + ρ + τ = 1
In thermography, it is possible to make measurements only on opaque bodies. The
transmission of the materials is therefore zero.
This gives the equation:
ε + ρ = 1
and ρ = 1 - ε
Thus, when making a measurement by thermography, it is necessary to make
allowance for reflected "ambient" radiation. A real measurement situation is
therefore:
And the total radiation received by the camera is therefore:
R
measured
= R
object
+ R
reflected
ε . σ . (T
object
)
4
ρ . σ . (T
reflected
)
4
Reflected radiation of the
environment on the object
Radiation of the object
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