Basics
4
Basics
4.1
Measurement
of
Infrared
Temperature
All
surfaces
emit
infrared
radiation
The
intensity
of
this
infrared
radiation
changes
according
to
the
temperature
of
the
object.
Depending
on
the
material
and
surface
properties,
the
emitted
radiation
lies
in
a
wavelength
spectrum
of
approximately
1
to
20
μ
m.
The
intensity
of
the
infrared
radiation
(”heat
radiation”)
is
dependent
on
the
material.
For
many
substances
this
material
‐
dependent
constant
is
known.
This
constant
is
referred
to
as
the
”emissivity
value”.
Infrared
thermometers
are
optical
‐
electronic
sensors.
These
sensors
are
sensitive
to
the
emitted
radiation.
Infrared
thermometers
are
made
up
of
a
lens,
a
spectral
filter,
a
sensor,
and
an
electronic
signal
processing
unit.
The
task
of
the
spectral
filter
is
to
select
the
wavelength
spectrum
of
interest.
The
sensor
converts
the
infrared
radiation
into
an
electrical
signal.
The
signal
processing
electronics
analyze
the
electrical
signals
and
convert
it
into
a
temperature
measurement.
As
the
intensity
of
the
emitted
infrared
radiation
is
dependent
on
the
material,
the
required
emissivity
can
be
selected
on
the
sensor.
The
biggest
advantage
of
the
infrared
thermometer
is
its
ability
to
measure
temperature
without
touching
an
object.
Consequently,
surface
temperatures
of
moving
or
hard
to
reach
objects
can
easily
be
measured.
MID
11
