User's Manual

The secret to a good thermal image33
Figure 33.11 Change in emissivity for a saved image. The maximum temperature is 65.0°C (149°F) for ε
= 0.95 in the left image and 77.3°C (171.1°F) for ε = 0.7 in the right image.
33.6 Taking images—practical tips
The following list includes some practical tips. However, note that this is not a compre-
hensive description of the thermal imaging procedure.
• Ensure that the camera is saving radiometric images.
• Choose an appropriate position from which to take images:
◦ Observe the radiative situation.
◦ Check that the object is clearly visible and displayed at an appropriate size and
position.
• If you change the emissivity, monitor the temperature range and make sure that it re-
mains appropriate.
• Focus.
• Use a tripod to minimize camera shake.
• Carry out thermal tuning.
• Take note of the object description, object size, actual distance, environmental condi-
tions, and operating conditions.
It is easier to edit the thermal image when it is saved or “frozen” (in “Preview”). Also,
since you don't have to do everything on site, you can leave dangerous zones immedi-
ately after taking the image. If possible, take a few more images than you need—includ-
ing from different angles. This is preferable to taking too few! You can then choose the
best image afterwards, at leisure.
33.7 Conclusion
Taking a good thermal image does not require any magic tricks—solid craft and sound
work is all that is required. Many of the points mentioned may seem trivial and “old news,”
particularly to amateur photographers. Of course, the equipment plays a role easier to
ensure sharp images. Better, i.e. high-definition, cameras allow the fast localization of
even small anomalies, and without focusing capabilities it is always difficult to capture a
sharp image. However, high-end cameras are no guarantee of good images if used in-
correctly. The basis for good, professional work is education and training in thermogra-
phy, exchange of knowledge with other thermographers, and, of course, practical
experience.
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