MikroScan 7600PRO, Руководство оператора

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Section 8
282
MikroScan 7600PRO
Operator’s Manual
Catalog 11180-94
V15.4F 050406
Principle of Thermal Imaging
8.7 Practical Measurement
There are a number of methods for correctng emssvty n order to obtan the true tem-
perature. The correcton procedure wth each method wll be explaned next.
(1) Method of comparison or direct measurement with emissivity equal
to approximately 1.0
a) Stablze the temperature of the measured object or smlar
materal.
b) Open a very small hole (hereafter called blackbody part) n the
object whch the thermal mager must measure as to satsfy
blackbody condtons.
c) Then set the emssvty correctng functon of thermal mager
so that the temperature of the blackbody part and the measured
surface wll be the same. The obtaned emssvty wll be the
emssvty of the measured surface.
d) Thereafter when measuring the same type object, it is unnecessary
to change the emssvty settng.
(2) Method of direct measurement of emissivity
If a hole cannot be made as in method 1, then apply black high
emssvty pant and carry out the same procedures to obtan the
emissivity. Since the black paint will not provide a perfect blackbody,
first set the emissivity of the black paint and then measure the
temperature.
(3) Indirect measurement
Measure a sample similar to the measured object, and place it in a con -
dition able to be heated by a heater, etc. Then measure the object and the
sample alternately wth the camera and when the ndcated values are
identical, measure the sample with a contact-type thermometer. Adjust
the emssvty of the thermal mager to cause the temperature readout to
match that of the contact measurement. The resultng emssvty s that
of the sample.
(4) Measuring by Wedge effect
With this method, the emissivity of the measured surface itself is
enhanced through use of the wedge or sem-wedge effect. But one must
be careful about the number of reflections and/or the measuring angle.
A small change n angle wll reduce the emssvty enhancement.
Note:
If you already know the
emissivity, you can make
thermal imaging measure-
ments immediately.
Measuring by wedge effect